US LAWS, STATUTES & CODES ON-LINE

(b) In rounding the nominal power in accordance with paragraph (a) of this section the RMS shall be adjusted accordingly. If rounding upward to the nearest figure would result in objectionable interference, the nominal power specified on the application is to be rounded downward to the next nearest figure and the RMS adjusted accordingly.

[50 FR 18821, May 2, 1985, as amended at 53 FR 1031, Jan. 15, 1988]

(a) An application for authority to install a broadcast antenna shall specify a definite site and include full details of the antenna design and expected performance.

(b) All data necessary to show compliance with the terms and conditions of the construction permit must be filed with the license application. If the station is using a directional antenna, a proof of performance must also be filed.

[28 FR 13574, Dec. 14, 1963, as amended at 37 FR 25840, Dec. 5, 1972]

A petition for an allotment (See §73.30) in the 1605–1705 kHz band filed by an existing fulltime AM station licensed in the 535–1605 kHz band will be ranked according to the station's calculated improvement factor. (See §73.30). Improvement factors relate to both nighttime and daytime interference conditions and are based on two distinct considerations: (a) Service area lost by other stations due to interference caused by the subject station, and (b) service area of the subject station. These considerations are represented by a ratio. The ratio consists, where applicable, of two separate additive components, one for nighttime and one for daytime. For the nighttime component, to determine the numerator of the ratio (first consideration), calculate the RSS and associated service area of the stations (co- and adjacent channel) to which the subject station causes nighttime interference. Next, repeat the RSS and service area calculations excluding the subject station. The cumulative gain in the above service area is the numerator of the ratio. The denominator (second consideration) is the subject station's interference-free service area. For the daytime component, the composite amount of service lost by co-channel and adjacent channel stations, each taken individually, that are affected by the subject station, excluding the effects of other assignments during each study, will be used as the numerator of the daytime improvement factor. The denominator will consist of the actual daytime service area (0.5 mV/m contour) less any area lost to interference from other assignments. The value of this combined ratio will constitute the petitioner's improvement factor. Notwithstanding the requirements of §73.153, for uniform comparisons and simplicity, measurement data will not be used for determining improvement factors and FCC figure M-3 ground conductivity values are to be used exclusively in accordance with the pertinent provisions of §73.183(c)(1).

[56 FR 64858, Dec. 12, 1991]

(a) No application will be accepted for a new station if the proposed operation would involve overlap of signal strength contours with any other station as set forth below in this paragraph; and no application will be accepted for a change of the facilities of an existing station if the proposed change would involve such overlap where there is not already such overlap between the stations involved:

(b) In determining overlap received, an application for a new Class C station with daytime power of 250 watts, or greater, shall be considered on the assumption that both the proposed operation and all existing Class C stations operate with 250 watts and utilize non-directional antennas.

(c) If otherwise consistent with the public interest, an application requesting an increase in the daytime power of an existing Class C station on a local channel from 250 watts to a maximum of 1kW, or from 100 watts to a maximum of 500 watts, may be granted notwithstanding overlap prohibited by paragraph (a) of this section. In the case of a 100 watt Class C station increasing daytime power, the provisions of this paragraph shall not be construed to permit an increase in power to more than 500 watts, if prohibited overlap would be involved, even if successive applications should be tendered.

(d) In addition to demonstrating compliance with paragraphs (a), and, as appropriate, (b), and (c) of this section, an application for a new AM broadcast station, or for a major change (see §73.3571(a)(1)) in an authorized AM broadcast station, as a condition for its acceptance, shall make a satisfactory showing, if new or modified nighttime operation by a Class B station is proposed, that objectionable interference will not result to an authorized station, as determined pursuant to §73.182(1).

(e) An application for an authorization in the 1605–1705 kHz band which has been selected through the petition process (See §73.30) is not required to demonstrate compliance with paragraph (a), (b), (c), or (d) of this section. Instead, the applicant need only comply with the terms of the allotment authorization issued by the Commission in response to the earlier petition for establishment of a station in the 1605–1705 kHz band. Within the allotment authorization, the Commission will specify the assigned frequency and the applicable technical requirements.

(f) Stations on 1580, 1590 and 1600 kHz. In addition to the rules governing the authorization of facilities in the 535–1605 kHz band, stations on these frequencies seeking facilities modifications must protect assignments in the 1610–1700 kHz band. Such protection shall be afforded in a manner which considers the spacings that occur or exist between the subject station and a station within the range 1605–1700 kHz. The spacings are the same as those specified for stations in the frequency band 1610–1700 kHz or the current separation distance, whichever is greater. Modifications that would result in a spacing or spacings that fails to meet any of the separations must include a showing that appropriate adjustment has been made to the radiated signal which effectively results in a site-to-site radiation that is equivalent to the radiation of a station with standard Model I facilities (10 kW-D, 1 kW-N, non-DA, 90 degree antenna ht. & ground system) operating in compliance with all of the above separation distances. In those cases where that radiation equivalence value is already exceeded, a station may continue to maintain, but not increase beyond that level.

Note 1: In the case of applications for changes in the facilities of AM broadcast stations covered by this section, an application will be accepted even though overlap of field strength contours as mentioned in this section would occur with another station in an area where such overlap does not already exist, if:

Note 2: The provisions of this section concerning prohibited overlap of field strength contours will not apply where:

Note 3: In determining the number of “authorized” aural transmission facilities in a given community, applications for that community in hearing or otherwise having protected status under specified “cut-off” procedures shall be considered as existing stations. In the event that there are two or more mutually exclusive protected applications seeking authorization for the proposed community it will be assumed that only one is “authorized.”

Note 4: A “transmission facility” for a community is a station licensed to the community. Such a station provides a “transmission service” for that community.

[56 FR 64858, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

(a) The emissions of stations in the AM service shall be attenuated in accordance with the requirements specified in paragraph (b) of this section. Emissions shall be measured using a properly operated and suitable swept-frequency RF spectrum analyzer using a peak hold duration of 10 minutes, no video filtering, and a 300 Hz resolution bandwidth, except that a wider resolution bandwidth may be employed above 11.5 kHz to detect transient emissions. Alternatively, other specialized receivers or monitors with appropriate characteristics may be used to determine compliance with the provisions of this section, provided that any disputes over measurement accuracy are resolved in favor of measurements obtained by using a calibrated spectrum analyzer adjusted as set forth above.

(b) Emissions 10.2 kHz to 20 kHz removed from the carrier must be attenuated at least 25 dB below the unmodulated carrier level, emissions 20 kHz to 30 kHz removed from the carrier must be attenuated at least 35 dB below the unmodulated carrier level, emissions 30 kHz to 60 kHz removed from the carrier must be attenuated at least [5 + 1 dB/kHz] below the unmodulated carrier level, and emissions between 60 kHz and 75 kHz of the carrier frequency must be attenuated at least 65 dB below the unmodulated carrier level. Emissions removed by more than 75 kHz must be attenuated at least 43 + 10 Log (Power in watts) or 80 dB below the unmodulated carrier level, whichever is the lesser attenuation, except for transmitters having power less than 158 watts, where the attenuation must be at least 65 dB below carrier level.

(c) Should harmful interference be caused to the reception of other broadcast or non-broadcast stations by out of band emissions, the licensee may be directed to achieve a greater degree of attentuation than specified in paragraphs (a) and (b) of this section.

(d) Measurements to determine compliance with this section for transmitter type acceptance are to be made using signals sampled at the output terminals of the transmitter when operating into an artificial antenna of substantially zero reactance. Measurements made of the emissions of an operating station are to be made at ground level approximately 1 kilometer from the center of the antenna system. When a directional antenna is used, the carrier frequency reference field strength to be used in order of preference shall be:

(1) The measure non-directional field strength.

(2) The RMS field strength determined from the measured directional radiation pattern.

(3) The calculated expected field strength that would be radiated by a non-directional antenna at the station authorized power.

(e) Licensees of stations complying with the ANSI/EIA–549–1988, NRSC–1 AM Preemphasis/Deemphasis and Broadcast Transmission Bandwidth Specifications (NRSC–1), prior to June 30, 1990 or from the original commencement of operation will, until June 30, 1994, be considered to comply with paragraphs (a) and (b) of this section, absent any reason for the Commission to believe otherwise. Such stations are waived from having to make the periodic measurements required in §73.1590(a)(6) until June 30, 1994. However, licensees must make measurements to determine compliance with paragraphs (a) and (b) of this section upon receipt of an Official Notice of Violation or a Notice of Apparent Liability alleging noncompliance with those provisions, or upon specific request by the Commission.

[47 FR 8588, Mar. 1, 1982, as amended at 49 FR 3999, Feb. 1, 1984]

(a) All applicants for new, additional, or different AM station facilities and all licensees requesting authority to change the transmitting system site of an existing station must specify an antenna system, the efficiency of which complies with the requirements for the class and power of station. (See §§73.186 and 73.189.)

(1) An application for authority to install an AM broadcast antenna must specify a definite site and include full details of the antenna system design and expected performance.

(2) All data necessary to show compliance with the terms and conditions of the construction permit must be filed with the application for the station license to cover the construction. If the station has constructed a directional antenna, a directional proof of performance must be filed. See §§73.150 through 73.157.

(b) The simultaneous use of a common antenna or antenna structure by more than one AM station or by a station of any other type or service may be authorized provided:

(1) Engineering data are submitted showing that satisfactory operation of each station will be obtained without adversely affecting the operation of the other station(s).

(2) The minimum field strength for each AM station complies with §73.189(b).

(c) Should any changes be made or otherwise occur which would possibly alter the resistance of the antenna system, the licensee must commence the determination of the operating power by a method described in §73.51(a)(1) or (d). (If the changes are due to the construction of FM or TV transmitting facilities, see §§73.316, 73.685, and 73.1692.) Upon completion of any necessary repairs or adjustments, or upon completion of authorized construction or modifications, the licensee must make a new determination of the antenna resistance using the procedures described in §73.54. Operating power should then be determined by a direct method as described in §73.51. Notification of the value of resistance of the antenna system must be filed with the FCC in Washington, DC as follows:

(1) Whenever the measurements show that the antenna or common point resistance differs from that shown on the station authorization by more than 2%, FCC Form 302 must be filed with the information and measurement data specified in §73.54(d).

(2) Whenever AM stations use direct reading power meters pursuant to §73.51, a letter notification to the FCC in Washington, DC, Attention: Audio Division, Media Bureau, must be filed in accordance with §73.54(e).

[43 FR 53735, Nov. 17, 1978, as amended at 45 FR 28141, Apr. 28, 1980; 47 FR 8589, Mar. 1, 1982; 50 FR 32416, Aug. 12, 1985; 51 FR 2707; Jan. 21, 1986; 51 FR 26250, July 22, 1986; 63 FR 33875, June 22, 1998; 67 FR 13231, Mar. 21, 2002]

Antenna towers having radio frequency potential at the base (series fed, folded unipole, and insulated base antennas) must be enclosed within effective locked fences or other enclosures. Ready access must be provided to each antenna tower base for meter reading and maintenance purposes at all times. However, individual tower fences need not be installed if the towers are contained within a protective property fence.

[51 FR 2707, Jan. 21, 1986]

(a) Except in those circumstances described in paragraph (d) of this section, the operating power shall be determined by the direct method. The direct method consists of either:

(1) using a suitable instrument for determining the antenna's input power directly from the RF voltage, RF current, and phase angle; or

(2) calculating the product of the licensed antenna or common point resistance at the operating frequency (see §73.54), and the square of the indicated unmodulated antenna current at that frequency, measured at the point where the resistance has been determined.

(b) The authorized antenna input power for each station shall be equal to the nominal power for such station, with the following exceptions:

(1) For stations with nominal powers of 5 kW, or less, the authorized antenna input power to directional antennas shall exceed the nominal power by 8 percent.

(2) For stations with nominal powers in excess of 5 kW, the authorized antenna input power to directional antennas shall exceed the nominal power by 5.3 percent.

(3) In specific cases, it may be necessary to limit the radiated field to a level below that which would result if normal power were delivered to the antenna. In such cases, excess power may be dissipated in the antenna feed circuit, the transmitter may be operated with power output at a level which is less than the rated carrier power, or a combination of the two methods may be used, subject to the conditions given in paragraph (c) of this section.

(i) Where a dissipative network is employed, the authorized antenna current and resistance, and the authorized antenna input power shall be determined at the input terminals of the dissipative network.

(ii) Where the authorized antenna input power is less than the nominal power, subject to the conditions set forth in paragraph (c) of this section, the transmitter may be operated at the reduced power level necessary to supply the authorized antenna input power.

(c) Applications for authority to operate with antenna input power which is less than nominal power and/or to employ a dissipative network in the antenna system shall be made on FCC Form 302. The technical information supplied on section II-A of this form shall be that applying to the proposed conditions of operation. In addition, the following information shall be furnished, as pertinent:

(1) Full details of any network employed for the purpose of dissipating radio frequency energy otherwise delivered to the antenna (see §73.54).

(2) A showing that the transmitter has been type accepted or notified for operation at the proposed power output level, or, in lieu thereof:

(i) A full description of the means by which transmitter output power will be reduced.

(ii) Where the proposed transmitter power output level(s) is less than 90% of the rated power of the transmitter, equipment performance measurements must be made to confirm that the station transmissions conform to the emission limitation specified in §73.44, under all conditions of program operation.

(iii) A showing that, at the proposed power output level, means are provided for varying the transmitter output within a tolerance of ±10 percent, to compensate for variations in line voltage or other factors which may affect the power output level.

(d) When it is not possible or appropriate to use the direct method of power determination due to technical reasons, the indirect method of determining operating power (see paragraphs (e) and (f) of this section) may be used on a temporary basis. A notation must be made in the station log indicating the dates of commencement and termination of measurement using the indirect method of power determination.

(e) The antenna input power is determined indirectly by applying an appropriate factor to the input power to the last radio-frequency power amplifier stage of the transmitter, using the following formula:

Where:

Antenna input power = Ep × Ip × F

Ep=DC input voltage of final radio stage.

(1) If the above formula is not appropriate for the design of the transmitter final amplifier, use a formula specified by the transmitter manufacturer with other appropriate operating parameters.

(2) The value of F applicable to each mode of operation must be determined and a record kept thereof with a notation as to its derivation. This factor is to be established by one of the methods described in paragraph (f) of this section and retained in the station records.

(f) The value of F is to be determined by one of the following procedures listed in order of preference:

(1) If the station had previously been authorized and operating by determining the antenna input power by the direct method, the factor F is the ratio of the antenna input power (determined by the direct method) to the corresponding final radio frequency power amplifier input power.

(2) If a station has not been previously in regular operation with the power authorized for the period of indirect power determination, if a new transmitter has been installed, or if, for any other reason, the determination of the factor F by the method described in paragraph (f)(1) of this section is impracticable:

(i) The factor F as shown in the transmitter manufacturer's test report, if such a test report specifies a unique value of F for the power level and frequently used; or

(ii) The value determined by reference to the following table:

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, as amended, 1068, 1082, as amended; 47 U.S.C. 154, 155, 303. Interpret or apply secs. 301, 303, 307, 48 Stat. 1081, 1082, as amended, 47 U.S.C. 301, 303, 307)

[37 FR 7516, Apr. 15, 1972, as amended at 42 FR 36827, July 18, 1977; 42 FR 61863, Dec. 7, 1977; 44 FR 36036, June 20, 1979; 47 FR 28387, June 30, 1982; 48 FR 38477, Aug. 24, 1983; 48 FR 44805, Sept. 30, 1983; 49 FR 3999, Feb. 1, 1984; 49 FR 4210, Feb. 3, 1984; 49 FR 49850, Dec. 24, 1984; 50 FR 24521, June 11, 1985; 52 FR 10570, Apr. 2, 1987]

(a) Antenna monitors shall be verified for compliance with the technical requirements in this section. The procedure for verification is specified in subpart J of part 2 of the FCC's rules.

(b) An antenna monitor shall meet the following specifications:

(1) The monitor shall be designed to operate in the 535–1705 kHz band.

(2) The monitor shall be capable of indicating any phase difference between two RF voltages of the same frequency over a range of from 0 to 360°.

(3) The monitor shall be capable of indicating the relative amplitude of two RF voltages.

(4) The device used to indicate phase differences shall indicate in degrees, and shall be graduated in increments of 2°, or less. If a digital indicator is provided, the smallest increment shall be 0.5°, or less.

(5) The device used to indicate relative amplitudes shall be graduated in increments which are 1 percent, or less, of the full scale value. If a digital indicator is provided, the smallest increment shall be 0.1 percent, or less, of the full scale value.

(6) The monitor shall be equipped with means, if necessary, to resolve ambiguities in indication.

(7) If the monitor is provided with more than one RF input terminal in addition to a reference input terminal, appropriate switching shall be provided in the monitor so that the signal at each of these RF inputs may be selected separately for comparison with the reference input signal.

(8) Each RF input of the monitor shall provide a termination of such characteristics that, when connected to a sampling line of an impedance specified by the manufacturer the voltage reflection coefficient shall be 3 percent or less.

(9) The monitor, if intended for use by stations operating directional antenna systems by remote control, shall be designed so that the switching functions required by paragraph (b)(7) of this section may be performed from a point external to the monitor, and phase and amplitude indications be provided by external meters. The indications of external meters furnished by the manufacturer shall meet the specifications for accuracy and repeatability of the monitor itself, and the connection of these meters to the monitor, or of other indicating instruments with electrical characteristics meeting the specifications of the monitor manufacturer shall not affect adversely the performance of the monitor in any respect.

(10) Complete and correct schematic diagrams and operating instructions shall be retained by the party responsible for verification of the equipment and submitted to the FCC upon request. For the purpose of equipment authorization, these diagrams and instructions shall be considered as part of the monitor.

(11) When an RF signal of an amplitude within a range specified by the manufacturer is applied to the reference RF input terminal of the monitor, and another RF signal of the same frequency and of equal or lower amplitude is applied to any other selected RF input terminal, indications shall be provided meeting the following specifications.

(i) The accuracy with which any difference in the phases of the applied signals is indicated shall be ±1°, or better, for signal amplitude ratios of from 2:1 to 1:1, and ±2°, or better, for signal amplitude ratios in excess of 2:1 and up to 5:1.

(ii) The repeatability of indication of any difference in the phases of the applied signals shall be ±1°, or better.

(iii) The accuracy with which the relative amplitudes of the applied signals is indicated, over a range in which the ratio of these amplitudes is between 2:1 and 1:1, shall be ±2 percent of the amplitude ratio, or better, and for amplitude ratios in excess of 2:1 and up to 5:1, ±5 percent of the ratio, or better.

(iv) The repeatability of indication of the relative amplitudes of the applied signals, over a range where the ratio of these amplitudes is between 5:1 and 1:1, shall be ±2 percent of the amplitude ratio, or better.

(v) The modulation of the RF signals by a sinusoidal wave of any frequency between 100 and 10,000 Hz, at any amplitude up to 90 percent shall cause no deviation in an indicated phase difference from its value, as determined without modulation, greater than ±0.5°.

(12) The performance specifications set forth in paragraph (b)(11) of this section, shall be met when the monitor is operated and tested under the following conditions.

(i) After continuous operation for 1 hour, the monitor shall be calibrated and adjusted in accordance with the manufacturer's instructions.

(ii) The monitor shall be subjected to variations in ambient temperature between the limits of 10 and 40 °C; external meters furnished by the manufacturer will be subjected to variations between 15 and 30 °C.

(iii) Powerline supply voltage shall be varied over a range of from 10 percent below to 10 percent above the rated supply voltage.

(iv) The amplitude of the reference signal shall be varied over the operating range specified by the manufacturer, and in any case over a range of maximum to minimum values of 3 to 1.

(v) The amplitude of the comparison signal shall be varied from a value which is 0.2 of the amplitude of the reference signal to a value which is equal in amplitude to the reference signal.

(vi) Accuracy shall be determined for the most adverse combination of conditions set forth above.

(vii) Repeatability shall be determined as that which may be achieved under the specified test conditions over a period of 7 days, during which no calibration or adjustment of the instrument, subsequent to the initial calibration, shall be made.

(viii) The effects of modulation of the RF signal shall be separately determined, and shall not be included in establishing values for accuracy and repeatability.

Note: In paragraph (b)(1) of this section, the requirement that monitors be capable of operation in the 535–1705 kHz band shall apply only to equipment manufactured after July 1, 1992. Use of a monitor in the 1605–1705 kHz band which is not approved for such operation will be permitted pending the general availability of 535–1705 kHz band monitors if a manufacturer can demonstrate, in the interim, that its monitor performs in accordance with the standards in this section on these 10 channels.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[38 FR 1917, Jan. 19, 1973, as amended at 49 FR 3999, Feb. 1, 1984; 49 FR 29069, July 18, 1984; 50 FR 32416, Aug. 12, 1985; 50 FR 47054, Nov. 14, 1985; 51 FR 2707, Jan. 21, 1986; 56 FR 64859, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992; 60 FR 55480, Nov. 1, 1995; 63 FR 36604, July 7, 1998; 66 FR 20755, Apr. 25, 2001]

(a) The resistance of an omnidirectional series fed antenna is measured at either the base of the antenna without intervening coupling or tuning networks, or at the point the transmission line connects to the output terminals of the transmitter. The resistance of a shunt excited antenna may be measured at the point the radio frequency energy is transferred to the feed wire circuit or at the output terminals of the transmitter.

(b) The resistance and reactance of a directional antenna shall be measured at the point of common radiofrequency input to the directional antenna system after the antenna has been finally adjusted for the required radiation pattern.

(c) A letter of notification must be filed with the FCC in Washington, DC, Attention: Audio Division, Media Bureau, when determining power by the direct method pursuant to §73.51. The letter must specify the antenna or common point resistance at the operating frequency. The following information must also be kept on file at the station:

(1) A full description of the method used to make measurements.

(2) A schematic diagram showing clearly all components of coupling circuits, the point of resistance measurement, the location of the antenna ammeter, connections to and characteristics of all tower lighting isolation circuits, static drains, and any other fixtures connected to and supported by the antenna, including other antennas and associated networks. Any network or circuit component used to dissipate radio frequency power shall be specifically identified, and the impedances of all components which control the level of power dissipation, and the effective input resistance of the network must be indicated.

(d) AM stations using direct reading power meters in accordance with §73.51, can either submit the information required by paragraph (c) of this section or submit a statement indicating that such a meter is being used. Subsequent station licenses will indicate the use of a direct reading power meter in lieu of the antenna resistance value in such a situation.

[66 FR 20755, Apr. 25, 2001,as amended at 67 FR 13231, Mar. 21, 2002]

Remote reading antenna and common point ammeters may be used without further authority according to the following conditions:

(a) Remote reading antenna or common point ammeters may be provided by:

(1) Inserting second radio frequency current sensing device directly in the antenna circuit with remote leads to the indicating instruments.

(2) Inductive coupling to radio frequency current sensing device for providing direct current to indicating instrument.

(3) Capacity coupling to radio frequency current sensing device for providing direct current to indicating instrument.

(4) Current transformer connected to radio frequency current sensing device for providing direct current to indicating instrument.

(5) Using transmission line current meter at transmitter as remote reading ammeter. See paragraph (c) of this section.

(6) Using the indications of the antenna (phase) monitor, provided that when the monitor is used to obtain remote reading indication of non-directional antenna base current, the monitor calibration can be independently made and maintained for each mode of operation.

(b) Devices used for obtaining remote reading antenna or common point current indications, except antenna monitor coupling elements, shall be located at the same point as, but below (transmitter side) the associated main ammeter.

(c) In the case of shunt-excited antennas, the transmission line current meter at the transmitter may be considered as the remote antenna ammeter provided the transmission line is terminated directly into the excitation circuit feed line, which shall employ series tuning only (no shunt circuits of any type shall be employed) and insofar as practicable, the type and scale of the transmission line meter should be the same as those of the excitation circuit feed line meter (meter in slant wire feed line or equivalent).

(d) Each remote reading ammeter shall be accurate to within 2 percent of the value read on its corresponding regular ammeter.

(e) All remote reading ammeters shall conform with the specifications for regular antenna ammeters.

(f) Meters with arbitrary scale divisions may be used provided that calibration charts or curves are provided at the transmitter control point showing the relationship between the arbitrary scales and the reading of the main meters.

(g) If a malfunction affects the remote reading indicators of the antenna or common point ammeter, the operating power may be determined by a method using alternative procedures as described in §73.51.

[41 FR 36817, Sept. 1, 1976, as amended at 48 FR 38477, Aug. 24, 1983; 49 FR 49850, Dec. 24, 1984; 50 FR 32416, Aug. 12, 1985; 60 FR 55480, Nov. 1, 1995]

(a) Each AM broadcast station must be equipped with indicating instruments which conform with the specifications described in §73.1215 for determining power by the direct and indirect methods, and with such other instruments as are necessary for the proper adjustment, operation, and maintenance of the transmitting system. However, auxiliary transmitters with a nominal power rating of 100 watts or less are not required to be equipped with instruments to determine power by the indirect method provided that the licensee can determine the antenna input power at all times.

(b) Since it is usually impractical to measure the actual antenna current of a shunt excited antenna system, the current measured at the input of the excitation circuit feed line is accepted as the antenna current.

(c) The function of each instrument shall be clearly and permanently shown on the instrument itself or on the panel immediately adjacent thereto.

(d) In the event that any one of these indicating instruments becomes defective when no substitute which conforms with the required specifications is available, the station may be operated without the defective instrument pending its repair or replacement for a period not in excess of 60 days without further authority of the Commission. If the defective instrument is the antenna current meter of a nondirectional station which does not employ a remote antenna ammeter, or if the defective instrument is the common point meter of a station which employs a directional antenna and does not employ a remote common point meter, the operating power shall be determined by a method described in §73.51(a)(1) or §73.51(d) during the entire time the station is operated without the antenna current meter or common point meter. However, if a remote meter is employed and the antenna current ammeter or common point meter becomes defective, the remote meter can be used to determine operating power pending the return to service of the regular meter.

(e) If conditions beyond the control of the licensee prevent the restoration of the meter to service within the above allowed period, information requested in accordance with §73.3549 may be filed by letter with the FCC in Washington, DC, Attention: Audio Division, Media Bureau, to request additional time as may be required to complete repairs of the defective instrument.

[41 FR 36817, Sept. 1, 1976, as amended at 48 FR 38477, Aug. 24, 1983; 49 FR 49850, Dec. 24, 1984; 50 FR 32416, Aug. 12, 1985; 51 FR 2707, Jan. 21, 1986; 53 FR 2498, Jan. 28, 1988; 63 FR 33876, June 22, 1998; 66 FR 20755, Apr. 25, 2001; 67 FR 13231, Mar. 21, 2002]

(a) Each AM station using a directional antenna must make field strength measurements at the monitoring point locations specified in the instrument of authorization, as often as necessary to ensure that the field at those points does not exceed the values specified in the station authorization. Additionally, stations not having an approved sampling system must make the measurements once each calendar quarter at intervals not exceeding 120 days. The provision of this paragraph supersedes any schedule specified on a station license issued prior to January 1, 1986. The results of the measurements are to be entered into the station log pursuant to the provisions of §73.1820.

(b) Partial proof of performance measurements using the procedures described in §73.154 must be made whenever the licensee has reason to believe that the radiated field may be exceeding the limits for which the station was most recently authorized to operate.

(c) A station may be directed to make a partial proof of performance by the FCC whenever there is an indication that the antenna is not operating as authorized.

[50 FR 47054, Nov. 14, 1985]

(a) Each AM station operating a directional antenna must maintain the indicated relative amplitudes of the antenna monitor currents within 5% of the values specified therein. Directional antenna relative phase currents must be maintained to within ±3 deg. of the values specified on the instrument of authorization.

(b) Whenever the operating parameters of a directional antenna cannot be maintained within the tolerances specified in paragraph (a) of this section, the following procedures will apply:

(1) The licensee shall measure and log every monitoring point at least once for each mode of directional operation. Subsequent variations in operating parameters will require the remeasuring and logging of every monitoring point to assure that the authorized monitoring point limits are not being exceeded.

(2) Provided each monitoring point is within its specified limit, operation may continue for a period up to 30 days before a request for Special Temporary Authority (STA) must be filed, pursuant to paragraph (b)(4) of this section, to operate with parameters at variance from the provisions of paragraph (a) of this section.

(3) If any monitoring point exceeds its specified limit, the licensee must either terminate operation within 3 hours or reduce power in accordance with the applicable provisions of §73.1350(d), in order to eliminate any possibility of interference or excessive radiation in any direction.

(4) If operation pursuant to paragraph (b)(3) of this section is necessary, or before the 30 day period specified in paragraph (b)(2) of this section expires, the licensee must request a Special Temporary Authority (STA) in accordance with §73.1635 to continue operation with parameters at variance and/or with reduced power along with a statement certifying that all monitoring points will be continuously maintained within their specified limits.

(5) The licensee will be permitted 24 hours to accomplish the actions specified in paragraph (b)(1) of this section; provided that, the date and time of the failure to maintain proper operating parameters has been recorded in the station log.

(c) In any other situation in which it might reasonably be anticipated that the operating parameters might vary out of tolerance (such as planned array repairs or adjustment and proofing procedures), the licensee shall, before such activity is undertaken, obtain an STA in accordance with §73.1635 in order to operate with parameters at variance and/or with reduced power as required to maintain all monitoring points within their specified limits.

[50 FR 30946, July 31, 1985, as amended at 60 FR 55480, Nov. 1, 1995; 66 FR 20755, Apr. 25, 2001]

(a) Each AM station permittee authorized to construct a new directional antenna system, must install the sampling system in accordance with the following specifications:

(1) Devices used to extract or sample the current and the transmission line connecting the sampling elements to the antenna monitor must provide accurate and stable signals to the monitor (e.g., rigidly mounted and non-rotatable loops and all system components protected from physical and environmental disturbances).

(2) Sampling lines for directional antennas may be of different lengths provided the phase difference of signals at the monitor are less than 0.5 degrees between the shortest and longest cable lengths due to temperature variations to which the system is exposed.

(3) Other configurations of sampling systems may be used upon demonstration of stable operation to the FCC.

(b) A station having an antenna sampling system constructed according to the specifications given in paragraph (a) of this section may obtain approval of that system by submitting an informal letter request to the FCC in Washington, DC, Attention: Audio Division, Media Bureau. The request for approval, signed by the licensee or authorized representative, must contain sufficient information to show that the sampling system is in compliance with all requirements of paragraph (a) of this section.

Note to paragraph (b): A public notice dated December 9, 1985 giving additional information on approval of antenna sampling systems is available through the Internet at http://www.fcc.gov/mb/audio/decdoc/letter/1985-12-09-sample.html.

(c) In the event that the antenna monitor sampling system is temporarily out of service for repair or replacement, the station may be operated, pending completion of repairs or replacement, for a period not exceeding 120 days without further authority from the FCC if all other operating parameters and the field monitoring point values are within the limits specified on the station authorization.

(d) If the antenna sampling system is modified or components of the sampling system are replaced, the following procedure shall be followed:

(1) Special Temporary Authority (see §73.1635) shall be requested and obtained from the Commission's Audio Division, Media Bureau in Washington to operate with parameters at variance with licensed values pending issuance of a modified license specifying parameters subsequent to modification or replacement of components.

(2) Immediately prior to modification or replacement of components of the sampling system, and after a verification that all monitoring point values and operating parameters are within the limits or tolerances specified in the rules, the following indications must be recorded for each radiation pattern: Final plate current and plate voltage, common point current, antenna monitor phase and current indications, and the field strength at each monitoring point. Subsequent to these modifications or changes the procedure must be repeated.

(3) If monitoring point field strengths or antenna monitor parameters exceed allowable limits following the replacement or modification of that portion of the sampling system above the base of the towers, a partial proof of performance shall be executed in accordance with §73.154 . The partial proof of performance shall be accompanied by common point impedance measurements made in accordance with §73.54.

(4) Request for modification of license shall be submitted to the FCC in Washington, DC, within 30 days of the date of sampling system modification or replacement. Such request shall specify the transmitter plate voltage and plate current, common point current, base currents and their ratios, antenna monitor phase and current indications, and all other data obtained pursuant to this paragraph.

(e) If an existing sampling system is found to be patently of marginal construction, or where the performance of a directional antenna is found to be unsatisfactory, and this deficiency reasonably may be attributed, in whole or in part, to inadequacies in the antenna monitoring system, the FCC may require the reconstruction of the sampling system in accordance with requirements specified above.

[41 FR 7405, Feb. 18, 1976, as amended at 42 FR 24056, May 12, 1977; 44 FR 58731, Oct. 11, 1979; 46 FR 35462, July 8, 1981; 48 FR 38478, Aug. 24, 1983; 48 FR 44805, Sept. 30, 1983; 49 FR 32358, Aug. 14, 1984; 50 FR 47054, Nov. 14, 1985; 51 FR 9965, Mar. 24, 1986; 51 FR 40435, Nov. 7, 1986; 56 FR 64859, Dec. 12, 1991; 63 FR 33876, June 22, 1998; 66 FR 20755, Apr. 25, 2001; 67 FR 13231, Mar. 21, 2002]

(a) Each station using a directional antenna must have in operation at the transmitter site an FCC authorized antenna monitor.

(b) In the event that the antenna monitor sampling system is temporarily out of service for repair or replacement, the station may be operated, pending completion of repairs or replacement, for a period not exceeding 120 days without further authority from the FCC if all other operating parameters, and the field monitoring point values are within the limits specified on the station authorization.

(c) If conditions beyond the control of the licensee prevent the restoration of the monitor to service within the allowed period, an informal letter request in accordance with §73.3549 of the Commission's rules must be filed with the FCC, Attention: Audio Division, Media Bureau in Washington, DC for such additional time as may be required to complete repairs of the defective instrument.

(d) If an authorized antenna monitor is replaced by another antenna monitor, the following procedure shall be followed:

(1) Temporary authority shall be requested and obtained from the Commission in Washington to operate with parameters at variance with licensed values, pending issuance of a modified license specifying new parameters.

(2) Immediately before the replacement of the antenna monitor, after a verification that all monitoring point values and the common point current reading are within the limits or tolerances specified in the rules, the following indications must be recorded for each radiation pattern: Final plate current and plate voltage, common point current, antenna monitor phase and current indications, and the field strength at each monitoring point.

(3) With the new monitor substituted for the old, all indications specified in paragraph (d)(2) of this section, again must be read. If no change has occurred in the indication for any parameter other than the indications of the antenna monitor, the new antenna monitor indications must be deemed to be those reflecting correct array adjustments.

(4) If it cannot be established by the observations required in paragraph (d)(2) of this section that the common point current reading and the monitoring point values are within the tolerances or limits prescribed by the rules and the instrument of authorization, or if the substitution of the new antenna monitor for the old results in changes in these parameters, a partial proof of performance shall be executed and analyzed in accordance with §73.154.

(5) An informal letter request for modification of license shall be submitted to the FCC, Attention: Audio Division, Media Bureau in Washington, DC within 30 days of the date of monitor replacement. Such request shall specify the make, type, and serial number of the replacement monitor, phase and sample current indications, and other data obtained pursuant to this paragraph (d).

(e) The antenna monitor must be calibrated according to the manufacturer's instructions as often as necessary to ensure its proper operation.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, as amended, 1082, as amended; 47 U.S.C. 154, 303. Interpret or apply secs. 301, 303, 307, 48 Stat. 1081, 1082, as amended, 1083, as amended, 47 U.S.C. 301, 303, 307)

[38 FR 1918, Jan. 19, 1973]

Editorial Note:  For Federal Register citations affecting §73.69 see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO Access.

§ 73.72   Operating during the experimental period.

(a) An AM station may operate during the experimental period (the time between midnight and sunrise, local time) on its assigned frequency and with its authorized power for the routine testing and maintenance of its transmitting system, and for conducting experimentation under an experimental authorization, provided no interference is caused to other stations maintaining a regular operating schedule within such period.

(b) No station licensed for “daytime” or “specified hours” of operation may broadcast any regular or scheduled program during this period.

(c) The licensee of an AM station shall operate or refrain from operating its station during the experimental period as directed by the FCC to facilitate frequency measurements or for the determination of interference.

[43 FR 32780, July 28, 1978, as amended at 56 FR 64859, Dec. 12, 1991]

The licensee of each broadcast station is required to satisfy all reasonable complaints of blanketing interference within the 1 V/m contour.

Note: For more detailed instructions concerning operational responsibilities of licensees and permittees under this section, see §73.318 (b), (c) and (d).

[28 FR 13574, Dec. 14, 1963, as amended at 56 FR 64859, Dec. 12, 1991]

(a) To provide maximum uniformity in early morning operation compatible with interference considerations, and to provide for additional service during early evening hours for Class D stations, provisions are made for presunrise service and postsunset service. The permissible power for presunrise or postsunset service authorizations shall not exceed 500 watts, or the authorized daytime or critical hours power (whichever is less). Calculation of the permissible power shall consider only co-channel stations for interference protection purposes.

(b) Presunrise service authorizations (PSRA) permit:

(1) Class D stations operating on Mexican, Bahamian, and Canadian priority Class A clear channels to commence PSRA operation at 6 a.m. local time and to continue such operation until the sunrise times specified in their basic instruments of authorization.

(2) Class D stations situated outside 0.5 mV/m-50% skywave contours of co-channel U.S. Class A stations to commence PSRA operation at 6 a.m. local time and to continue such operation until sunrise times specified in their basic instruments of authorization.

(3) Class D stations located within co-channel 0.5 mV/m-50% skywave contours of U.S. Class A stations, to commence PSRA operation either at 6 a.m. local time, or at sunrise at the nearest Class A station located east of the Class D station (whichever is later), and to continue such operation until the sunrise times specified in their basic instruments of authorization.

(4) Class B and Class D stations on regional channels to commence PSRA operation at 6 a.m. local time and to continue such operation until local sunrise times specified in their basic instruments of authorization.

(c) Extended Daylight Saving Time Pre-Sunrise Authorizations:

(1) Between the first Sunday in April and the end of the month of April, Class D stations will be permitted to conduct pre-sunrise operation beginning at 6 a.m. local time with a maximum power of 500 watts (not to exceed the station's regular daytime or critical hours power), reduced as necessary to comply with the following requirements:

(i) Full protection is to be provided as specified in applicable international agreements.

(ii) Protection is to be provided to the 0.5 mV/m groundwave signals of co-channel U.S. Class A stations; protection to the 0.5 mV/m-50% skywave contours of these stations is not required.

(iii) In determining the protection to be provided, the effect of each interfering signal will be evaluated separately. The presence of interference from other stations will not reduce or eliminate the required protection.

(iv) Notwithstanding the requirements of paragraph (c)(1) (ii) and (iii) of this section, the stations will be permitted to operate with a minimum power of 10 watts unless a lower power is required by international agreement.

(2) The Commission will issue appropriate authorizations to Class D stations not previously eligible to operate during this period. Class D stations authorized to operate during this presunrise period may continue to operate under their current authorization.

(d) Postsunset service authorizations (PSSA) permit:

(1) Class D stations located on Mexican, Bahamian, and Canadian priority Class A clear channels to commence PSSA operation at sunset times specified in their basic instruments of authorization and to continue for two hours after such specified times.

(2) Class D stations situated outside 0.5 mV/m-50% skywave contours of co-channel U.S. Class A stations to commence PSSA operations at sunset times specified in their basic instruments of authorization and to continue for two hours after such specified times.

(3) Class D stations located within co-channel 0.5 mV/m-50% skywave contours of U.S. Class A stations to commence PSSA operation at sunset times specified in their basic instruments of authorization and to continue such operation until two hours past such specified times, or until sunset at the nearest Class A station located west of the Class D station, whichever is earlier. Class D stations located west of the Class A station do not qualify for PSSA operation.

(4) Class D stations on regional channels to commence PSSA operation at sunset times specified on their basic instruments of authorization and to continue such operation until two hours past such specified times.

(e) Procedural Matters. (1) Applications for PSRA and PSSA operation are not required. Instead, the FCC will calculate the periods of such operation and the power to be used pursuant to the provisions of this section and the protection requirements contained in applicable international agreements. Licensees will be notified of permissible power and times of operation. Presunrise and Postsunset service authority permits operation on a secondary basis and does not confer license rights. No request for such authority need be filed. However, stations intending to operate PSRA or PSSA shall submit by letter, signed as specified in §73.3513, the following information:

(i) Licensee name, station call letters and station location,

(ii) Indication as to whether PSRA operation, PSSA operation, or both, is intended by the station,

(iii) A description of the method whereby any necessary power reduction will be achieved.

(2) Upon submission of the required information, such operation may begin without further authority.

(f) Technical criteria. Calculations to determine whether there is objectionable interference will be determined in accordance with the AM Broadcast Technical Standards, §§73.182 through 73.190, and applicable international agreements. Calculations will be performed using daytime antenna systems, or critical hours antenna systems when specified on the license. In performing calculations to determine assigned power and times for commencement of PSRA and PSSA operation, the following standards and criteria will be used:

(1) Class D stations operating in accordance with paragraphs (b)(1), (b)(2), (d)(1), and (d)(2) of this section are required to protect the nighttime 0.5 mV/m-50% skywave contours of co-channel Class A stations. Where a 0.5 mV/m-50% skywave signal from the Class A station is not produced, the 0.5 mV/m groundwave contour shall be protected.

(2) Class D stations are required to fully protect foreign Class B and Class C stations when operating PSRA and PSSA; Class D stations operating PSSA are required to fully protect U.S. Class B stations. For purposes of determining protection, the nighttime RSS limit will be used in the determination of maximum permissible power.

(3) Class D stations operating in accordance with paragraphs (d)(2) and (d)(3) of this section are required to restrict maximum 10% skywave radiation at any point on the daytime 0.1 mV/m groundwave contour of a co-channel Class A station to 25 µV/m. The location of the 0.1 mV/m contour of the Class A station will be determined by use of Figure M3, Estimated Ground Conductivity in the United States. When the 0.1 mV/m contour extends beyond the national boundary, the international boundary shall be considered the 0.1 mV/m contour.

(4) Class B and Class D stations on regional channels operating PSRA and PSSA (Class D only) are required to provide full protection to co-channel foreign Class B and Class C stations.

(5) Class D stations on regional channels operating PSSA beyond 6 p.m. local time are required to fully protect U.S. Class B stations.

(6) The protection that Class D stations on regional channels are required to provide when operating PSSA until 6 p.m. local time is as follows.

(i) For the first half-hour of PSSA operation, protection will be calculated at sunset plus 30 minutes at the site of the Class D station;

(ii) For the second half-hour of PSSA operation, protection will be calculated at sunset plus one hour at the site of the Class D station;

(iii) For the second hour of PSSA operation, protection will be calculated at sunset plus two hours at the site of the Class D station;

(iv) Minimum powers during the period until 6 p.m. local time shall be permitted as follows:

(7) For protection purposes, the nighttime 25% RSS limit will be used in the determination of maximum permissible power.

(g) Calculations made under paragraph (d) of this section may not take outstanding PSRA or PSSA operations into account, nor will the grant of a PSRA or PSSA confer any degree of interference protection on the holder thereof.

(h) Operation under a PSRA or PSSA is not mandatory, and will not be included in determining compliance with the requirements of §73.1740. To the extent actually undertaken, however, presunrise operation will be considered by the FCC in determining overall compliance with past programming representations and station policy concerning commercial matter.

(i) The PSRA or PSSA is secondary to the basic instrument of authorization with which it is to be associated. The PSRA or PSSA may be suspended, modified, or withdrawn by the FCC without prior notice or right to hearing, if necessary to resolve interference conflicts, to implement agreements with foreign governments, or in other circumstances warranting such action. Moreover, the PSRA or PSSA does not extend beyond the term of the basic authorization.

(j) The Commission will periodically recalculate maximum permissible power and times for commencing PSRA and PSSA for each Class D station operating in accordance with paragraph (c) of this section. The Commission will calculate the maximum power at which each individual station may conduct presunrise operations during extended daylight saving time and shall issue conforming authorizations. These original notifications and subsequent notifications should be associated with the station's authorization. Upon notification of new power and time of commencing operation, affected stations shall make necessary adjustments within 30 days.

(k) A PSRA and PSSA does not require compliance with §§73.45, 73.182 and 73.1560 where the operation might otherwise be considered as technically substandard. Further, the requirements of paragraphs (a)(5), (b)(2), (c)(2), and (d)(2) of §73.1215 concerning the scale ranges of transmission system indicating instruments are waived for PSRA and PSSA operation except for the radio frequency ammeters used in determining antenna input power.

(1) A station having an antenna monitor incapable of functioning at the authorized PSRA and PSSA power when using a directional antenna shall take the monitor reading using an unmodulated carrier at the authorized daytime power immediately prior to commencing PSRA or PSSA operations. Special conditions as the FCC may deem appropriate may be included for PSRA or PSSA to insure operation of the transmitter and associated equipment in accordance with all phases of good engineering practice.

[56 FR 64860, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992, as amended at 58 FR 27950, May 12, 1993]

The licensee of an AM broadcast station may use its AM carrier to transmit signals not audible on ordinary consumer receivers, for both broadcast and non-broadcast purposes subject to the following requirements:

(a) Such use does not disrupt or degrade the station's own programs or the programs of other broadcast stations.

(b) AM carrier services that are common carrier in nature are subject to common carrier regulation. Licensees operating such services are required to apply to the FCC for the appropriate authorization and to comply with all policies and rules applicable to the service. Responsibility for making the initial determinations of whether a particular activity is common carriage rests with the AM station licensee. Initial determinations by licensees are subject to FCC examination and may be reviewed at the FCC's discretion. AM carrier services that are private carrier in nature must notify the Licensing Division of the Private Radio Bureau at Gettysburg, Pennsylvania 17325, by letter, prior to initiating service certifying compliance with 47 CFR parts 90 and 94.

(c) AM carrier services are of a secondary nature under the authority of the AM station authorization, and the authority to provide such communications services may not be retained or transferred in any manner separate from the station's authorization. The grant or renewal of an AM station permit or license is not furthered or promoted by proposed or past service. The permittee or licensee must establish that the broadcast operation is in the public interest wholly apart from the subsidiary communications services provided.

(d) The station identification, delayed recording, and sponsor identification announcements required by §§73.1201, 73.1208, and 73.1212 are not applicable to leased communications services transmitted via services that are not of a general broadcast program nature.

(e) The licensee or permittee must retain control over all material transmitted in a broadcast mode via the station's facilities, with the right to reject any material that it deems inappropriate or undesirable.

(f) Installation of the multiplex transmitting equipment must conform with the requirements of §73.1690(e).

[47 FR 25345, June 11, 1982, as amended at 49 FR 34015, Aug. 28, 1984; 51 FR 41629, Nov. 18, 1986; 51 FR 44478, Dec. 10, 1986]

(a) An Am broadcast station may, without specific authority from the FCC, transmit stereophonic programs upon installation of type accepted stereophonic transmitting equipment and the necessary measuring equipment to determine that the stereophonic transmissions conform to the modulation characteristics specified in paragraphs (b) and (c) of this section. Stations transmitting stereophonic programs prior to March 21, 1994 may continue to do so until March 21, 1995 as long as they continue to comply with the rules in effect prior to March 21, 1994.

(b) The following limitations on the transmitted wave must be met to insure compliance with the occupied bandwidth limitations, compatibility with AM receivers using envelope detectors, and any applicable international agreements to which the FCC is a party:

(1) The transmitted wave must meet the occupied bandwidth specifications of §73.44 under all possible conditions of program modulation. Compliance with requirement shall be demonstrated either by the following specific modulation tests or other documented test procedures that are to be fully described in the application for type acceptance and the transmitting equipment instruction manual. (See §2.983(d)(8) and (j)).

(i) Main channel (L+R) under all conditions of amplitude modulations for the stereophonic system but not exceeding amplitude modulation on negative peaks of 100%.

(ii) Stereophonic (L−R) modulated with audio tones of the same amplitude at the transmitter input terminals as in paragraph (b)(i) of this section but with the phase of either the L or R channel reversed.

(iii) Left and Right Channel only, under all conditions of modulation for the stereophonic system in use but not exceeding amplitude modulation on negative peaks of 100%.

(c) Effective on December 20, 1994, stereophonic transmissions shall conform to the following additional modulation characteristics:

(1) The audio response of the main (L+R) channel shall conform to the requirements of the ANSI/EIA–549–1988, NRSC–1 AM Preemphasis/Deemphasis and Broadcast Transmission Bandwidth Specifications (NRSC–1).

(2) The left and right channel audio signals shall conform to frequency response limitations dictated by ANSI/EIA–549–1988.

(3) The stereophonic difference (L−R) information shall be transmitted by varying the phase of the carrier in accordance with the following relationship:

where:

(4) The carrier phase shall advance in a positive direction when a left channel signal causes the transmitter envelope to be modulated in a positive direction. The carrier phase shall likewise retard (negative phase change) when a right channel signal causes the transmitter envelope to be modulated in a positive direction. The phase modulation shall be symmetrical for the condition of difference (L−R) channel information sent without the presence of envelope modulation.

(5) Maximum angular modulation, which occurs on negative peaks of the left or right channel with no signal present on the opposite channel (L(t)=−0.75, R(t)=0, or R(t)=−0.75, L(t)=0) shall not exceed 1.25 radians.

(6) A peak phase modulation of +/−0.785 radians under the condition of difference (L−R) channel modulation and the absence of envelope (L+R) modulation and pilot signal shall represent 100% modulation of the difference channel.

(7) The composite signal shall contain a pilot tone for indication of the presence of stereophonic information. The pilot tone shall consist of a 25 Hz tone, with 3% or less total harmonic distortion and a frequency tolerance of +/− 0.1 H₂, which modulates the carrier phase +/− 0.05 radians peak, corresponding to 5% L−R modulation when no other modulation is present. The injection level shall be 5%, with a tolerance of +1, −1%.

(8) The composite signal shall be described by the following expression:

where:

A=the unmodulated carrier voltage

m=the modulation index

C_sn=the magnitude of the nth term of the sum signal

C_dn=the magnitude of the nth term of the difference signal

ω_sn=the nth order angular velocity of the sum signal

ω_dn=the nth order angular velocity of the difference signal

ω_c=the angular velocity of the carrier

$$

A_sn and B_sn are the n^th sine and cosine coefficients of C_sn

A_dn and B_dn are the n^th sine and cosine coefficients of C_dn

[58 FR 66301, Dec. 20, 1993]

No licensee of an AM broadcast station shall have any arrangement with a network organization which prevents or hinders another station serving substantially the same area from broadcasting the network's programs not taken by the former station, or which prevents or hinders another station serving a substantially different area from broadcasting any program of the network organization: Provided, however, That this section does not prohibit arrangements under which the station is granted first call within its primary service area upon the network's programs. The term “network organization” means any organization originating program material, with or without commercial messages, and furnishing the same to stations interconnected so as to permit simultaneous broadcast by all or some of them. However, arrangements involving only stations under common ownership, or only the rebroadcast by one station or programming from another with no compensation other than a lump-sum payment by the station rebroadcasting, are not considered arrangements with a network organization. The term “arrangement” means any contract, arrangement or understanding, expressed or implied.

[42 FR 16422, Mar. 28, 1977]

(a) For each station employing a directional antenna, all determinations of service provided and interference caused shall be based on the inverse distance fields of the standard radiation pattern for that station. (As applied to nighttime operation the term “standard radiation pattern” shall include the radiation pattern in the horizontal plane, and radiation patterns at angles above this plane.)

(1) Parties submitting directional antenna patterns pursuant to this section and §73.152 (Modified standard pattern) must submit patterns which are tabulated and plotted in units of millivolts per meter at 1 kilometer.

Note: Applications for new stations and for changes (both minor and major) in existing stations must use a standard pattern.

(b) The following data shall be submitted with an application for authority to install a directional antenna:

(1) The standard radiation pattern for the proposed antenna in the horizontal plane, and where pertinent, tabulated values for the azimuthal radiation patterns for angles of elevation up to and including 60 degrees, with a separate section for each increment of 5 degrees.

(i) The standard radiation pattern shall be based on the theoretical radiation pattern. The theoretical radiation pattern shall be calculated in accordance with the following mathematical expression:

where:

The standard radiation pattern shall be constructed in accordance with the following mathematical expression:

where:

E(φ,Θ)_std represents the inverse distance fields at one kilometer which are produced by the directional antenna in the horizontal and vertical planes. E(φ,Θ)_th represents the theoretical inverse distance fields at one kilometer as computed in accordance with Eq. 1, above.

Q is the greater of the following two quantities: 0.025g(Θ) E_rss or 10.0g(Θ) √ P_kW

where:

g(Θ) is the vertical plane distribution factor, f(Θ), for the shortest element in the array (see Eq. 2, above; also see §73.190, Figure 5). If the shortest element has an electrical height in excess of 0.5 wavelength, g(Θ) shall be computed as follows:

$$

E_rss is the root sum square of the amplitudes of the inverse fields of the elements of the array in the horizontal plane, as used in the expression for E(φ,Θ)_th (see Eq. 1, above), and is computed as follows:

$$

P_kW is the nominal station power expressed in kilowatts, see §73.14. If the nominal power is less than one kilowatt, P_kW=1.

(ii) Where the orthogonal addition of the factor Q to E(φ,Θ)_th results in a standard pattern whose minimum fields are lower than those found necessary or desirable, these fields may be increased by appropriate adjustment of the parameters of E(φ,Θ)_th.

(2) All patterns shall be computed for integral multiples of five degrees, beginning with zero degrees representing true north, and, shall be plotted to the largest scale possible on unglazed letter-size paper (main engraving approximately 7' × 10') using only scale divisions and subdivisions of 1,2,2.5, or 5 times 10^nth. The horizontal plane pattern shall be plotted on polar coordinate paper, with the zero degree point corresponding to true north. Patterns for elevation angles above the horizontal plane may be plotted in polar or rectangular coordinates, with the pattern for each angle of elevation on a separate page. Rectangular plots shall begin and end at true north, with all azimuths labelled in increments of not less than 20 degrees. If a rectangular plot is used, the ordinate showing the scale for radiation may be logarithmic. Such patterns for elevation angles above the horizontal plane need be submitted only upon specific request by Commission staff. Minor lobe and null detail occurring between successive patterns for specific angles of elevation need not be submitted. Values of field strength on any pattern less than ten percent of the maximum field strength plotted on that pattern shall be shown on an enlarged scale. Rectangular plots with a logarithmic ordinate need not utilize an expanded scale unless necessary to show clearly the minor lobe and null detail.

(3) The effective (RMS) field strength in the horizontal plane of E(φ,Θ)_std, E(φ,Θ)_th and the root-sum-square (RSS) value of the inverse distance fields of the array elements at 1 kilometer, derived from the equation for E(φ,Θ)_th. These values shall be tabulated on the page on which the horizontal plane pattern is plotted, which shall be specifically labelled as the Standard Horizontal Plane Pattern.

(4) Physical description of the array, showing:

(i) Number of elements.

(ii) Type of each element (i.e., guyed or self-supporting, uniform cross section or tapered (specifying base dimensions), grounded or insulated, etc.)

(iii) Details of top loading, or sectionalizing, if any.

(iv) Height of radiating portion of each element in feet (height above base insulator, or base, if grounded).

(v) Overall height of each element above ground.

(vi) Sketch of antenna site, indicating its dimensions, the location of the antenna elements, thereon, their spacing from each other, and their orientation with respect to each other and to true north, the number and length of the radials in the ground system about each element, the dimensions of ground screens, if any, and bonding between towers and between radial systems.

(5) Electrical description of the array, showing:

(i) Relative amplitudes of the fields of the array elements.

(ii) Relative time phasing of the fields of the array elements in degrees leading [+] or lagging [−].

(iii) Space phasing between elements in degrees.

(iv) Where waiver of the content of this section is requested or upon request of the Commission staff, all assumptions made and the basis therefor, particularly with respect to the electrical height of the elements, current distribution along elements, efficiency of each element, and ground conductivity.

(v) Where waiver of the content of this section is requested, or upon request of the Commission staff, those formulas used for computing E(φ,Θ)_th and E(φ,Θ)_std. Complete tabulation of final computed data used in plotting patterns, including data for the determination of the RMS value of the pattern, and the RSS field of the array.

(6) The values used in specifying the parameters which describe the array must be specified to no greater precision than can be achieved with available monitoring equipment. Use of greater precision raises a rebuttable presumption of instability of the array. Following are acceptable values of precision; greater precision may be used only upon showing that the monitoring equipment to be installed gives accurate readings with the specified precision.

(i) Field Ratio: 3 significant figures.

(ii) Phasing: to the nearest 0.1 degree.

(iii) Orientation (with respect to a common point in the array, or with respect to another tower): to the nearest 0.1 degree.

(iv) Spacing (with respect to a common point in the array, or with respect to another tower): to the nearest 0.1 degree.

(v) Electrical Height (for all parameters listed in Section 73.160): to the nearest 0.1 degree.

(vi) Theoretical RMS (to determine pattern size): 4 significant figures.

(vii) Additional requirements relating to modified standard patterns appear in §73.152(c)(3) and (c)(4).

(7) Any additional information required by the application form.

(c) Sample calculations for the theoretical and standard radiation follow. Assume a five kilowatt (nominal power) station with a theoretical RMS of 685 mV/m at one kilometer. Assume that it is an in-line array consisting of three towers. Assume the following parameters for the towers:

Assume that tower 1 is a typical tower with an electrical height of 120 degrees. Assume that tower 2 is top-loaded in accordance with the method described in §73.160(b)(2) where A is 120 electrical degrees and B is 20 electrical degrees. Assume that tower 3 is sectionalized in accordance with the method described in §73.160(b)(3) where A is 120 electrical degrees, B is 20 electrical degrees, C is 220 electrical degrees, and D is 15 electrical degrees.

The multiplying constant will be 323.6.

Following is a tabulation of part of the theoretical pattern:

If we further assume that the station has a standard pattern, we find that Q, for Θ=0, is 22.36.

Following is a tabulation of part of the standard pattern:

The RMS of the standard pattern in the horizontal plane is 719.63 mV/m at one kilometer.

[36 FR 919, Jan. 20, 1971, as amended at 37 FR 529, Jan. 13, 1972; 41 FR 24134, June 15, 1976; 46 FR 11991, Feb. 12, 1981; 48 FR 24384, June 1, 1983; 51 FR 2707, Jan. 21, 1986; 52 FR 36877, Oct. 1, 1987; 56 FR 64861, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

(a) In addition to the information required by the license application form, the following showing must be submitted to establish, for each mode of directional operation, that the effective measured field strength (RMS) at 1 kilometer (km) is not less than 85 percent of the effective measured field strength (RMS) specified for the standard radiation pattern, or less than that specified in §73.189(b) for the class of station involved, whichever is the higher value, and that the measured field strength at 1 km in any direction does not exceed the field shown in that direction on the standard radiation pattern for that mode of directional operation:

(1) A tabulation of inverse field strengths in the horizontal plane at 1 km, as determined from field strength measurements taken and analyzed in accordance with §73.186, and a statement of the effective measured field strength (RMS). Measurements shall be made in the following directions:

(i) Those specified in the instrument of authorization.

(ii) In major lobes. Generally, one radial is sufficient to establish a major lobe; however, additional radials may be required.

(iii) Along additional radials to establish the shape of the pattern. In the case of a relatively simple directional antenna pattern, a total of six radials is sufficient. If two radials would be more than 90° apart, then an additional radial must be specified within that arc. When more complicated patterns are involved, that is, patterns having several or sharp lobes or nulls, measurements shall be taken along as many as 12 radials to definitely establish the pattern(s). Pattern symmetry may be assumed for complex patterns which might otherwise require measurements on more than 12 radials.

(2) A tabulation of:

(i) The phase difference of the current in each element with respect to the reference element, and whether the current leads (+) or lags (−) the current in the reference element, as indicated by the station's antenna monitor.

(ii) The ratio of the amplitude of the radio frequency current in each element to the current in the reference element, as indicated on the station's antenna monitor.

(3) A monitoring point shall be established on each radial for which the construction permit specifies a limit. The following information shall be supplied for each monitoring point:

(i) Measured field strength.

(ii) An accurate and detailed description of each monitoring point. The description may include, but shall not be limited to, geographic coordinates determined with a Global Positioning System receiver.

(iii) Clear photographs taken with the field strength meter in its measuring position and with the camera so located that its field of view takes in as many pertinent landmarks as possible.

(b) For stations authorized to operate with simple directional antenna systems (e.g., two towers) in the 1605–1705 kHz band, the measurements to support pattern RMS compliance referred to in paragraphs (a)(1)(ii) and (a)(1)(iii) of this section are not required. In such cases, measured radials are required only in the direction of short-spaced allotments, or in directions specifically identified by the Commission.

[36 FR 919, Jan. 20, 1971, as amended at 42 FR 36828, July 18, 1977; 49 FR 23348, June 6, 1984; 50 FR 32416, Aug. 12, 1985; 56 FR 64862, Dec. 12, 1991; 63 FR 33876, June 22, 1998; 66 FR 20756, Apr. 25, 2001]

(a) If, after construction and final adjustment of a directional antenna, a measured inverse distance field in any direction exceeds the field shown on the standard radiation pattern for the pertinent mode of directional operation, an application shall be filed, specifying a modified standard radiation pattern and/or such changes as may be required in operating parameters so that all measured effective fields will be contained within the modified standard radiation pattern. Permittees may also file an application specifying a modified standard radiation pattern, even when measured radiation has not exceeded the standard pattern, in order to allow additional tolerance for monitoring point limits.

(b) If, following a partial proof of performance, a licensee discovers that radiation exceeds the standard pattern on one or more radials because of circumstances beyond the licensee's control, a modified standard pattern may be requested. The licensee shall submit, concurrently, Forms 301–AM and 302–AM. Form 301–AM shall include an exhibit demonstrating that no interference would result from the augmentation. Form 302–AM shall include the results of the partial proof, along with full directional and nondirectional measurements on the radial(s) to be augmented, including close-in points and a determination of the inverse distance field in accordance with §73.186.

(c) Normally, a modified standard pattern is not acceptable at the initial construction permit stage, before a proof-of-performance has been completed. However, in certain cases, where it can be shown that modification is necessary, a modified standard pattern will be acceptable at the initial construction permit stage. Following is a non-inclusive list of items to be considered in determining whether a modification is acceptable at the initial construction permit stage:

(1) When the proposed pattern is essentially the same as an existing pattern at the same antenna site. (e.g., A DA-D station proposing to become a DA–1 station.)

(2) Excessive reradiating structures, which should be shown on a plat of the antenna site and surrounding area.

(3) Other environmental factors; they should be fully described.

(4) Judgment and experience of the engineer preparing the engineering portion of the application. This must be supported with a full discussion of the pertinent factors.

(d) The following general principles shall govern the situations in paragraphs (a), (b), and (c) in this section:

(1) Where a measured field in any direction will exceed the authorized standard pattern, the license application may specify the level at which the input power to the antenna shall be limited to maintain the measured field at a value not in excess of that shown on the standard pattern, and shall specify the common point current corresponding to this power level. This value of common point current will be specified on the license for that station.

(2) Where any excessive field does not result in objectionable interference to another station, a modification of construction permit application may be submitted with a modified standard pattern encompassing all augmented fields. The modified standard pattern shall supersede the previously submitted standard radiation pattern for that station in the pertinent mode of directional operation. Following are the possible methods of creating a modified standard pattern:

(i) The modified pattern may be computed by making the entire pattern larger than the original pattern (i.e., have a higher RMS value) if the measured fields systematically exceed the confines of the original pattern. The larger pattern shall be computed by using a larger multiplying constant, k, in the theoretical pattern equation (Eq. 1) in §73.150(b)(1).

(ii) Where the measured field exceeds the pattern in discrete directions, but objectionable interference does not result, the pattern may be expanded over sectors including these directions. When this “augmentation” is desired, it shall be achieved by application of the following equation:

E(φ,Θ)aug = √{ E(φ,Θ)std}² +A{g(Θ) cos (180 DA/S }²

where:

Note: “A” must be positive, except during the process of converting non-standard patterns to standard patterns pursuant to the Report and Order in Docket No. 21473, and in making minor changes to stations with patterns developed during the conversion. However, even when “A” is negative, “A” cannot be so negative that E(φ,α)aug is less than E(φ,Θ)th at any azimuth or vertical elevation angle.

g(Θ) is defined in §73.150(b)(1)(i).

In the case where there are spans which overlap, the above formula shall be applied repeatedly, once for each augmentation, in ascending order of central azimuth of augmentation, beginning with zero degrees representing true North. Note that, when spans overlap, there will be, in effect, an augmentation of an augmentation. And, if the span of an earlier augmentation overlaps the central azimuth of a later augmentation, the value of “A” for the later augmentation will be different than the value of “A” without the overlap of the earlier span.

(iii) A combination of paragraphs (d)(2)(i) and (d)(2)(ii), of this section, with (d)(2)(i) being applied before (d)(2)(ii) is applied.

(iv) Where augmentation is allowable under the terms of this section, the requested amount of augmentation shall be centered upon the measured radial and shall not exceed the following:

(A) The actual measured inverse distance field value, where the radial does not involve a required monitoring point.

(B) 120% of the actual measured inverse field value, where the radial has a monitoring point required by the instrument of authorization.

Whereas some pattern smoothing can be accommodated, the extent of the requested span(s) shall be minimized and in no case shall a requested augmentation span extend to a radial azimuth for which the analyzed measurement data does not show a need for augmentation.

(3) A Modified Standard Pattern shall be specifically labeled as such, and shall be plotted in accordance with the requirements of paragraph (b)(2) of §73.150. The effective (RMS) field strength in the horizontal plane of E(φ,α)std, E(φ,α)th, and the root sum square (RSS) value of the inverse fields of the array elements (derived from the equation for E(φ,α)th), shall be tabulated on the page on which the horizontal plane pattern is plotted. Where sector augmentation has been employed in designing the modified pattern, the direction of maximum augmentation (i.e., the central azimuth of augmentation) shall be indicated on the horizontal plane pattern for each augmented sector, and the limits of each sector shall also be shown. Field values within an augmented sector, computed prior to augmentation, shall be depicted by a broken line.

(4) There shall be submitted, for each modified standard pattern, complete tabulations of final computed data used in plotting the pattern. In addition, for each augmented sector, the central azimuth of augmentation, span, and radiation at the central azimuth of augmentation (E(φ,α)aug) shall be tabulated.

(5) The parameters used in computing the modified standard pattern shall be specified with realistic precision. Following is a list of the maximum acceptable precision:

(i) Central Azimuth of Augmentation: to the nearest 0.1 degree.

(ii) Span: to the nearest 0.1 degree.

(iii) Radiation at Central Azimuth of Augmentation: 4 significant figures.

(e) Sample calculations for a modified standard pattern follow. First, assume the existing standard pattern in §73.150(c). Then, assume the following augmentation parameters:

Following is a tabulation of part of the modified standard pattern:

[46 FR 11992, Feb. 12, 1981, as amended at 56 FR 64862, Dec. 12, 1991; 66 FR 20756, Apr. 25, 2001]

In the determination of interference, groundwave field strength measurements will take precedence over theoretical values, provided such measurements are properly taken and presented. When measurements of groundwave signal strength are presented, they shall be sufficiently complete in accordance with §73.186 to determine the field strength at 1 mile in the pertinent directions for that station. The antenna resistance measurements required by §73.186 need not be taken or submitted.

[44 FR 36037, June 20, 1979, as amended at 56 FR 64862, Dec. 12, 1991]

(a) A partial proof of performance consists of at least 8 field strength measurements made on each of the radials that includes a monitoring point. If the directional pattern has fewer than 4 monitored radials, the partial proof shall include measurements on those radials from the latest complete proof of performance which are adjacent to the monitored radials.

(b) The measurements are to be made within 3 to 15 kilometers from the center of the antenna array. When a monitoring point as designated on the station authorization lies on a particular radial, one of the measurements must be made at that point. One of the following methods shall be used for the partial proof:

(1) Measurement points shall be selected from the points measured in latest full proof of performance provided that the points can be identified with reasonable certainty, and that land development or other factors have not significantly altered propagation characteristics since the last full proof. At each point, the licensee shall measure directional field strength for comparison to either the directional or the nondirectional field strength measured at that point in the last full proof.

(2) In the event that a meaningful comparison to full proof measurements cannot be made, the licensee shall measure both directional and nondirectional field strength at eight points on each radial. The points need not be limited to those measured in the last full proof of performance.

(c) The results of the measurements are to be analyzed as follows. Either the arithmetic average or the logarithmic average of the ratios of the field strength at each measurement point to the corresponding field strength in the most recent complete proof of performance shall be used to establish the inverse distance fields. (The logarithmic average for each radial is the antilogarithm of the mean of the logarithms of the ratios of field strength (new to old) for each measurement location along a given radial). When new nondirectional measurements are used as the reference, as described in paragraph (b)(2) of this section, either the arithmetic or logarithmic averages of directional to nondirectional field strength on each radial shall be used in conjunction with the measured nondirectional field from the last proof to establish the inverse distance field.

(d) The result of the most recent partial proof of performance measurements and analysis is to be retained in the station records available to the FCC upon request. Maps showing new measurement points, i.e., points not measured in the last full proof, shall be associated with the partial proof in the station's records, and shall be provided to the FCC upon request.

[66 FR 20756, Apr. 25, 2001]

(a) The licensee of a station using a directional antenna during daytime or nighttime hours may, without further authority, operate during daytime hours with the licensed nighttime directional facilities or with a nondirectional antenna when conducting monitoring point field strength measurements or antenna proof of performance measurements.

(b) Operation pursuant to this section is subject to the following conditions:

(1) No harmful interference will be caused to any other station.

(2) The FCC may notify the licensee to modify or cease such operation to resolve interference complaints or when such action may appear to be in the public interest, convenience and necessity.

(3) Such operation shall be undertaken only for the purpose of taking monitoring point field strength measurements or antenna proof of performance measurements, and shall be restricted to the minimum time required to accomplish the measurements.

(4) Operating power in the nondirectional mode shall be adjusted to the same power as was utilized for the most recent nondirectional proof of performance covering the licensed facilities.

[50 FR 30947, July 31, 1985]

(a) When a licensee of a station using a directional antenna system finds that a field monitoring point, as specified on the station authorization, is no longer accessible or is unsuitable because of nearby construction or other disturbances to the measured field, an application to change the monitoring point location, including FCC Form 302–AM, is to be promptly submitted to the FCC in Washington, DC.

(1) If the monitoring point has become inaccessible or otherwise unsuitable, but there has been no significant construction or other change in the vicinity of the monitoring point which may affect field strength readings, the licensee shall select a new monitoring point from the points measured in the last full proof of performance. A recent field strength measurement at the new monitoring point shall also be provided.

(2) Alternatively, if changes in the electromagnetic environment have affected field strength readings at the monitoring point, the licensee shall submit the results of a partial proof of performance, analyzed in accordance with §73.154, on the affected radial.

(3) The licensee shall submit an accurate, written description of the new monitoring point in relation to nearby permanent landmarks.

(4) The licensee shall submit a photograph showing the new monitoring point in relation to nearby permanent landmarks that can be used in locating the point accurately at all times throughout the year. Do not use seasonal or temporary features in either the written descriptions or photographs as landmarks for locating field points.

(b) When the description of the monitoring point as shown on the station license is no longer correct due to road or building construction or other changes, the licensee must prepare and file with the FCC, in Washington, DC, a request for a corrected station license showing the new monitoring point description. The request shall include the information specified in paragraphs (a)(3) and (a)(4) of this section, and a copy of the station's current license. A copy of the description is to be posted with the existing station license.

[66 FR 20757, Apr. 25, 2001]

(a) The vertical plane radiation characteristics show the relative field being radiated at a given vertical angle, with respect to the horizontal plane. The vertical angle, represented as Θ, is 0 degrees in the horizontal plane, and 90 degrees when perpendicular to the horizontal plane. The vertical plane radiation characteristic is referred to as f(Θ). The generic formula for f(Θ) is:

f(Θ)=E(Θ)/E(O)

where:

(b) Listed below are formulas for f(Θ) for several common towers.

(1) For a typical tower, which is not top-loaded or sectionalized, the following formula shall be used:

where:

(2) For a top-loaded tower, the following formula shall be used:

where:

See Figure 1 of this section.

(3) For a sectionalized tower, the following formula shall be used:

where:

See Figure 2 of this section.

(c) One of the above f(Θ) formulas must be used in computing radiation in the vertical plane, unless the applicant submits a special formula for a particular type of antenna. If a special formula is submitted, it must be accompanied by a complete derivation and sample calculations. Submission of values for f(Θ) only in a tabular or graphical format (i.e., without a formula) is not acceptable.

(d) Following are sample calculations. (The number of significant figures shown here should not be interpreted as a limitation on the number of significant figures used in actual calculations.)

(1) For a typical tower, as described in paragraph (b)(1) of this section, assume that G=120 electrical degrees:

(2) For a top-loaded tower, as described in paragraph (b)(2) of this section, assume A=120 electrical degrees, B=20 electrical degrees, and G=140 electrical degrees, (120+20):

(3) For a sectionalized tower, as described in paragraph (b)(3) of this section, assume A=120 electrical degrees, B=20 electrical degrees, C=220 electrical degrees, D=15 electrical degrees, G=140 electrical degrees (120+20), H=235 electrical degrees (220+15), and Δ=115 electrical degrees (235−120):

[46 FR 11993, Feb. 12, 1981]

(a) Sections 73.21 to 73.37, inclusive, govern allocation of facilities in the AM broadcast band 535–1705 kHz. §73.21 establishes three classes of channels in this band, namely, clear, regional and local. The classes and power of AM broadcast stations which will be assigned to the various channels are set forth in §73.21. The classifications of the AM broadcast stations are as follows:

(1) Class A stations operate on clear channels with powers no less than 10kW nor greater than 50 kW. These stations are designed to render primary and secondary service over an extended area, with their primary services areas protected from objectionable interference from other stations on the same and adjacent channels. Their secondary service areas are protected from objectionable interference from co-channel stations. For purposes of protection, Class A stations may be divided into two groups, those located in any of the contiguous 48 States and those located in Alaska in accordance with §73.25.

(i) The mainland U.S. Class A stations are those assigned to the channels allocated by §73.25. The power of these stations shall be 50 kW. The Class A stations in this group are afforded protection as follows:

(A) Daytime. To the 0.1 mV/m groundwave contour from stations on the same channel, and to the 0.5 mV/m groundwave contour from stations on adjacent channels.

(B) Nighttime. To the 0.5 mV/m-50% skywave contour from stations on the same channels.

(ii) Class A stations in Alaska operate on the channels allocated by §73.25 with a minimum power of 10 kW, a maximum power of 50 kW, and an antenna efficiency of 282 mV/m/kW at 1 kilometer. Stations operating on these channels in Alaska which have not been designated as Class A stations in response to licensee request will continue to be considered as Class B stations. During daytime hours a Class A station in Alaska is protected to the 100 µV/m groundwave contour from co-channel stations. During nighttime hours, a Class A station in Alaska is protected to the 100 µV/m-50 percent skywave contour from co-channel stations. The 0.5 mV/m groundwave contour is protected both daytime and nighttime from stations on adjacent channels.

Note: In the Report and Order in MM Docket No. 83–807, the Commission designated 15 stations operating on U.S. clear channels as Alaskan Class A stations. Eleven of these stations already have Alaskan Class A facilities and are to be protected accordingly. Permanent designation of the other four stations as Alaskan Class A is conditioned on their constructing minimum Alaskan Class A facilities no later than December 31, 1989. Until that date or until such facilities are obtained, these four stations shall be temporarily designated as Alaskan Class A stations, and calculations involving these stations should be based on existing facilities but with an assumed power of 10 kW. Thereafter, these stations are to be protected based on their actual Alaskan Class A facilities. If any of these stations does not obtain Alaskan Class A facilities in the period specified, it is to be protected as a Class B station based on its actual facilities. These four stations may increase power to 10 kW without regard to the impact on co-channel Class B stations. However, power increases by these stations above 10 kW (or by existing Alaskan Class A stations beyond their current power level) are subject to applicable protection requirements for co-channel Class B stations. Other stations not on the original list but which meet applicable requirements may obtain Alaskan Class A status by seeking such designation from the Commission. If a power increase or other change in facilities by a station not on the original list is required to obtain minimum Alaskan Class A facilities, any such application shall meet the interference protection requirements applicable to an Alaskan Class A proposal on the channel.

(2) Class B stations are stations which operate on clear and regional channels with powers not less than 0.25 kW nor more than 50 kW. These stations render primary service only, the area of which depends on their geographical location, power, and frequency. It is recommended that Class B stations be located so that the interference received from other stations will not limit the service area to a groundwave contour value greater than 2.0 mV/m nighttime and to the 0.5 mV/m groundwave contour daytime, which are the values for the mutual protection between this class of stations and other stations of the same class.

Note: See §§73.21(b)(1) and 73.26(b) concerning power restrictions and classifications relative to Class B, Class C, and Class D stations in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. Stations in the above-named places that are reclassified from Class C to Class B stations under §73.26(b) shall not be authorized to increase power to levels that would increase the nighttime interference-free limit of co-channel Class C stations in the conterminous United States.

(3) Class C stations operate on local channels, normally rendering primary service to a community and the suburban or rural areas immediately contiguous thereto, with powers not less than 0.25 kW, nor more than 1 kW, except as provided in §73.21(c)(1). Such stations are normally protected to the daytime 0.5 mV/m contour. On local channels the separation required for the daytime protection shall also determine the nighttime separation. Where directional antennas are employed daytime by Class C stations operating with more than 0.25 kW power, the separations required shall in no case be less than those necessary to afford protection, assuming nondirectional operation with 0.25 kW. In no case will 0.25 kW or greater nighttime power be authorized to a station unable to operate nondirectionally with a power of 0.25 kW during daytime hours. The actual nighttime limitation will be calculated. For nighttime protection purposes, Class C stations in the 48 contiguous United States may assume that stations in Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands operating on 1230, 1240, 1340, 1400, 1450, and 1490 kHz are Class C stations.

(4) Class D stations operate on clear and regional channels with daytime powers of not less than 0.25 kW (or equivalent RMS field of 141 mV/m at one kilometer if less than 0.25 kW) and not more than 50 kW. Class D stations that have previously received nighttime authority operate with powers of less than 0.25 kW (or equivalent RMS fields of less than 141 mV/m at one kilometer) are not required to provide nighttime coverage in accordance with §73.24(j) and are not protected from interference during nighttime hours. Such nighttime authority is permitted on the basis of full nighttime protection being afforded to all Class A and Class B stations.

(b) When a station is already limited by interference from other stations to a contour value greater than that normally protected for its class, the individual received limits shall be the established standard for such station with respect to interference from each other station.

(c) The four classes of AM broadcast stations have in general three types of service areas, i.e., primary, secondary and intermittent. (See §73.14 for the definitions of primary, secondary, and intermittent service areas.) Class A stations render service to all three areas. Class B stations render service to a primary area but the secondary and intermittent service areas may be materially limited or destroyed due to interference from other stations, depending on the station assignments involved. Class C and Class D stations usually have only primary service areas. Interference from other stations may limit intermittent service areas and generally prevents any secondary service to those stations which operate at night. Complete intermittent service may still be obtained in many cases depending on the station assignments involved.

(d) The groundwave signal strength required to render primary service is 2 mV/m for communities with populations of 2,500 or more and 0.5 mV/m for communities with populations of less than 2,500. See §73.184 for curves showing distance to various groundwave field strength contours for different frequencies and ground conductivities, and also see §73.183, “Groundwave signals.”

(e) A Class C station may be authorized to operate with a directional antenna during daytime hours providing the power is at least 0.25 kW. In computing the degrees of protection which such antenna will afford, the radiation produced by the directional antenna system will be assumed to be no less, in any direction, than that which would result from non-directional operation using a single element of the directional array, with 0.25 kW.

(f) All classes of broadcast stations have primary service areas subject to limitation by fading and noise, and interference from other stations to the contours set out for each class of station.

(g) Secondary service is provided during nighttime hours in areas where the skywave field strength, 50% or more of the time, is 0.5 mV/m or greater (0.1 mV/m in Alaska). Satisfactory secondary service to cities is not considered possible unless the field strength of the skywave signal approaches or exceeds the value of the groundwave field strength that is required for primary service. Secondary service is subject to some interference and extensive fading whereas the primary service area of a station is subject to no objectionable interference or fading. Only Class A stations are assigned on the basis of rendering secondary service.

Note: Standards have not been established for objectionable fading because of the relationship to receiver characteristics. Selective fading causes audio distortion and signal strength reduction below the noise level, objectionable characteristics inherent in many modern receivers. The AVC circuits in the better designed receivers generally maintain the audio output at a sufficiently constant level to permit satisfactory reception during most fading conditions.

(h) Intermittent service is rendered by the groundwave and begins at the outer boundary of the primary service area and extends to a distance where the signal strength decreases to a value that is too low to provide any service. This may be as low as a few µV/m in certain areas and as high as several millivolts per meter in other areas of high noise level, interference from other stations, or objectionable fading at night. The intermittent service area may vary widely from day to night and generally varies over shorter intervals of time. Only Class A stations are protected from interference from other stations to the intermittent service area.

(i) Broadcast stations are licensed to operate unlimited time, limited time, daytime, share time, and specified hours. (See §§73.1710, 73.1725, 73.1720, 73.1715, and 73.1730.) Applications for new stations shall specify unlimited time operation only.

(j) Section 73.24 sets out the general requirements for modifying the facilities of a licensed station and for establishing a new station. Sections 73.24(b) and 73.37 include interference related provisions that be considered in connection with an application to modify the facilities of an existing station or to establish a new station. Section 73.30 describes the procedural steps required to receive an authorization to operate in the 1605–1705 kHz band.

(k) Objectionable nighttime interference from a broadcast station occurs when, at a specified field strength contour with respect to the desired station, the field strength of an undesired station (co-channel or first adjacent channel, after application of proper protection ratio) exceeds for 10% or more of the time the values set forth in these standards. The value derived from the root-sum-square of all interference contributions represents the extent of a station's interference-free coverage.

(1) With respect to the root-sum-square (RSS) values of interfering field strengths referred to in this section, calculation of nighttime interference-free service is accomplished by considering the signals on the three channels of concern (co- and first adjacencies) in order of decreasing magnitude, adding the squares of the values and extracting the square root of the sum, excluding those signals which are less than 50% of the RSS values of the higher signals already included.

(2) With respect to the root-sum-square values of interfering field strengths referred to in this section, calculation of nighttime interference for non-coverage purposes is accomplished by considering the signals on the three channels of concern (co- and first adjacencies) in order of decreasing magnitude, adding the squares of the values and extracting the square root of the sum, excluding those signals which are less than 25% of the RSS values of the higher signals already included.

(3) With respect to the root-sum-square values of interfering field strengths referred to in this section, calculation is accomplished by considering the signals on the three channels of concern (co- and first adjacencies) in order of decreasing magnitude, adding the squares of the values and extracting the square root of the sum. The 0% exclusion method applies only to the determination of an improvement factor value for evaluating a station's eligibility for migration to the band 1605–1705 kHz.

(4) The RSS value will not be considered to be increased when a new interfering signal is added which is less than the appropriate exclusion percentage as applied to the RSS value of the interference from existing stations, and which at the same time is not greater than the smallest signal included in the RSS value of interference from existing stations.

(5) It is recognized that application of the above “50% exclusion” method (or any exclusion method using a per cent value greater than zero) of calculating the RSS interference may result in some cases in anomalies wherein the addition of a new interfering signal or the increase in value of an existing interfering signal will cause the exclusion of a previously included signal and may cause a decrease in the calculated RSS value of interference. In order to provide the Commission with more realistic information regarding gains and losses in service (as a basis for determination of the relative merits of a proposed operation) the following alternate method for calculating the proposed RSS values of interference will be employed wherever applicable.

(6) In the cases where it is proposed to add a new interfering signal which is not less than 50% (or 25%, depending on which study is being performed) of the RSS value of interference from existing stations or which is greater that the smallest signal already included to obtain this RSS value, the RSS limitation after addition of the new signal shall be calculated without excluding any signal previously included. Similarly, in cases where it is proposed to increase the value of one of the existing interfering signals which has been included in the RSS value, the RSS limitation after the increase shall be calculated without excluding the interference from any source previously included.

(7) If the new or increased signal proposed in such cases is ultimately authorized, the RSS values of interference to other stations affected will thereafter be calculated by the “50% exclusion” (or 25% exclusion, depending on which study is being performed) method without regard to this alternate method of calculation.

(8) Examples of RSS interference calculations:

(i) Existing interferences:

Station No. 1—1.00 mV/m.

(ii) Station A receives interferences from:

Station No. 1—1.00 mV/m.

(iii) Station A receives interferences from:

Station No. 1—1.00 mV/m.

Note: The principles demonstrated in the previous examples for the calculation of the 50% exclusion method also apply to calculations using the 25% exclusion method after appropriate adjustment.

(l) Objectionable nighttime interference from a station shall be considered to exist to a station when, at the field strength contour specified in paragraph (q) of this section with respect to the class to which the station belongs, the field strength of an interfering station operating on the same channel or on a first adjacent channel after signal adjustment using the proper protection ratio, exceeds for 10% or more of the time the value of the permissible interfering signal set forth opposite such class in paragraph (q) of this section.

(m) For the purpose of estimating the coverage and the interfering effects of stations in the absence of field strength measurements, use shall be made of Figure 8 of §73.190, which describes the estimated effective field (for 1 kW power input) of simple vertical omnidirectional antennas of various heights with ground systems having at least 120 quarter-wavelength radials. Certain approximations, based on the curve or other appropriate theory, may be made when other than such antennas and ground systems are employed, but in any event the effective field to be employed shall not be less than the following:

(n) The existence or absence of objectionable groundwave interference from stations on the same or adjacent channels shall be determined by actual measurements made in accordance with the method described in §73.186, or in the absence of such measurements, by reference to the propagation curves of §73.184. The existence or absence of objectionable interference due to skywave propagation shall be determined by reference to Formula 2 in §73.190.

(o) Computation of Skywave Field Strength Values:

(1) Fifty Percent Skywave Field Strength Values (Clear Channel). In computing the fifty percent skywave field strength values of a Class A clear channel station, use shall be made of Formula 1 of §73.190, entitled “Skywave Field Strength” for 50 percent of the time.

(2) Ten Percent Skywave Field Strength Values. In computing the 10% skywave field strength for stations on a single signal or an RSS basis, Formula 2 in §73.190 shall be used.

(3) Determination of Angles of Departure. In calculating skywave field strength for stations on all channels, the pertinent vertical angle shall be determined by use of the formula in §73.190(d).

(p) The distance to any specified groundwave field strength contour for any frequency may be determined from the appropriate curves in §73.184 entitled “Ground Wave Field Strength vs. Distance.”

(q) Normally protected service contours and permissible interference signals for broadcast stations are as follows (for Class A stations, see also paragraph (a) of this section):

(r) The following table of logarithmic expressions is to be used as required for determining the minimum permissible ratio of the field strength of a desired to an undesired signal. This table shall be used in conjunction with the protected contours specified in paragraph (q) of this section.

(s) Two stations, one with a frequency twice of the other, should not be assigned in the same groundwave service area unless special precautions are taken to avoid interference from the second harmonic of the station operating on the lower frequency. Additionally, in selecting a frequency, consideration should be given to the fact that occasionally the frequency assignment of two stations in the same area may bear such a relation to the intermediate frequency of some broadcast receivers as to cause “image” interference, However, since this can usually be rectified by readjustment of the intermediate frequency of such receivers, the Commission, in general, will not take this kind of interference into consideration when authorizing stations.

(t) The groundwave service of two stations operating with synchronized carriers and broadcasting identical programs will be subject to some distortion in areas where the signals from the two stations are of comparable strength. For the purpose of estimating coverage of such stations, areas in which the signal ratio is between 1:2 and 2:1 will not be considered as receiving satisfactory service.

Note: Two stations are considered to be operated synchronously when the carriers are maintained within 0.2 Hz of each other and they transmit identical program s.

[56 FR 64862, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992, as amended at 58 FR 27950, May 12, 1993]

(a) Interference that may be caused by a proposed assignment or an existing assignment during daytime hours should be determined, when possible, by measurements on the frequency involved or on another frequency over the same terrain and by means for the curves in §73.184 entitled “Ground Wave Field Strength versus Distance.”

Note: Groundwave field strength measurements will not be accepted or considered for the purpose of establishing that interference to a station in a foreign country other than Canada, or that the field strength at the border thereof, would be less than indicated by the use of the ground conductivity maps and engineering standards contained in this part and applicable international agreements. Satisfactory groundwave measurements offered for the purpose of demonstrating values of conductivity other than those shown by Figure M3 in problems involving protection of Canadian stations will be considered only if, after review thereof, the appropriate agency of the Canadian government notifies the Commission that they are acceptable for such purpose.

(b)(1) In all cases where measurements taken in accordance with the requirements are not available, the groundwave strength must be determined by means of the pertinent map of ground conductivity and the groundwave curves of field strength versus distance. The conductivity of a given terrain may be determined by measurements of any broadcast signal traversing the terrain involved. Figure M3 (See Note 1) shows the conductivity throughout the United States by general areas of reasonably uniform conductivity. When it is clear that only one conductivity value is involved, Figure R3 of §73.190, may be used. It is a replica of Figure M3, and is contained in these standards. In all other situations Figure M3 must be employed. It is recognized that in areas of limited size or over a particular path, the conductivity may vary widely from the values given; therefore, these maps are to be used only when accurate and acceptable measurements have not been made.

(2) For determinations of interference and service requiring a knowledge of ground conductivities in other countries, the ground conductivity maps comprising Appendix 1 to Annex 2 of each of the following international agreements may be used:

(i) For Canada, the U.S.-Canada AM Agreement, 1984;

(ii) For Mexico, the U.S.-Mexico AM Agreement, 1986; and

(iii) For other Western Hemisphere countries, the Regional Agreement for the Medium Frequency Broadcasting Service in Region 2.

Where different conductivities appear in the maps of two countries on opposite sides of the border, such differences are to be considered as real, even if they are not explained by geophysical cleavages.

(c) Example of determining interference by the graphs in §73.184:

It is desired to determine whether objectionable interference exists between a proposed 5 kW Class B station on 990 kHz and an existing 1 kW Class B station on first adjacent channel, 1000 kHz. The distance between the two stations is 260 kilometers and both stations operate nondirectionally with antenna systems that produce a horizontal effective field of 282 in mV/m at one kilometer. (See §73.185 regarding use of directional antennas.) The ground conductivity at the site of each station and along the intervening terrain is 6 mS/m. The protection to Class B stations during daytime is to the 500 µV/m (0.5 Vm) contour using a 6 dB protection factor. The distance to the 500 µV/m groundwave contour of the 1 kW station is determined by the use of the appropriate curve in §73.184. Since the curve is plotted for 100 mV/m at a 1 kilometer, to find the distance of the 0.5 mV/m contour of the 1 kw station, it is necessary to determine the distance to the 0.1773 m/Vm contour.

(d) Where a signal traverses a path over which different conductivities exist, the distance to a particular groundwave field strength contour shall be determined by the use of the equivalent distance method. Reasonably accurate results may be expected in determining field strengths at a distance from the antenna by application of the equivalent distance method when the unattenuated field of the antenna, the various ground conductivities and the location of discontinuities are known. This method considers a wave to be propagated across a given conductivity according to the curve for a homogeneous earth of that conductivity. When the wave crosses from a region of one conductivity into a region of a second conductivity, the equivalent distance of the receiving point from the transmitter changes abruptly but the field strength does not. From a point just inside the second region the transmitter appears to be at that distance where, on the curve for a homogeneous earth of the second conductivity, the field strength equals the value that occurred just across the boundary in the first region. Thus the equivalent distance from the receiving point to the transmitter may be either greater or less than the actual distance. An imaginary transmitter is considered to exist at that equivalent distance. This technique is not intended to be used as a means of evaluating unattenuated field or ground conductivity by the analysis of measured data. The method to be employed for such determinations is set out in §73.186.

(e) Example of the use of the equivalent distance method;

It is desired to determine the distance to the 0.5 mV/m and 0.025 mV/m contours of a station on a frequency of 1000 kHz with an inverse distance field of 100 mV/m at one kilometer being radiated over a path having a conductivity of 10 mS/m for a distance of 20 kilometers, 5 mS/m for the next 30 kilometers and 15 mS/m thereafter. Using the appropriate curve in §73.184, Graph 12, at a distance of 20 kilometers on the curve for 10 mS/m, the field strength is found to be 2.84 mV/m. On the 5mS/m curve, the equivalent distance to this field strength is 14.92 kilometers, which is 5.08 (20−14.92 kilometers nearer to the transmitter. Continuing on the propagation curve, the distance to a field strength of 0.5 mV/m is found to be 36.11 kilometers.

[28 FR 13574, Dec. 14, 1963, as amended at 44 FR 36037, June 20, 1979; 48 FR 9011, Mar. 3, 1983; 50 FR 18822, May 2, 1985; 50 FR 24522, June 11, 1985; 51 FR 9965, Mar. 24, 1986; 54 FR 39736, Sept. 28, 1989; 56 FR 64866, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

(a) Graphs 1 to 20 show, for each of 20 frequencies, the computed values of groundwave field strength as a function of groundwave conductivity and distance from the source of radiation. The groundwave field strength is considered to be that part of the vertical component of the electric field which has not been reflected from the ionosphere nor from the troposphere. These 20 families of curves are plotted on log-log graph paper and each is to be used for the range of frequencies shown thereon. Computations are based on a dielectric constant of the ground (referred to air as unity) equal to 15 for land and 80 for sea water and for the ground conductivities (expressed in mS/m) given on the curves. The curves show the variation of the groundwave field strength with distance to be expected for transmission from a vertical antenna at the surface of a uniformly conducting spherical earth with the groundwave constants shown on the curves. The curves are for an antenna power of such efficiency and current distribution that the inverse distance (unattenuated) field is 100 mV/m at 1 kilometer. The curves are valid for distances that are large compared to the dimensions of the antenna for other than short vertical antennas.

(b) The inverse distance field (100 mV/m divided by the distance in kilometers) corresponds to the groundwave field intensity to be expected from an antenna with the same radiation efficiency when it is located over a perfectly conducting earth. To determine the value of the groundwave field intensity corresponding to a value of inverse distance field other than 100 mV/m at 1 kilometer, multiply the field strength as given on these graphs by the desired value of inverse distance field at 1 kilometer divided by 100; for example, to determine the groundwave field strength for a station with an inverse distance field of 2700 mV/m at 1 kilometer, simply multiply the values given on the charts by 27. The value of the inverse distance field to be used for a particular antenna depends upon the power input to the antenna, the nature of the ground in the neighborhood of the antenna, and the geometry of the antenna. For methods of calculating the interrelations between these variables and the inverse distance field, see “The Propagation of Radio Waves Over the Surface of the Earth and in the Upper Atmosphere,” Part II, by Mr. K.A. Norton, Proc. I.R.E., Vol. 25, September 1937, pp. 1203–1237.

Note: The computed values of field strength versus distance used to plot Graphs 1 to 20 are available in tabular form. For information on obtaining copies of these tabulations call or write the Consumer Affairs Office, Federal Communications Commission, Washington, DC 20554, (202) 632–7000.

(c) Provided the value of the dielectric constant is near 15, the ground conductivity curves of Graphs 1 to 20 may be compared with actual field strength measurement data to determine the appropriate values of the ground conductivity and the inverse distance field strength at 1 kilometer. This is accomplished by plotting the measured field strengths on transparent log-log graph paper similar to that used for Graphs 1 to 20 and superimposing the plotted graph over the Graph corresponding to the frequency of the station measured. The plotted graph is then shifted vertically until the plotted measurement data is best aligned with one of the conductivity curves on the Graph; the intersection of the inverse distance line on the Graph with the 1 kilometer abscissa on the plotted graph determines the inverse distance field strength at 1 kilometer. For other values of dielectric constant, the following procedure may be used to determine the dielectric constant of the ground, the ground conductivity and the inverse distance field strength at 1 kilometer. Graph 21 gives the relative values of groundwave field strength over a plane earth as a function of the numerical distance p and phase angle b. On graph paper with coordinates similar to those of Graph 21, plot the measured values of field strength as ordinates versus the corresponding distances from the antenna in kilometers as abscissae. The data should be plotted only for distances greater than one wavelength (or, when this is greater, five times the vertical height of the antenna in the case of a nondirectional antenna or 10 times the spacing between the elements of a directional antenna) and for distances less than 80f^1/3 MHz kilometers (i.e., 80 kilometers at 1 MHz). Then, using a light box, place the plotted graph over Graph 21 and shift the plotted graph vertically and horizontally (making sure that the vertical lines on both sheets are parallel) until the best fit with the data is obtained with one of the curves on Graph 21. When the two sheets are properly lined up, the value of the field strength corresponding to the intersection of the inverse distance line of Graph 21 with the 1 kilometer abscissa on the data sheet is the inverse distance field strength at 1 kilometer, and the values of the numerical distance at 1 kilometer, p₁, and of b are also determined. Knowing the values of b and p₁ (the numerical distance at one kilometer), we may substitute in the following approximate values of the ground conductivity and dielectric constant.

(R/λ)₁=Number of wavelengths in 1 kilometer,

                   *                 *                 *                 *                 *

f_MHz=frequency expressed in megahertz,

ε=dielectric constant on the ground referred to air as unity.

First solve for χ by substituting the known values of p₁, (R/λ)₁, and cos b in equation (1). Equation (2) may then be solved for δ and equation (3) for ε. At distances greater than 80/f^1/3 MHz kilometers the curves of Graph 21 do not give the correct relative values of field strength since the curvature of the earth weakens the field more rapidly than these plane earth curves would indicate. Thus, no attempt should be made to fit experimental data to these curves at the larger distances.

Note: For other values of dielectric constant, use can be made of the computer program which was employed by the FCC in generating the curves in Graphs 1 to 20. For information on obtaining a printout of this program, call or write the Consumer Affairs Office, Federal Communications Commission, Washington, DC 200554, (202) 632–7000.

(d) At sufficiently short distances (less than 55 kilometers at AM broadcast frequencies), such that the curvature of the earth does not introduce an additional attenuation of the waves, the curves of Graph 21 may be used to determine the groundwave field strength of transmitting and receiving antennas at the surface of the earth for any radiated power, frequency, or set of ground constants. First, trace the straight inverse distance line corresponding to the power radiated on transparent log-log graph paper similar to that of Graph 21, labelling the ordinates of the chart in terms of field strength, and the abscissae in terms of distance. Next, using the formulas given on Graph 21, calculate the value of the numerical distance, p, at 1 kilometer, and the value of b. Then superimpose the log-log graph paper over Graph 21, shifting it vertically until both inverse distance lines coincide and shifting it horizontally until the numerical distance at 1 kilometer on Graph 21 coincides with 1 kilometer on the log-log graph paper. The curve of Graph 21 corresponding to the calculated value of b is then traced on the log-log graph paper giving the field strength versus distance in kilometers.

(e) This paragraph consists of the following Graphs 1 to 20 and 21.

Note: The referenced graphs are not published in the CFR, nor will they be included in the Commission's automated rules system. For information on obtaining copies of the graphs call or write the Consumer Affairs Office, Federal Communications Commission, Washington, DC 20554, Telephone: (202) 632–7000.

[28 FR 13574, Dec. 14, 1963, as amended at 50 FR 18823, May 2, 1985; 51 FR 45891, Dec. 23, 1986; 52 FR 36878, Oct. 1, 1987; 56 FR 64866, Dec. 12, 1991; 57 FR 43290, Sept. 18, 1992]

(a) Measured values of radiation are not to be used in calculating overlap, interference, and coverage.

(1) In the case of an antenna which is intended to be non-directional in the horizontal plane, an ideal non-directional radiation pattern shall be used in determining interference, overlap, and coverage, even if the antenna is not actually non-directional.

(2) In the case of an antenna which is directional in the horizontal plane, the radiation which shall be used in determining interference, overlap, and coverage is that calculated pursuant to §73.150 or §73.152, depending on whether the station has a standard or modified standard pattern.

(3) In the case of calculation of interference or overlap to (not from) a foreign station, the notified radiation shall be used, even if the notified radiation differs from that in paragraphs (a) (1) or (2) of this section.

(b) For skywave signals from stations operating on all channels, interference shall be determined from the appropriate formulas and Figure 6a contained in §73.190.

(c) The formulas in §73.190(d) depicted in Figure 6a of §73.190, entitled “Angles of Departure versus Transmission Range” are to be used in determining the angles in the vertical pattern of the antenna of an interfering station to be considered as pertinent to transmission by one reflection. To provide for variation in the pertinent vertical angle due to variations of ionosphere height and ionosphere scattering, the curves 2 and 3 indicate the upper and lower angles within which the radiated field is to be considered. The maximum value of field strength occurring between these angles shall be used to determine the multiplying factor to apply to the 10 percent skywave field intensity value determined from Formula 2 in §73.190. The multiplying factor is found by dividing the maximum radiation between the pertinent angles by 100 mV/m.

(d) Example of the use of skywave curves and formulas: Assume a proposed new Class B station from which interference may be expected is located at a distance of 724 kilometers from a licensed Class B station. The proposed station specifies geographic coordinates of 40°00'00" N and 100°00'00" W and the station to be protected is located at an azimuth of 45° true at geographic coordinates of 44°26'05" N and 93°32'54" W. The critical angles of radiation as determined from Figure 6a of §73.190 for use with Class B stations are 9.6° and 16.6°. If the vertical pattern of the antenna of the proposed station in the direction of the existing station is such that, between the angles of 9.6° and 16.6° above the horizon the maximum radiation is 260 mV/m at one kilometer, the value of the 50% field, as derived from Formula 1 of §73.190, is 0.06217 mV/m at the location of the existing station. To obtain the value of the 10% field, the 50% value must be adjusted by a factor derived from Formula 2 of §73.190. The value in this case is 8.42 dB. Thus, the 10% field is 0.1616 mV/m. Using this in conjunction with the co-channel protection ratio of 26 dB, the resultant nighttime limit from the proposed station to the licensed station is 3.232 mV/m.

(e) In the case of an antenna which is non-directional in the horizontal plane, the vertical distribution of the relative fields should be computed pursuant to §73.160. In the case of an antenna which is directional in the horizontal plane, the vertical pattern in the great circle direction toward the point of reception in question must first be calculated. In cases where the radiation in the vertical plane, at the pertinent azimuth, contains a large lobe at a higher angle than the pertinent angle for one reflection, the method of calculating interference will not be restricted to that just described; each such case will be considered on the basis of the best knowledge available.

(f) In performing calculations to determine permissible radiation from stations operating presunrise or postsunset in accordance with §73.99, calculated diurnal factors will be multiplied by the values of skywave field strength for such stations obtained from Formula 1 or 2 of §73.190.

(1) The diurnal factor is determined using the time of day at the mid-point of path between the site of the interfering station and the point at which interference is being calculated. Diurnal factors are computed using the formula D_f=a+bF+cF² +dF³ where:

D_f represents the diurnal factor,

A diurnal factor greater than one will not be used in calculations and interpolation is to be used between calculated values where necessary. For reference purposes, curves for presunrise and postsunset diurnal factors are contained in Figures 13 and 14 of §73.190.

(2) Constants used in calculating diurnal factors for the presunrise and postsunset periods are contained in paragraphs (f)(2) (i) and (ii) of this section respectively. The columns labeled T_mp represent the number of hours before and after sunrise and sunset at the path midpoint.

(i) Presunrise Constants

(ii) Postsunset Constants

Editorial Note:  At 56 FR 64867, Dec. 12, 1991, §73.185 was amended by redesignating paragraphs (d), (e), (h), and (k) as (c), (d), (e), and (f), resulting in two consecutive paragraph (f)'s. These paragraphs will be correctly designated by a Federal Communication Commission document published in the Federal Register at a later date.

(f) For stations operating on regional and local channels, interfering skywave field intensities shall be determined in accordance with the procedure specified in (d) of this section and illustrated in (e) of this section, except that Figure 2 of §73.190 is used in place of Figure 1a and 1b and the formulas of §73.190. In using Figure 2 of §73.190, one additional parameter must be considered, i.e., the variation of received field with the latitude of the path.

(g) Figure 2 of §73.190, “10 percent Skywave Signal Range Chart,” shows the signal as a function of the latitude of the transmission path, which is defined as the geographic latitude of the midpoint between the transmitter and receiver. When using Figure 2 of §73.190, latitude 35° should be used in case the mid-point of the path lies below 35° North and latitude 50° should be used in case the mid-point of the path lies above 50° North.

[30 FR 13783, Oct. 29, 1965, as amended at 33 FR 15420, Oct. 17, 1968; 46 FR 11995, Feb. 12, 1981; 48 FR 42958, Sept. 20, 1983; 50 FR 18843, May 2, 1985; 56 FR 64867, Dec. 12, 1991]

(a) Section 73.189 provides that certain minimum field strengths are acceptable in lieu of the required minimum physical heights of the antennas proper. Also, in other situations, it may be necessary to determine the effective field. The following requirements shall govern the taking and submission of data on the field strength produced:

(1) Beginning as near to the antenna as possible without including the induction field and to provide for the fact that a broadcast antenna is not a point source of radiation (not less than one wave length or 5 times the vertical height in the case of a single element, i.e., nondirectional antenna or 10 times the spacing between the elements of a directional antenna), measurements shall be made on six or more radials, at intervals of approximately 0.2 kilometer up to 3 kilometers from the antenna, at intervals of approximately one kilometer from 3 kilometers to 5 kilometers from the antenna, at intervals of approximately 2 kilometers from 5 kilometers to 15 kilometers from the antenna, and a few additional measurements if needed at greater distances from the antenna. Where the antenna is rurally located and unobstructed measurements can be made, there shall be at least 15 measurements on each radial. These shall include at least 7 measurements within 3 kilometers of the antenna. However, where the antenna is located in a city where unobstructed measurements are difficult to make, measurements shall be made on each radial at as many unobstructed locations as possible, even though the intervals are considerably less than stated above, particularly within 3 kilometers of the antenna. In cases where it is not possible to obtain accurate measurements at the closer distances (even out to 8 or 10 kilometers due to the character of the intervening terrain), the measurements at greater distances should be made at closer intervals.

(2) The data required by paragraph (a)(1) of this section should be plotted for each radial in accordance with either of the two methods set forth below:

(i) Using log-log coordinate paper, plot field strengths as ordinate and distance as abscissa.

(ii) Using semi-log coordinate paper, plot field strength times distance as ordinate on the log scale and distance as abscissa on the linear scale.

(3) However, regardless of which of the methods in paragraph (a)(2) of this section is employed, the proper curve to be drawn through the points plotted shall be determined by comparison with the curves in §73.184 as follows: Place the sheet on which the actual points have been plotted over the appropriate Graph in §73.184, hold to the light if necessary and adjust until the curve most closely matching the points is found. This curve should then be drawn on the sheet on which the points were plotted, together with the inverse distance curve corresponding to that curve. The field at 1 kilometer for the radial concerned shall be the ordinate on the inverse distance curve at 1 kilometer.

(4) When all radials have been analyzed in accordance with paragraph (a)(3) of this section, a curve shall be plotted on polar coordinate paper from the fields obtained, which gives the inverse distance field pattern at 1 kilometer. The radius of a circle, the area of which is equal to the area bounded by this pattern, is the effective field. (See §73.14.)

(5) The antenna power of the station shall be maintained at the authorized level during all field measurements. The power determination will be made using the direct method as described in §73.51(a) with instruments of acceptable accuracy specified in §73.1215.

(b) Complete data taken in conjunction with the field strength measurements shall be submitted to the Commission in affidavit form including the following:

(1) Tabulation by number of each point of measurement to agree with the maps required in paragraph (c) of this section, the date and time of each measurement, the field strength (E), the distance from the antenna (D) and the product of the field strength and distance (ED) (if data for each radial are plotted on semilogarithmic paper, see paragraph (a)(2)(ii) of this section) for each point of measurement.

(2) Description of method used to take field strength measurements.

(3) The family of theoretical curves used in determining the curve for each radial properly identified by conductivity and dielectric constants.

(4) The curves drawn for each radial and the field strength pattern.

(5) The antenna resistance at the operating frequency.

(6) Antenna current or currents maintained during field strength measurements.

(c) Maps showing each measurement point numbered to agree with the required tabulation shall be retained in the station records and shall be available to the FCC upon request.

[28 FR 13574, Dec. 14, 1963, as amended at 41 FR 44178, Oct. 7, 1976; 46 FR 11995, Feb. 12, 1981; 49 FR 49851, Dec. 24, 1984; 50 FR 18843, May 2, 1985; 50 FR 47055, Nov. 14, 1985; 51 FR 2707, Jan. 21, 1986; 52 FR 10570, Apr. 2, 1987; 66 FR 20757, Apr. 25, 2001]

(a)(1) Except as otherwise provided in paragraphs (a)(2) and (3) of this section, no authorization will be granted for a Class B or Class D station on a frequency specified in §73.25 if the proposed operation would radiate during the period of critical hours (the two hours after local sunrise and the two hours before local sunset) toward any point on the 0.1 mV/m contour of a co-channel U.S. Class A station, at or below the pertinent vertical angle determined from Curve 2 of Figure 6a of §73.190, values in excess of those obtained as provided in paragraph (b) of this section.

(2) The limitation set forth in paragraph (a)(1) of this section shall not apply in the following cases:

(i) Any Class B or Class D operation authorized before November 30, 1959; or

(ii) For Class B and Class D stations authorized before November 30, 1959, subsequent changes of facilities which do not involve a change in frequency, an increase in radiation toward any point on the 0.1 mV/m contour of a co-channel U.S. Class A station, or the move of transmitter site materially closer to the 0.1 mV/m contour of such Class A station.

(3) A Class B or Class D station authorized before November 30, 1959, and subsequently authorized to increase daytime radiation in any direction toward the 0.1 mV/m contour of a co-channel U.S. Class A station (without a change in frequency or a move of transmitter site materially closer to such contour), may not, during the two hours after local sunrise or the two hours before local sunset, radiate in such directions a value exceeding the higher of:

(i) The value radiated in such directions with facilities last authorized before November 30, 1959, or

(ii) The limitation specified in paragraph (a)(1) of this section.

(b) To obtain the maximum permissible radiation for a Class B or Class D station on a given frequency from 640 through 990 kHz, multiply the radiation value obtained for the given distance and azimuth from the 500 kHz chart (Figure 9 of §73.190) by the appropriate interpolation factor shown in the K₅₀₀ column of paragraph (c) of this section; and multiply the radiation value obtained for the given distance and azimuth from the 1000 kHz chart (Figure 10 of §73.190) by the appropriate interpolation factor shown in the K₁₀₀₀ column of paragraph (c) of this section. Add the two products thus obtained; the result is the maximum radiation value applicable to the Class B or Class D station in the pertinent directions. For frequencies from 1010 to 1580 kHz, obtain in a similar manner the proper radiation values from the 1000 and 1600 kHz charts (Figures 10 and 11 of §73.190), multiply each of these values by the appropriate interpolation factors in the K'₁₀₀₀ and K'₁₆₀₀ columns in paragraph (c) of this section, and add the products.

(c) Interpolation factors. (1) Frequencies below 1000 kHz.

(2) Frequencies above 1000 kHz.

[28 FR 13574, Dec. 14, 1963, as amended at 49 FR 43962, Nov. 1, 1984; 56 FR 64868, Dec. 12, 1991]

(a) Section 73.45 requires that all applicants for new, additional, or different broadcast facilities and all licensees requesting authority to move 0the transmitter of an existing station, shall specify a radiating system, the efficiency of which complies with the requirements of good engineering practice for the class and power of the station.

(b) The specifications deemed necessary to meet the requirements of good engineering practice at the present state of the art are set out in detail below.

(1) The licensee of a AM broadcast station requesting a change in power, time of operation, frequency, or transmitter location must also request authority to install a new antenna system or to make changes in the existing antenna system which will meet the minimum height requirements, or submit evidence that the present antenna system meets the minimum requirements with respect to field strength, before favorable consideration will be given thereto. (See §73.186.) In the event it is proposed to make substantial changes in an existing antenna system, the changes shall be such as to meet the minimum height requirements or will be permitted subject to the submission of field strength measurements showing that it meets the minimum requirements with respect to effective field strength.

(2) These minimum actual physical vertical heights of antennas permitted to be installed are shown by curves A, B, and C of Figure 7 of §73.190 as follows:

(i) Class C stations, and stations in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands on 1230, 1240, 1340, 1400, 1450 and 1490 kHz that were formerly Class C and were redesignated as Class B pursuant to §73.26(b), 45 meters or a minimum effective field strength of 241 mV/m for 1 kW (121 mV/m for 0.25 kW). (This height applies to a Class C station on a local channel only. Curve A shall apply to any Class C stations in the 48 conterminous States that are assigned to Regional channels.)

(ii) Class A (Alaska), Class B and Class D stations other than those covered in §73.189(b)(2)(i), a minimum effective field strength of 282 mV/m for 1 kW.

(iii) Class A stations, a minimum effective field strength of 362 mV/m for 1 kW.

(3) The heights given on the graph for the antenna apply regardless of whether the antenna is located on the ground or on a building. Except for the reduction of shadows, locating the antenna on a building does not necessarily increase the efficiency and where the height of the building is in the order of a quarter wave the efficiency may be materially reduced.

(4) At the present development of the art, it is considered that where a vertical radiator is employed with its base on the ground, the ground system should consist of buried radial wires at least one-fourth wave length long. There should be as many of these radials evenly spaced as practicable and in no event less than 90. (120 radials of 0.35 to 0.4 of a wave length in length and spaced 3° is considered an excellent ground system and in case of high base voltage, a base screen of suitable dimensions should be employed.)

(5) In case it is contended that the required antenna efficiency can be obtained with an antenna of height or ground system less than the minimum specified, a complete field strength survey must be supplied to the Commission showing that the field strength at a mile without absorption fulfills the minimum requirements. (See §73.186.) This field survey must be made by a qualified engineer using equipment of acceptable accuracy.

(6) The main element or elements of a directional antenna system shall meet the above minimum requirements with respect to height or effective field strength. No directional antenna system will be approved which is so designed that the effective field of the array is less than the minimum prescribed for the class of station concerned, or in case of a Class A station less than 90 percent of the ground wave field which would be obtained from a perfect antenna of the height specified by Figure 7 of §73.190 for operation on frequencies below 1000 kHz, and in the case of a Class B or Class D station less than 90 percent of the ground wave field which would be obtained from a perfect antenna of the height specified by Figure 7 of §73.190 for operation on frequencies below 750 kHz.

[28 FR 13574, Dec. 14, 1963, as amended at 31 FR 8069, June 8, 1966; 33 FR 15420, Oct. 17, 1968; 44 FR 36038, June 20, 1979; 50 FR 18844, May 2, 1985; 51 FR 2707, Jan. 21, 1986; 51 FR 4753, Feb. 7, 1986; 52 FR 10570, Apr. 2, 1987; 56 FR 64868, Dec. 12, 1991]

(a) This section consists of the following Figures: 2, r3, 5, 6a, 7, 8, 9, 10, 11, 12, and 13. Additionally, formulas that are directly related to graphs are included.

(b) Formula 1 is used for calculation of 50% skywave field strength values.

Formula 1. Skywave field strength, 50% of the time (at SS+6):

The skywave field strength, Fc(50), for a characteristic field strength of 100 mV/m at 1 km is given by:

$$

The slant distance, D, is given by:

$$

The geomagnetic latitude of the midpoint of the path, ΦM, is given by:

ΦM =arcsin[sin aM sin 78.5° + cos aM cos 78.5° cos(69 + bM)]degrees                (Eq. 3)

The short great-circle path distance, d, is given by:

$$

Where:

d° = arccos[sin aT sin aR + cos aT cos aR cos(bR − b_T)]degrees                    (Eq.5)

Where:

aT is the geographic latitude of the transmitting terminal (degrees)

aR is the geographic latitude of the receiving terminal (degrees)

bT is the geographic longitude of the transmitting terminal (degrees)

bR is the geographic longitude of the receiving terminal (degrees)

aM is the geographic latitude of the midpoint of the great-circle path (degrees) and is given by:

bM is the geographic longitude of the midpoint of the great-circle path (degrees) and is given by:

$$$$

Note (1): If |FM| is greater than 60 degrees, equation (1) is evaluated for | FM| = 60 degrees.

Note (2): North and east are considered positive; south and west negative.

Note (3): In equation (7), k = −1 for west to east paths (i.e., bR > bT), otherwise k = 1.

(c) Formula 2 is used for calculation of 10% skywave field strength values.

Formula 2. Skywave field strength, 10% of the time (at SS+6):

(d) Figure 6a depicts angles of departure versus transmission range. These angles may also be computed using the following formulas:

Where:

Note: Computations using these formulas should not be carried beyond 0.1 degree.

(e) In the event of disagreement between computed values using the formulas shown above and values obtained directly from the figures, the computed values will control.

[28 FR 13574, Dec. 14, 1963, as amended at 30 FR 12720, Oct. 6, 1965; 33 FR 15420, Oct 17, 1968; 48 FR 42959, Sept. 20, 1983; 49 FR 43963, Nov. 1, 1984; 50 FR 18844, May 2, 1985; 51 FR 4753, Feb. 7, 1986; 52 FR 36879, Oct. 1, 1987; 56 FR 64869, Dec. 12, 1991]

The FM broadcast band consists of that portion of the radio frequency spectrum between 88 MHz and 108 MHz. It is divided into 100 channels of 200 kHz each. For convenience, the frequencies available for FM broadcasting (including those assigned to noncommercial educational broadcasting) are given numerical designations which are shown in the table below:

[28 FR 13623, Dec. 14, 1963, as amended at 30 FR 4480, Apr. 7, 1965; 52 FR 10570, Apr. 2, 1987]

Link to an amendment published at 71 FR 45426, August 9, 2006.

Link to an amendment published at 71 FR 45426, August 9, 2006.

Link to an amendment published at 71 FR 45427, August 9, 2006.

Link to an amendment published at 71 FR 47150, August 16, 2006.

Link to an amendment published at 71 FR 47151, August 16, 2006.

Link to an amendment published at 71 FR 47151, August 16, 2006.

Link to an amendment published at 71 FR 49381, August 23, 2006.

Link to an amendment published at 71 FR 50001, August 24, 2006.

(a) General. The following Table of Allotments contains the channels (other than noncommercial educational Channels 201–220) designated for use in communities in the United States, its territories, and possessions. All listed channels are for Class B stations in Zones I and I-A and for Class C stations in Zone II unless otherwise specifically designated.

(1) Channels designated with an asterisk may be used only by noncommercial educational broadcast stations. The rules governing the use of those channels are contained in part 73, subpart C of this chapter. An entity that would be eligible to operate a noncommercial educational broadcast station can, in conjunction with an initial petition for rulemaking filed pursuant to part 1, subpart C of this chapter, request that a nonreserved FM channel (channels 221 through 300) be allotted as reserved only for noncommercial educational broadcasting by demonstrating the following:

(i) No reserved channel can be used without causing prohibited interference to TV channel 6 stations or foreign broadcast stations; or

(ii) The applicant is technically precluded from using the reserved band by existing stations or previously filed applications and the proposed station would provide a first or second noncommercial educational radio service to 2,000 or more people who constitute 10% of the population within the proposed allocation's 60 dBu (1 mV/m) service contour.

(2) Each channel listed in the Table of Allotments reflects the class of station that is authorized, or has an application filed, to use it based on the minimum and maximum facility requirements for each class contained in §73.211.

Note: The provisions of this paragraph [(a)(2) of this section] become effective [3 years from the effective date of the Report and Order in BC Docket 80–90].

(b) Table of FM Allotments.

(Sec. 316, 66 Stat. 717; 47 U.S.C. 316; sec. 5, 48 Stat., as amended, 1068; 47 U.S.C. 154, 155; secs. 2, 3, 4, 301, 303, 307, 308, 309, 315, 317, 48 Stat. as amended, 1064, 1065, 1066, 1081, 1082, 1083, 1084, 1085, 1088, 1089; (47 U.S.C. 152, 153, 301, 303, 307, 308, 309, 315, 317); secs 1, 201–205, 208, 215, 218, 313, 314, 403, 404, 410, 602; 48 Stat. as amended; 1070, 1071, 1072, 1073, 1076, 1077, 1087, 1094, 1098, 1102 (47 U.S.C. 151, 201–205, 208, 215, 218, 313, 314, 403, 404, 410, 602))

[30 FR 12711, Oct. 6, 1965]

Editorial Note:  For Federal Register citations affecting §73.202 see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO Access.

§ 73.203   Availability of channels.

(a) Except as provided for in paragraph (b) of this section, applications may be filed to construct FM broadcast stations only at the communities and on the channels contained in the Table of Allotments (§73.202(b)). Applications that fail to comply with this requirements, whether or not accompanied by a petition to amend the Table, will not be accepted for tender.

(b) Applications filed on a first come, first served basis may propose a lower or higher class adjacent, intermediate frequency or co-channel. Applications for the modification of an existing FM broadcast station may propose a lower or higher class adjacent, intermediate frequency or co-channel, or a same class adjacent channel. In these cases, the applicant need not file a petition for rule making to amend the Table of Allotments (§73.202(b)) to specify the modified channel class.

Note: Changes in channel and/or class by application are limited to modifications on first, second and third adjacent channels, intermediate frequency (IF) channels, and co-channels which require no other changes to the FM Table of Allotments. Applications requesting such modifications must meet either the minimum spacing requirements of §73.207 at the site specified in the application, without resort to the provisions of the Commission's Rules permitting short spaced stations as set forth in §§73.213 through 73.215 or demonstrate by a separate exhibit attached to the application the existence of a suitable allotment site that fully complies with §§73.207 and 73.315 without resort to §§73.213 through 73.215.

[54 FR 11954, Mar. 23, 1989, as amended at 58 FR 38535, July 19, 1993]

See §§73.207, 73.220 and 73.1650.

[49 FR 10264, Mar. 20, 1984]

For the purpose of allotments and assignments, the United States is divided into three zones as follows:

(a) Zone I consists of that portion of the United States located within the confines of the following lines drawn on the United States Albers Equal Area Projection Map (based on standard parallels 291/2° and 451/2°; North American datum): Beginning at the most easterly point on the State boundary line between North Carolina and Virginia; thence in a straight line to a point on the Virginia-West Virginia boundary line located at north latitude 37°49' and west longitude 80°12'30"; thence westerly along the southern boundary lines of the States of West Virginia, Ohio, Indiana, and Illinois to a point at the junction of the Illinois, Kentucky, and Missouri State boundary lines; thence northerly along the western boundary line of the State of Illinois to a point at the junction of the Illinois, Iowa, and Wisconsin State boundary lines; thence easterly along the northern State boundary line of Illinois to the 90th meridian; thence north along this meridian to the 43.5° parallel; thence east along this parallel to the United States-Canada border; thence southerly and following that border until it again intersects the 43.5° parallel; thence east along this parallel to the 71st meridian; thence in a straight line to the intersection of the 69th meridian and the 45th parallel; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a city, the city shall be considered to be located in Zone I. (See Figure 1 of §73.699.)

(b) Zone I-A consists of Puerto Rico, the Virgin Islands and that portion of the State of California which is located south of the 40th parallel.

(c) Zone II consists of Alaska, Hawaii and the rest of the United States which is not located in either Zone I or Zone I-A.

[29 FR 14116, Oct. 14, 1964, and 31 FR 10125, July 27, 1966, as amended at 48 FR 29504, June 27, 1983]

(a) Except for assignments made pursuant to §73.213 or 73.215, FM allotments and assignments must be separated from other allotments and assignments on the same channel (co-channel) and five pairs of adjacent channels by not less than the minimum distances specified in paragraphs (b) and (c) of this section. The Commission will not accept petitions to amend the Table of Allotments unless the reference points meet all of the minimum distance separation requirements of this section. The Commission will not accept applications for new stations, or applications to change the channel or location of existing assignments unless transmitter sites meet the minimum distance separation requirements of this section, or such applications conform to the requirements of §73.213 or 73.215. However, applications to modify the facilities of stations with short-spaced antenna locations authorized pursuant to prior waivers of the distance separation requirements may be accepted, provided that such applications propose to maintain or improve that particular spacing deficiency. Class D (secondary) assignments are subject only to the distance separation requirements contained in paragraph (b)(3) of this section. (See §73.512 for rules governing the channel and location of Class D (secondary) assignments.)

(b) The distances listed in Tables A, B, and C apply to allotments and assignments on the same channel and each of five pairs of adjacent channels. The five pairs of adjacent channels are the first (200 kHz above and 200 kHz below the channel under consideration), the second (400 kHz above and below), the third (600 kHz above and below), the fifty-third (10.6 MHz above and below), and the fifty-fourth (10.8 MHz above and below). The distances in the Tables apply regardless of whether the proposed station class appears first or second in the “Relation” column of the table.

(1) Domestic allotments and assignments must be separated from each other by not less than the distances in Table A which follows:

(2) Under the Canada-United States FM Broadcasting Agreement, domestic U.S. allotments and assignments within 320 kilometers (199 miles) of the common border must be separated from Canadian allotments and assignments by not less than the distances given in Table B, which follows. When applying Table B, U.S. Class C2 allotments and assignments are considered to be Class B; also, U.S. Class C3 allotments and assignments and U.S. Class A assignments operating with more than 3 kW ERP and 100 meters antenna HAAT (or equivalent lower ERP and higher antenna HAAT based on a class contour distance of 24 km) are considered to be Class B1.

(3) Under the 1992 Mexico-United States FM Broadcasting Agreement, domestic U.S. assignments or allotments within 320 kilometers (199 miles) of the common border must be separated from Mexican assignments or allotments by not less than the distances given in Table C in this paragraph (b)(3). When applying Table C—

(i) U.S. or Mexican assignments or allotments which have been notified internationally as Class A are limited to a maximum of 3.0 kW ERP at 100 meters HAAT, or the equivalent;

(ii) U.S. or Mexican assignments or allotments which have been notified internationally as Class AA are limited to a maximum of 6.0 kW ERP at 100 meters HAAT, or the equivalent;

(iii) U.S. Class C3 assignments or allotments are considered Class B1;

(iv) U.S. Class C2 assignments or allotments are considered Class B; and

(v) Class C1 assignments or allotments assume maximum facilities of 100 kW ERP at 300 meters HAAT. However, U.S. Class C1 stations may not, in any event, exceed the domestic U.S. limit of 100 kW ERP at 299 meters HAAT, or the equivalent.

(c) The distances listed below apply only to allotments and assignments on Channel 253 (98.5 MHz). The Commission will not accept petitions to amend the Table of Allotments, applications for new stations, or applications to change the channel or location of existing assignments where the following minimum distances (between transmitter sites, in kilometers) from any TV Channel 6 allotment or assignment are not met:

[48 FR 29504, June 27, 1983, as amended at 49 FR 10264, Mar. 20, 1984; 49 FR 19670, May 9, 1984; 49 FR 50047, Dec. 26, 1984; 51 FR 26250, July 22, 1986; 54 FR 14963, Apr. 14, 1989; 54 FR 16366, Apr. 24, 1989; 54 FR 19374, May 5, 1989; 54 FR 35338, Aug. 25, 1989; 56 FR 27426, June 14, 1991; 56 FR 57293, Nov. 8, 1991; 62 FR 50256, Sept. 25, 1997; 65 FR 79776, Dec. 20, 2000]

(a)(1) The following reference points must be used to determine distance separation requirements when petitions to amend the Table of Allotments (§73.202(b)) are considered:

(i) First, transmitter sites if authorized, or if proposed in applications with cut-off protection pursuant to paragraph (a)(3) of this section;

(ii) Second, reference coordinates designated by the FCC;

(iii) Third, coordinates listed in the United States Department of Interior publication entitled Index to the National Atlas of the United States of America; or

(iv) Last, coordinates of the main post office.

(The community's reference points for which the petition is submitted will normally be the coordinates listed in the above publication.)

(2) When the distance between communities is calculated using community reference points and it does not meet the minimum separation requirements of §73.207, the channel may still be allotted if a transmitter site is available that would meet the minimum separation requirements and still permit the proposed station to meet the minimum field strength requirements of §73.315. A showing indicating the availability of a suitable site should be sumitted with the petition. In cases where a station is not authorized in a community or communities and the proposed channel cannot meet the separation requirement a showing should also be made indicating adequate distance between suitable transmitter sites for all communities.

(3) Petitions to amend the Table of Allotments that do not meet minimum distance separation requirements to transmitter sites specified in pending applications will not be considered unless they are filed no later than:

(i) The last day of a filing window if the application is for a new FM facility or a major change in the non-reserved band and is filed during a filing window established under section 73.3564(d)(3); or

(ii) The cut-off date established in a Commission Public Notice under §73.3564(d) and 73.3573(e) if the application is for a new FM facility or a major change in the reserved band; or

(iii) The date of receipt of all other types of FM applications. If an application is amended so as to create a conflict with a petition for rule making filed prior to the date the amendment is filed, the amended application will be treated as if filed on the date of the amendment for purposes of this paragraph (a)(3).

Note: If the filing of a conflicting FM application renders an otherwise timely filed counterproposal unacceptable, the counterproposal may be considered in the rulemaking proceeding if it is amended to protect the site of the previously filed FM application within 15 days after being placed on the Public Notice routinely issued by the staff concerning the filing of counterproposals. No proposals involving communities not already included in the proceeding can be introduced during the reply comment period as a method of resolving conflicts. The counterproponent is required to make a showing that, at the time it filed the counterproposal, it did not know, and could not have known by exercising due diligence, of the pendency of the conflicting FM application.

(b) Station separations in licensing proceedings shall be determined by the distance between the coordinates of the proposed transmitter site in one community and

(1) The coordinates of an authorized transmitter site for the pertinent channel in the other community; or, where such transmitter site is not available for use as a reference point,

(2) Reference coordinates designated by the FCC; or, if none are designated,

(3) The coordinates of the other community as listed in the publication listed in paragraph (a) of this section; or, if not contained therein,

(4) The coordinates of the main post office of such other community.

(5) In addition, where there are pending applications in other communities which, if granted, would have to be considered in determining station separations, the coordinates of the transmitter sites proposed in such applications must be used to determine whether the requirements with respect to minimum separations between the proposed stations in the respective cities have been met.

(c) The method given in this paragraph shall be used to compute the distance between two reference points, except that, for computation of distance involving stations in Canada and Mexico, the method for distance computation specified in the applicable international agreement shall be used instead. The method set forth in this paragraph is valid only for distances not exceeding 475 km (295 miles).

(1) Convert the latitudes and longitudes of each reference point from degree-minute-second format to degree-decimal format by dividing minutes by 60 and seconds by 3600, then adding the results to degrees.

(2) Calculate the middle latitude between the two reference points by averaging the two latitudes as follows:

ML=(LAT1_dd+LAT2_dd)÷2

(3) Calculate the number of kilometers per degree latitude difference for the middle latitude calculated in paragraph (c)(2) as follows:

KPD_lat=111.13209−0.56605 cos(2ML)+0.00120 cos(4ML)

(4) Calculate the number of kilometers per degree longitude difference for the middle latitude calculated in paragraph (c)(2) as follows:

KPD_lon=111.41513 cos(ML)−0.09455 cos(3ML)+0.00012 cos(5ML)

(5) Calculate the North-South distance in kilometers as follows:

NS=KPD_lat(LAT1_dd−LAT2_dd)

(6) Calculate the East-West distance in kilometers as follows:

EW=KPD_lon(LON1_dd−LON2_dd)

(7) Calculate the distance between the two reference points by taking the square root of the sum of the squares of the East-West and North-South distances as follows:

DIST=(NS² + EW² )^0.5

(8) Round the distance to the nearest kilometer.

(9) Terms used in this section are defined as follows:

(i) LAT1_dd and LON1_dd=the coordinates of the first reference point in degree-decimal format.

(ii) LAT2_dd and LON2_dd=the coordinates of the second reference point in degree-decimal format.

(iii) ML=the middle latitude in degree-decimal format.

(iv) KPD_lat=the number of kilometers per degree of latitude at a given middle latitude.

(v) KPD_lon=the number of kilometers per degree of longitude at a given middle latitude.

(vi) NS=the North-South distance in kilometers.

(vii) EW=the East-West distance in kilometers.

(viii) DIST=the distance between the two reference points, in kilometers.

[28 FR 13623, Dec. 14, 1963, as amended at 29 FR 14116, Oct. 14, 1964; 48 FR 29505, June 27, 1983; 52 FR 37788, Oct. 9, 1987; 52 FR 39920, Oct. 26, 1987; 54 FR 9806, Mar. 8, 1989; 57 FR 36020, Aug. 12, 1992; 58 FR 38537, July 19, 1993]

(a) Permittees and licensees of FM broadcast stations are not protected from any interference which may be caused by the grant of a new station, or of authority to modify the facilities of an existing station, in accordance with the provisions of this subpart. However, they are protected from interference caused by Class D (secondary) noncommercial educational FM stations. See §73.509.

(b) The nature and extent of the protection from interference afforded FM broadcast stations operating on Channels 221–300 is limited to that which results when assignments are made in accordance with the rules in this subpart.

(c) Permittees and licensees of FM stations are not protected from interference which may be caused by the grant of a new LPFM station or of authority to modify an existing LPFM station, except as provided in subpart G of this part.

[43 FR 39715, Sept. 6, 1978 and 48 FR 29505, June 27, 1983; 54 FR 9802, Mar. 8, 1989; 65 FR 7640, Feb. 15, 2000; 65 FR 67299, Nov. 9, 2000]

(a) The rules applicable to a particular station, including minimum and maximum facilities requirements, are determined by its class. Possible class designations depend upon the zone in which the station's transmitter is located, or proposed to be located. The zones are defined in §73.205. Allotted station classes are indicated in the Table of Allotments, §73.202. Class A, B1 and B stations may be authorized in Zones I and I-A. Class A, C3, C2, C1, C0 and C stations may be authorized in Zone II.

(b) The power and antenna height requirements for each class are set forth in §73.211. If a station has an ERP and an antenna HAAT such that it cannot be classified using the maximum limits and minimum requirements in §73.211, its class shall be determined using the following procedure:

(1) Determine the reference distance of the station using the procedure in paragraph (b)(1)(i) of §73.211. If this distance is less than or equal to 28 km, the station is Class A; otherwise,

(2) For a station in Zone I or Zone I-A, except for Puerto Rico and the Virgin Islands:

(i) If this distance is greater than 28 km and less than or equal to 39 km, the station is Class B1.

(ii) If this distance is greater than 39 km and less than or equal to 52 km, the station is Class B.

(3) For a station in Zone II:

(i) If this distance is greater than 28 km and less than or equal to 39 km, the station is Class C3.

(ii) If this distance is greater than 39 km and less than or equal to 52 km, the station is Class C2.

(iii) If this distance is greater than 52 km and less than or equal to 72 km, the station is Class C1.

(iv) If this distance is greater than 72 km and less than or equal to 83 km, the station is Class C0.

(v) If this distance is greater than 83 km and less than or equal to 92 km, the station is Class C.

(4) For a station in Puerto Rico or the Virgin Islands:

(i) If this distance is less than or equal to 42 km, the station is Class A.

(ii) If this distance is greater than 42 km and less than or equal to 46 km, the station is Class B1.

(iii) If this distance is greater then 46 km and less than or equal to 78 km, the station is Class B.

[52 FR 37788, Oct. 9, 1987; 52 FR 39920, Oct. 26, 1987, as amended at 54 FR 16367, Apr. 24, 1989; 54 FR 19374, May 5, 1989; 54 FR 35339, Aug. 25, 1989; 65 FR 79777, Dec. 20, 2000]

(a) Minimum requirements. (1) Except as provided in paragraphs (a)(3) and (b)(2) of this section, FM stations must operate with a minimum effective radiated power (ERP) as follows:

(i) The minimum ERP for Class A stations is 0.1 kW.

(ii) The ERP for Class B1 stations must exceed 6 kW.

(iii) The ERP for Class B stations must exceed 25 kW.

(iv) The ERP for Class C3 stations must exceed 6 kW.

(v) The ERP for Class C2 stations must exceed 25 kW.

(vi) The ERP for Class C1 stations must exceed 50 kW.

(vii) The minimum ERP for Class C and C0 stations is 100 kW.

(2) Class C0 stations must have an antenna height above average terrain (HAAT) of at least 300 meters (984 feet). Class C stations must have an antenna height above average terrain (HAAT) of at least 451 meters (1480 feet).

(3) Stations of any class except Class A may have an ERP less than that specified in paragraph (a)(1) of this section, provided that the reference distance, determined in accordance with paragraph (b)(1)(i) of this section, exceeds the distance to the class contour for the next lower class. Class A stations may have an ERP less than 100 watts provided that the reference distance, determined in accordance with paragraph (b)(1)(i) of this section, equals or exceeds 6 kilometers.

(b) Maximum limits. (1) Except for stations located in Puerto Rico or the Virgin Islands, the maximum ERP in any direction, reference HAAT, and distance to the class contour for each FM station class are listed below:

(i) The reference distance of a station is obtained by finding the predicted distance to the 1mV/m contour using Figure 1 of §73.333 and then rounding to the nearest kilometer. Antenna HAAT is determined using the procedure in §73.313. If the HAAT so determined is less than 30 meters (100 feet), a HAAT of 30 meters must be used when finding the predicted distance to the 1 mV/m contour.

(ii) If a station's ERP is equal to the maximum for its class, its antenna HAAT must not exceed the reference HAAT, regardless of the reference distance. For example, a Class A station operating with 6 kW ERP may have an antenna HAAT of 100 meters, but not 101 meters, even though the reference distance is 28 km in both cases.

(iii) Except as provided in paragraph (b)(3) of this section, no station will be authorized in Zone I or I-A with an ERP equal to 50 kW and a HAAT exceeding 150 meters. No station will be authorized in Zone II with an ERP equal to 100 kW and a HAAT exceeding 600 meters.

(2) If a station has an antenna HAAT greater than the reference HAAT for its class, its ERP must be lower than the class maximum such that the reference distance does not exceed the class contour distance. If the antenna HAAT is so great that the station's ERP must be lower than the minimum ERP for its class (specified in paragraphs (a)(1) and (a)(3) of this section), that lower ERP will become the minimum for that station.

(3) For stations located in Puerto Rico or the Virgin Islands, the maximum ERP in any direction, reference HAAT, and distance to the class contour for each FM station class are listed below:

(c) Existing stations. Stations authorized prior to March 1, 1984 that do not conform to the requirements of this section may continue to operate as authorized. Stations operating with facilities in excess of those specified in paragraph (b) of this section may not increase their effective radiated powers or extend their 1 mV/m field strength contour beyond the location permitted by their present authorizations. The provisions of this section will not apply to applications to increase facilities for those stations operating with less than the minimum power specified in paragraph (a) of this section.

(d) Existing Class C stations below minimum antenna HAAT. Class C stations authorized prior to January 19, 2001 that do not meet the minimum antenna HAAT specified in paragraph (a)(2) of this section for Class C stations may continue to operate as authorized subject to the reclassification procedures set forth in Note 4 to §73.3573.

[53 FR 17042, May 13, 1988, as amended at 54 FR 16367, Apr. 24, 1989; 54 FR 19374, May 5, 1989; 54 FR 35339, Aug. 25, 1989; 65 FR 79777, Dec. 20, 2000]

(a) In the issuance of FM broadcast station authorizations, the Commission will specify the transmitter output power and effective radiated power in accordance with the following tabulation:

(b) Antenna heights above average terrain will be rounded out to the nearest meter.

[28 FR 13623, Dec. 14, 1963, as amended at 48 FR 29506, June 27, 1983]

(a) Stations at locations authorized prior to November 16, 1964, that did not meet the separation distances required by §73.207 and have remained continuously short-spaced since that time may be modified or relocated with respect to such short-spaced stations, provided that (i) any area predicted to receive interference lies completely within any area currently predicted to receive co-channel or first-adjacent channel interference as calculated in accordance with paragraph (a)(1) of this section, or that (ii) a showing is provided pursuant to paragraph (a)(2) of this section that demonstrates that the public interest would be served by the proposed changes.

(1) The F(50,50) curves in Figure 1 of §73.333 are to be used in conjunction with the proposed effective radiated power and antenna height above average terrain, as calculated pursuant to §73.313(c), (d)(2) and (d)(3), using data for as many radials as necessary, to determine the location of the desired (service) field strength. The F(50,10) curves in Figure 1a of §73.333 are to be used in conjunction with the proposed effective radiated power and antenna height above average terrain, as calculated pursuant to §73.313(c), (d)(2) and (d)(3), using data for as many radials as necessary, to determine the location of the undesired (interfering) field strength. Predicted interference is defined to exist only for locations where the desired (service) field strength exceeds 0.5 mV/m (54 dBu) for a Class B station, 0.7 mV/m (57 dBu) for a Class B1 station, and 1 mV/m (60 dBu) for any other class of station.

(i) Co-channel interference is predicted to exist, for the purpose of this section, at all locations where the undesired (interfering station) F(50,10) field strength exceeds a value 20 dB below the desired (service) F(50,50) field strength of the station being considered (e.g., where the protected field strength is 60 dBu, the interfering field strength must be 40 dBu or more for predicted interference to exist).

(ii) First-adjacent channel interference is predicted to exist, for the purpose of this section, at all locations where the undesired (interfering station) F(50,10) field strength exceeds a value 6 dB below the desired (service) F(50,50) field strength of the station being considered (e.g., where the protected field strength is 60 dBu, the interfering field strength must be 54 dBu or more for predicted interference to exist).

(2) For co-channel and first-adjacent channel stations, a showing that the public interest would be served by the changes proposed in an application must include exhibits demonstrating that the total area and population subject to co-channel or first-adjacent channel interference, caused and received, would be maintained or decreased. In addition, the showing must include exhibits demonstrating that the area and the population subject to co-channel or first-adjacent channel interference caused by the proposed facility to each short-spaced station individually is not increased. In all cases, the applicant must also show that any area predicted to lose service as a result of new co-channel or first-adjacent-channel interference has adequate aural service remaining. For the purpose of this section, adequate service is defined as 5 or more aural services (AM or FM).

(3) For co-channel and first-adjacent-channel stations, a copy of any application proposing interference caused in any areas where interference is not currently caused must be served upon the licensee(s) of the affected short-spaced station(s).

(4) For stations covered by this paragraph (a), there are no distance separation or interference protection requirements with respect to second-adjacent and third-adjacent channel short-spacings that have existed continuously since November 16, 1964.

(b) Stations at locations authorized prior to May 17, 1989, that did not meet the IF separation distances required by §73.207 and have remained short-spaced since that time may be modified or relocated provided that the overlap area of the two stations' 36 mV/m field strength contours is not increased.

(c) Short spacings involving at least one Class A allotment or authorization. Stations that became short spaced on or after November 16, 1964 (including stations that do not meet the minimum distance separation requirements of paragraph (c)(1) of this section and that propose to maintain or increase their existing distance separations) may be modified or relocated in accordance with paragraph (c)(1) or (c)(2) of this section, except that this provision does not apply to stations that became short spaced by grant of applications filed after October 1, 1989, or filed pursuant to §73.215. If the reference coordinates of an allotment are short spaced to an authorized facility or another allotment (as a result of the revision of §73.207 in the Second Report and Order in MM Docket No. 88–375), an application for the allotment may be authorized, and subsequently modified after grant, in accordance with paragraph (c)(1) or (c)(2) of this section only with respect to such short spacing. No other stations will be authorized pursuant to these paragraphs.

(1) Applications for authorization under requirements equivalent to those of prior rules. Each application for authority to operate a Class A station with no more than 3000 watts ERP and 100 meters antenna HAAT (or equivalent lower ERP and higher antenna HAAT based on a class contour distance of 24 km) must specify a transmitter site that meets the minimum distance separation requirements in this paragraph. Each application for authority to operate a Class A station with more than 3000 watts ERP (up to a maximum of 5800 watts), but with an antenna HAAT lower than 100 meters such that the distance to the predicted 0.05 mV/m (34 dBµV/m) F(50,10) field strength contour does not exceed 98 km must specify a transmitter site that meets the minimum distance separation requirements in this paragraph. Each application for authority to operate an FM station of any class other than Class A must specify a transmitter site that meets the minimum distance separation requirements in this paragraph with respect to Class A stations operating pursuant to this paragraph or paragraph (c)(2) of this section, and that meets the minimum distance separation requirements of §73.207 with respect to all other stations.

(2) Applications for authorization of Class A facilities greater than 3,000 watts ERP and 100 meters HAAT. Each application to operate a Class A station with an ERP and HAAT such that the reference distance would exceed 24 kilometers must contain an exhibit demonstrating the consent of the licensee of each co-channel, first, second or third adjacent channel station (for which the requirements of §73.207 are not met) to a grant of that application. Each such application must specify a transmitter site that meets the applicable IF-related channel distance separation requirements of §73.207. Applications that specify a new transmitter site which is short-spaced to an FM station other than another Class A station which is seeking a mutual increase in facilities may be granted only if no alternative fully-spaced site or less short-spaced site is available. Licensees of Class A stations seeking mutual increases in facilities need not show that a fully spaced site or less short-spaced site is available. Applications submitted pursuant to the provisions of this paragraph may be granted only if such action is consistent with the public interest.

[52 FR 37789, Oct. 9, 1987, as amended at 54 FR 14964, Apr. 14, 1989; 54 FR 35339, Aug. 25, 1989; 56 FR 27426, June 14, 1991; 62 FR 50521, Sept. 26, 1997; 63 FR 33876, June 22, 1998]

The Commission will accept applications that specify short-spaced antenna locations (locations that do not meet the domestic co-channel and adjacent channel minimum distance separation requirements of §73.207); Provided That, such applications propose contour protection, as defined in paragraph (a) of this section, with all short-spaced assignments, applications and allotments, and meet the other applicable requirements of this section. Each application to be processed pursuant to this section must specifically request such processing on its face, and must include the necessary exhibit to demonstrate that the requisite contour protection will be provided. Such applications may be granted when the Commission determines that such action would serve the public interest, convenience, and necessity.

(a) Contour protection. Contour protection, for the purpose of this section, means that on the same channel and on the first, second and third adjacent channels, the predicted interfering contours of the proposed station do not overlap the predicted protected contours of other short-spaced assignments, applications and allotments, and the predicted interfering contours of other short-spaced assignments, applications and allotments do not overlap the predicted protected contour of the proposed station.

(1) The protected contours, for the purpose of this section, are defined as follows. For all Class B and B1 stations on Channels 221 through 300 inclusive, the F(50,50) field strengths along the protected contours are 0.5 mV/m (54 dBµ) and 0.7 mV/m (57 dBµ), respectively. For all other stations, the F(50,50) field strength along the protected contour is 1.0 mV/m (60 dBµ).

(2) The interfering contours, for the purpose of this section, are defined as follows. For co-channel stations, the F(50,10) field strength along the interfering contour is 20 dB lower than the F(50,50) field strength along the protected contour for which overlap is prohibited. For first adjacent channel stations (±200 kHz), the F(50,10) field strength along the interfering contour is 6 dB lower than the F(50,50) field strength along the protected contour for which overlap is prohibited. For both second and third adjacent channel stations (±400 kHz and ±600 kHz), the F(50,10) field strength along the interfering contour is 40 dB higher than the F(50,50) field strength along the protected contour for which overlap is prohibited.

(3) The locations of the protected and interfering contours of the proposed station and the other short-spaced assignments, applications and allotments must be determined in accordance with the procedures of paragraphs (c), (d)(2) and (d)(3) of §73.313, using data for as many radials as necessary to accurately locate the contours.

(4) Protected and interfering contours (in dBu) for stations in Puerto Rico and the U.S. Virgin Islands are as follows:

(b) Applicants requesting short-spaced assignments pursuant to this section must take into account the following factors in demonstrating that contour protection is achieved:

(1) The ERP and antenna HAAT of the proposed station in the direction of the contours of other short-spaced assignments, applications and allotments. If a directional antenna is proposed, the pattern of that antenna must be used to calculate the ERP in particular directions. See §73.316 for additional requirements for directional antennas.

(2) The ERP and antenna HAAT of other short-spaced assignments, applications and allotments in the direction of the contours of the proposed station. The ERP and antenna HAATs in the directions of concern must be determined as follows:

(i) For vacant allotments, contours are based on the presumed use, at the allotment's reference point, of the maximum ERP that could be authorized for the station class of the allotment, and antenna HAATs in the directions of concern that would result from a non-directional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the station class of the allotment.

(ii) For existing stations that were not authorized pursuant to this section, including stations with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, and for applications not requesting authorization pursuant to this section, contours are based on the presumed use of the maximum ERP for the applicable station class (as specified in §73.211), and the antenna HAATs in the directions of concern that would result from a non-directional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the applicable station class, without regard to any other restrictions that may apply (e.g. zoning laws, FAA constraints, application of §73.213).

(iii) For stations authorized pursuant to this section, except stations with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, contours are based on the use of the authorized ERP in the directions of concern, and HAATs in the directions of concern derived from the authorized standard eight-radial antenna HAAT. For stations with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, authorized under this section, contours are based on the presumed use of the maximum ERP for the applicable station class (as specified in §73.211), and antenna HAATs in the directions of concern that would result from a non-directional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the applicable station class, without regard to any other restrictions that may apply.

(iv) For applications containing a request for authorization pursuant to this section, except for applications to continue operation with authorized ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed, contours are based on the use of the proposed ERP in the directions of concern, and antenna HAATs in the directions of concern derived from the proposed standard eight-radial antenna HAAT. For applications to continue operation with an ERP that exceeds the maximum ERP permitted by §73.211 for the standard eight-radial HAAT employed, if processing is requested under this section, contours are based on the presumed use of the maximum ERP for the applicable station class (as specified in §73.211), and antenna HAATs in the directions of concern that would result from a nondirectional antenna mounted at a standard eight-radial antenna HAAT equal to the reference HAAT for the applicable station class, without regard to any other restrictions that may apply.

Note to paragraph (b): Applicants are cautioned that the antenna HAAT in any particular direction of concern will not usually be the same as the standard eight-radial antenna HAAT or the reference HAAT for the station class.

(c) Applications submitted for processing pursuant to this section are not required to propose contour protection of any assignment, application or allotment for which the minimum distance separation requirements of §73.207 are met, and may, in the directions of those assignments, applications and allotments, employ the maximum ERP permitted by §73.211 for the standard eight-radial antenna HAAT employed.

(d) Stations authorized pursuant to this section may be subsequently authorized on the basis of compliance with the domestic minimum separation distance requirements of §73.207, upon filing of an FCC Form 301 or FCC Form 340 (as appropriate) requesting a modification of authorization.

(e) The Commission will not accept applications that specify a short-spaced antenna location for which the following minimum distance separation requirements, in kilometers (miles), are not met:

[54 FR 9802, Mar. 8, 1989, as amended at 54 FR 35340, Aug. 25, 1989; 56 FR 57294, Nov. 8, 1991; 57 FR 46325, Oct. 8, 1992; 65 FR 79777, Dec. 20, 2000; 66 FR 8149, Jan. 29, 2001]

(a) The frequency 89.1 MHz (channel 206) is revised in the New York City metropolitan area for the use of the United Nations with the equivalent of an antenna height of 150 meters (492 feet) above average terrain and effective radiated power of 20 kWs, and the FCC will make no assignments which would cause objectionable interference with such use.

(b) [Reserved]

[43 FR 45845, Oct. 4, 1978, as amended at 46 FR 50376, Oct. 13, 1981, 47 FR 30068, July 12, 1982; 48 FR 29507, June 27, 1983; 70 FR 46676, Aug. 10, 2005]

No licensee of an FM broadcast station shall have any arrangement with a network organization which prevents or hinders another station serving substantially the same area from broadcasting the network's programs not taken by the former station, or which prevents or hinders another station serving a substantially different area from broadcasting any program of the network organization: Provided, however, That this section does not prohibit arrangements under which the station is granted first call within its primary service area upon the network's programs. The term “network organization” means any organization originating program material, with or without commercial messages, and furnishing the same to stations interconnected so as to permit simultaneous broadcast by all or some of them. However, arrangements involving only stations under common ownership, or only the rebroadcast by one station of programming from another with no compensation other than a lump-sum payment by the station rebroadcasting, are not considered arrangements with a network organization. The term “arrangement“ means any contract, arrangement or understanding, express or implied.

[42 FR 16422, Mar. 28, 1977, as amended at 57 FR 48333, Oct. 23, 1992]

No FM broadcast station license or renewal of FM broadcast station license will be granted to any person who owns, leases, or controls a particular site which is peculiarly suitable for FM broadcasting in a particular area and (a) which is not available for use by other FM broadcast station licensees; and (b) no other comparable site is available in the area; and (c) where the exclusive use of such site by the applicant or licensee would unduly limit the number of FM broadcast stations that can be authorized in a particular area or would unduly restrict competition among FM broadcast stations.

[28 FR 13623, Dec. 14, 1963]

(a) Each FM broadcast station shall be equipped with indicating instruments which conform with the specifications described in §73.1215 for determining power by the indirect method; for indicating the relative amplitude of the transmission line radio frequency current, voltage, or power; and with such other instruments as are necessary for the proper adjustment, operation, and maintenance of the transmitting system.

(b) The function of each instrument shall be clearly and permanently shown in the instrument itself or on the panel immediately adjacent thereto.

(c) In the event that any one of these indicating instruments becomes defective when no substitute which conforms with the required specifications is available, the station may be operated without the defective instrument pending its repair or replacement for a period not in excess of 60 days without further authority of the FCC: Provided that, if the defective instrument is the transmission line meter of a station which determines the output power by the direct method, the operating power shall be determined by the indirect method in accordance with §73.267(c) during the entire time the station is operated without the transmission line meter.

(d) If conditions beyond the control of the licensee prevent the restoration of the meter to service within the above allowed period, an informal letter request in accordance with §73.3549 may be filed with the FCC, Attention: Audio Division, Media Bureau, in Washington, DC for such additional time as may be required to complete repairs of the defective instrument.

[41 FR 36818, Sept. 1, 1976, as amended at 48 FR 44805, Sept. 30, 1983; 50 FR 32416, Aug. 12, 1985; 63 FR 33876, June 22, 1998; 67 FR 13231, Mar. 21, 2002]

(a) The operating power of each FM station is to be determined by either the direct or indirect method.

(b) Direct method. The direct method of power determination for an FM station uses the indications of a calibrated transmission line meter (responsive to relative voltage, current, or power) located at the RF output terminals of the transmitter. This meter must be calibrated whenever there is any indication that the calibration is inaccurate or whenever any component of the metering circuit is repaired or replaced. The calibration must cover, as a minimum, the range from 90% to 105% of authorized power. The meter calibration may be checked by measuring the power at the transmitter terminals while either:

(1) Operating the transmitter into the transmitting antenna, and determining actual operating power by the indirect method described in §73.267(c); or

(2) Operating the transmitter into a load (of substantially zero reactance and a resistance equal to the transmission line characteristic impedance) and using an electrical device (within ±5% accuracy) or temperature and coolant flow indicator (within ±4% accuracy) to determine the power.

(3) The calibration must cover, as a minimum, the range from 90% to 105% of authorized power and the meter must provide clear indications which will permit maintaining the operating power within the prescribed tolerance or the meter shall be calibrated to read directly in power units.

(c) Indirect method. The operating power is determined by the indirect method by applying an appropriate factor to the input power to the last radio-frequency power amplifier stage of the transmitter, using the following formula:

Transmitter output power=Ep × Ip × F

Where:

(1) If the above formula is not appropriate for the design of the transmitter final amplifier, use a formula specified by the transmitter manufacturer with other appropriate operating parameters.

(2) The value of the efficiency factor, F, established for the authorized transmitter output power is to be used for maintaining the operating power, even though there may be some variation in F over the power operating range of the transmitter.

(3) The value of F is to be determined and a record kept thereof by one of the following procedures listed in order of preference:

(i) Using the most recent measurement data for calibration of the transmission line meter according to the procedures described in paragraph (b) of this section or the most recent measurements made by the licensee establishing the value of F. In the case of composite transmitters or those in which the final amplifier stages have been modified pursuant to FCC approval, the licensee must furnish the FCC and also retain with the station records the measurement data used as a basis for determining the value of F.

(ii) Using measurement data shown on the transmitter manufacturer's test data supplied to the licensee; Provided, That measurements were made at the authorized frequency and transmitter output power.

(iii) Using the transmitter manufacturer's measurement data submitted to the FCC for type acceptance and as shown in the instruction book supplied to the licensee.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[44 FR 58731, Oct. 11, 1979, as amended at 45 FR 28141, Apr. 28, 1980; 48 FR 38479, Aug. 24, 1983; 49 FR 4210, Feb. 3, 1984; 49 FR 49851, Dec. 24, 1984]

(a) No FM broadcast licensee or permittee shall enter into any agreement, arrangement or understanding, oral or written, whereby it undertakes to supply, or receives consideration for supplying, on its main channel a functional music, background music, or other subscription service (including storecasting) for reception in the place or places of business of any subscriber.

(b) The transmission (or interruption) of radio energy in the FM broadcast band is permissible only pursuant to a station license, program test authority, construction permit, or experimental authorization and the provisions of this part of the rules.

[29 FR 7471, June 10, 1964. Redesignated at 39 FR 38655, Nov. 1, 1974 and amended at 48 FR 28454, June 22, 1983]

Licensees of FM broadcast stations may transmit, without further authorization, subcarrier communication services in accordance with the provisions of §§73.319 and 73.322.

[51 FR 17028, May 8, 1986]

(a) Subsidiary communication services are those transmitted on a subcarrier within the FM baseband signal, but do not include services which enhance the main program broadcast service, or exclusively relate to station operations (see §73.293). Subsidiary communications include, but are not limited to services such as functional music, specialized foreign language programs, radio reading services, utility load management, market and financial data and news, paging and calling, traffic control signal switching, bilingual television audio, and point to point or multipoint messages.

(b) FM subsidiary communications services that are common carrier in nature are subject to common carrier regulation. Licensees operating such services are required to apply to the FCC for the appropriate authorization and to comply with all policies and rules applicable to the service. Responsibility for making the initial determinations of whether a particular activity is common carriage rests with the FM station licensee. Initial determinations by licensees are subject to FCC examination and may be reviewed at the FCC's discretion.

(c) Subsidiary communications services are of a secondary nature under the authority of the FM station authorization, and the authority to provide such communications services may not be retained or transferred in any manner separate from the station's authorization. The grant or renewal of an FM station permit or license is not furthered or promoted by proposed or past services. The permittee or licensee must establish that the broadcast operation is in the public interest wholly apart from the subsidiary communications services provided.

(d) The station identification, delayed recording and sponsor identification announcements required by §§73.1201, 73.1208, and 73.1212 are not applicable to material transmitted under an SCA.

(e) The licensee or permittee must retain control over all material transmitted in a broadcast mode via the station's facilities, with the right to reject any material that it deems inappropriate or undesirable.

[48 FR 28454, June 22, 1983, as amended at 48 FR 44805, Sept. 30, 1983; 49 FR 33663, Aug. 15, 1984; 50 FR 32416, Aug. 12, 1985; 57 FR 48333, Oct. 23, 1992]

(a) An FM broadcast station may, without specific authority from the FCC, transmit stereophonic (biphonic, quadraphonic, etc.) sound programs upon installation of stereophonic sound transmitting equipment under the provisions of §§2.1001, 73.322, and 73.1590 of the Rules. Prior to commencement of stereophonic sound broadcasting, equipment performance measurements must be made to ensure that the transmitted signal complies with all applicable rules and standards.

(b) Each licensee or permittee engaging in multichannel broadcasting must measure the pilot subcarrier frequency as often as necessary to ensure that it is kept at all times within 2 Hz of the authorized frequency.

[48 FR 28454, June 22, 1983, and 48 FR 38479, Aug. 24, 1983]

(a) Frequency modulation.

Antenna height above average terrain (HAAT). HAAT is calculated by: determining the average of the antenna heights above the terrain from 3 to 16 kilometers (2 to 10 miles) from the antenna for the eight directions evenly spaced for each 45° of azimuth starting with True North (a different antenna height will be determined in each direction from the antenna): and computing the average of these separate heights. In some cases less than eight directions may be used. (See §73.313(d).) Where circular or elliptical polarization is used, the antenna height above average terrain must be based upon the height of the radiation of the antenna that transmits the horizontal component of radiation.

Antenna power gain. The square of the ratio of the root-mean-square (RMS) free space field strength produced at 1 kilometer in the horizontal plane in millivolts per meter for 1 kW antenna input power to 221.4 mV/m. This ratio is expressed in decibels (dB). If specified for a particular direction, antenna power gain is based on that field strength in the direction only.

Auxiliary facility. An auxiliary facility is an antenna separate from the main facility's antenna, permanently installed on the same tower or at a different location, from which a station may broadcast for short periods without prior Commission authorization or notice to the Commission while the main facility is not in operation (e.g., where tower work necessitates turning off the main antenna or where lightning has caused damage to the main antenna or transmission system) (See §73.1675).

Center frequency. The term “center frequency” means:

(1) The average frequency of the emitted wave when modulated by a sinusoidal signal.

(2) The frequency of the emitted wave without modulation.

Composite antenna pattern. The composite antenna pattern is a relative field horizontal plane pattern for 360 degrees of azimuth, for which the value at a particular azimuth is the greater of the horizontally polarized or vertically polarized component relative field values. The composite antenna pattern is normalized to a maximum of unity (1.000) relative field.

Composite baseband signal. A signal which is composed of all program and other communications signals that frequency modulates the FM carrier.

Effective radiated power. The term “effective radiated power” means the product of the antenna power (transmitter output power less transmission line loss) times: (1) The antenna power gain, or (2) the antenna field gain squared. Where circular or elliptical polarization is employed, the term effective radiated power is applied separately to the horizontal and vertical components of radiation. For allocation purposes, the effective radiated power authorized is the horizontally polarized component of radiation only.

Equivalent isotropically radiated power (EIRP). The term “equivalent isotropically radiated power (also known as “effective radiated power above isotropic) means the product of the antenna input power and the antenna gain in a given direction relative to an isotropic antenna.

FM Blanketing. Blanketing is that form of interference to the reception of other broadcast stations which is caused by the presence of an FM broadcast signal of 115 dBu (562 mV/m) or greater signal strength in the area adjacent to the antenna of the transmitting station. The 115 dBu contour is referred to as the blanketing contour and the area within this contour is referred to as the blanketing area.

FM broadcast band. The band of frequencies extending from 88 to 108 MHz, which includes those assigned to noncommercial educational broadcasting.

FM broadcast channel. A band of frequencies 200 kHz wide and designated by its center frequency. Channels for FM broadcast stations begin at 88.1 MHz and continue in successive steps of 200 kHz to and including 107.9 MHz.

FM broadcast station. A station employing frequency modulation in the FM broadcast band and licensed primarily for the transmission of radiotelephone emissions intended to be received by the general public.

Field strength. The electric field strength in the horizontal plane.

Free space field strength. The field strength that would exist at a point in the absence of waves reflected from the earth or other reflecting objects.

Frequency departure. The amount of variation of a carrier frequency or center frequency from its assigned value.

Frequency deviation. The peak difference between modulated wave and the carrier frequency.

Frequency modulation. A system of modulation where the instantaneous radio frequency varies in proportion to the instantaneous amplitude of the modulating signal (amplitude of modulating signal to be measured after pre-emphasis, if used) and the instantaneous radio frequency is independent of the frequency of the modulating signal.

Frequency swing. The peak difference between the maximum and the minimum values of the instantaneous frequency of the carrier wave during modulation.

Multiplex transmission. The term “multiplex transmission” means the simultaneous transmission of two or more signals within a single channel. Multiplex transmission as applied to FM broadcast stations means the transmission of facsimile or other signals in addition to the regular broadcast signals.

Percentage modulation. The ratio of the actual frequency deviation to the frequency deviation defined as 100% modulation, expressed in percentage. For FM broadcast stations, a frequency deviation of ±75kHz is defined as 100% modulation.

(b) Stereophonic sound broadcasting.

Cross-talk. An undesired signal occurring in one channel caused by an electrical signal in another channel.

FM stereophonic broadcast. The transmission of a stereophonic program by a single FM broadcast station utilizing the main channel and a stereophonic subchannel.

Left (or right) signal. The electrical output of a microphone or combination of microphones placed so as to convey the intensity, time, and location of sounds originating predominately to the listener's left (or right) of the center of the performing area.

Left (or right) stereophonic channel. The left (or right) signal as electrically reproduced in reception of FM stereophonic broadcasts.

Main channel. The band of frequencies from 50 to 15,000 Hz which frequency-modulate the main carrier.

Pilot subcarrier. A subcarrier that serves as a control signal for use in the reception of FM stereophonic sound broadcasts.

Stereophonic separation. The ratio of the electrical signal caused in sound channel A to the signal caused in sound channel B by the transmission of only a channel B signal. Channels A and B may be any two channels of a stereophonic sound broadcast transmission system.

Stereophonic sound. The audio information carried by plurality of channels arranged to afford the listener a sense of the spatial distribution of sound sources. Stereophonic sound broadcasting includes, but is not limited to, biphonic (two channel), triphonic (three channel) and quadrophonic (four channel) program services.

Stereophonic sound subcarrier. A subcarrier within the FM broadcast baseband used for transmitting signals for stereophonic sound reception of the main broadcast program service.

Stereophonic sound subchannel. The band of frequencies from 23 kHz to 99 kHz containing sound subcarriers and their associated sidebands.

(c) Visual transmissions. Communications or message transmitted on a subcarrier intended for reception and visual presentation on a viewing screen, teleprinter, facsimile printer, or other form of graphic display or record.

(d) Control and telemetry transmissions. Signals transmitted on a multiplex subcarrier intended for any form of control and switching functions or for equipment status data and aural or visual alarms.

[28 FR 13623, Dec. 14, 1963, as amended at 39 FR 10575, Mar. 21, 1974; 44 FR 36038, June 20, 1979; 48 FR 28454, June 22, 1983; 48 FR 29507, June 27, 1983; 48 FR 37216, Aug. 17, 1983; 49 FR 45145, Nov. 15, 1984; 57 FR 48333, Oct. 23, 1992; 62 FR 51058, Sept. 30, 1997]

(a) Applications for FM broadcast authorizations must show the field strength contours required by FCC Form 301 or FCC Form 340, as appropriate.

(b) The field strength contours provided for in this section shall be considered for the following purposes only:

(1) In the estimation of coverage resulting from the selection of a particular transmitter site by an applicant for an FM broadcast station.

(2) In connection with problems of coverage arising out of application of §73.3555.

(3) In determining compliance with §73.315(a) concerning the minimum field strength to be provided over the principal community to be served.

(4) In determining compliance with §73.215 concerning contour protection.

[28 FR 13623, Dec. 14, 1963, as amended at 31 FR 10126, July 27, 1966; 32 FR 11471, Aug. 9, 1967; 52 FR 10570, Apr. 2, 1987; 54 FR 9802, Mar. 8, 1989]

(a) In the preparation of the profile graphs previously described, and in determining the location and height above mean sea level of the antenna site, the elevation or contour intervals shall be taken from United States Geological Survey Topographic Quadrangle Maps, United States Army Corps of Engineers Maps or Tennessee Valley Authority maps, whichever is the latest, for all areas for which such maps are available. If such maps are not published for the area in question, the next best topographic information should be used. Topographic data may sometimes be obtained from state and municipal agencies. The data from the Sectional Aeronautical Charts (including bench marks) or railroad depot elevations and highway elevations from road maps may be used where no better information is available. In cases where limited topographic data can be obtained, use may be made of an altimeter in a car driven along roads extending generally radially from the transmitter site.

(b) The Commission will not ordinarily require the submission of topographical maps for areas beyond 24 km (15 miles) from the antenna site, but the maps must include the principal city or cities to be served. If it appears necessary, additional data may be requested.

(c) The U.S. Geological Survey Topography Quadrangle Sheets may be obtained from the U.S. Geological Survey Department of the Interior, Washington, DC 20240. The Sectional Aeronautical Charts are available from the U.S. Coast and Geodetic Survey, Department of Commerce, Washington, DC 20235. These maps may also be secured from branch offices and from authorized agents or dealers in most principal cities.

(d) In lieu of maps, the average terrain elevation may be computer generated except in cases of dispute, using elevations from a 30 second, point or better topographic data file. The file must be identified and the data processed for intermediate points along each radial using linear interpolation techniques. The height above mean sea level of the antenna site must be obtained manually using appropriate topographic maps.

[28 FR 13623, Dec. 14, 1963, as amended at 31 FR 10126, July 27, 1966; 49 FR 48937, Dec. 17, 1984; 58 FR 44950, Aug. 25, 1993; 63 FR 33877, June 22, 1998]

(a) All predictions of coverage made pursuant to this section shall be made without regard to interference and shall be made only on the basis of estimated field strengths.

(b) Predictions of coverage shall be made only for the same purposes as relate to the use of field strength contours as specified in §73.311.

(c) In predicting the distance to the field strength contours, the F(50,50) field strength chart, Figure 1 of §73.333 must be used. The 50% field strength is defined as that value exceeded for 50% of the time.

(1) The F(50,50) chart gives the estimated 50% field strengths exceeded at 50% of the locations in dB above 1 uV/m. The chart is based on an effective power radiated from a half-wave dipole antenna in free space, that produces an unattenuated field strength at 1 kilometer of about 107 dB above 1 uV/m (221.4 mV/m).

(2) To use the chart for other ERP values, convert the ordinate scale by the appropriate adjustment in dB. For example, the ordinate scale for an ERP of 50 kW should be adjusted by 17 dB [10 log (50 kW) = 17 dBk], and therefore a field strength of 60 dBu would correspond to the field strength value at (60−17 =) 44 dBu on the chart. When predicting the distance to field strength contours, use the maximum ERP of the main radiated lobe in the pertinent azimuthal direction (do not account for beam tilt). When predicting field strengths over areas not in the plane of the maximum main lobe, use the ERP in the direction of such areas, determined by considering the appropriate vertical radiation pattern.

(d) The antenna height to be used with this chart is the height of the radiation center of the antenna above the average terrain along the radial in question. In determining the average elevation of the terrain, the elevations between 3 and 16 kilometers from the antenna site are used.

(1) Profile graphs must be drawn for eight radials beginning at the antenna site and extending 16 kilometers therefrom. The radials should be drawn for each 45° of azimuth starting with True North. At least one radial must include the principal community to be served even though it may be more than 16 kilometers from the antenna site. However, in the event none of the evenly spaced radials include the principal community to be served, and one or more such radials are drawn in addition, these radials must not be used in computing the antenna height above average terrain.

(2) Where the 3 to 16 kilometers portion of a radial extends in whole or in part over a large body of water or extends over foreign territory but the 50 uV/m (34 dBu) contour encompasses land area within the United States beyond the 16 kilometers portion of the radial, the entire 3 to 16 kilometers portion of the radial must be included in the computation of antenna height above average terrain. However, where the 50 uV/m (34 dBu) contour does not so encompass United States land area, and (i) the entire 3 to 16 kilometers portion of the radial extends over large bodies of water or over foreign territory, such radial must be completely omitted from the computation of antenna height above average terrain, and (ii) where a part of the 3 to 16 kilometers portion of a radial extends over large bodies of water or foreign territory, only that part of the radial extending from 3 kilometers to the outermost portion of land in the United States covered by the radial used must be used in the computation of antenna height above average terrain.

(3) The profile graph for each radial should be plotted by contour intervals of from 12 to 30 meters and, where the data permits, at least 50 points of elevation (generally uniformly spaced) should be used for each radial. In instances of very rugged terrain where the use of contour intervals of 30 meters would result in several points in a short distance, 60 or 120 meter contour intervals may be used for such distances. On the other hand, where the terrain is uniform or gently sloping the smallest contour interval indicated on the topographic map should be used, although only relatively few points may be available. The profile graph should indicate the topography accurately for each radial, and the graphs should be plotted with the distance in kilometers as the abscissa and the elevation in meters above mean sea level as the ordinate. The profile graphs should indicate the source of the topographical data used. The graph should also show the elevation of the center of the radiating system. The graph may be plotted either on rectangular coordinate paper or on special paper that shows the curvature of the earth. It is not necessary to take the curvature of the earth into consideration in this procedure as this factor is taken care of in the charts showing signal strengths. The average elevation of the 13 kilometer distance between 3 and 16 kilometers from the antenna site should then be determined from the profile graph for each radial. This may be obtained by averaging a large number of equally spaced points, by using a planimeter, or by obtaining the median elevation (that exceeded for 50% of the distance) in sectors and averaging those values.

(4) Examples of HAAT calculations:

(i) The heights above average terrain on the eight radials are as follows:

The antenna height above terrain (defined in §73.310(a)) is computed as follows:

(120 + 255 + 185 + 90 − 10 − 85 + 40 + 85) / 8 = 85 meters.

(ii) Same as paragraph (d)(4)(i) of this section, except the 0° radial is entirely over sea water. The antenna height above average terrain is computed as follows (note that the divisor is 7 not 8):

(255 + 185 + 90 − 10 − 85 + 40 + 85) / 7 = 80 meters.

(iii) Same as paragraph (d)(4)(i) of this section, except that only the first 10 kilometers of the 90° radial are in the United States; beyond 10 kilometers the 90° radial is in a foreign country. The height above average terrain of the 3 to 10 kilometer portion of the 90° radial is 105 meters. The antenna height above average terrain is computed as follows (note that the divisor is 8 not 7.5):

(120 + 255 + 105 + 90 − 10 − 85 + 40 + 85) / 8 = 75 meters.

(e) In cases where the terrain in one or more directions from the antenna site departs widely from the average elevation of the 3 to 16 kilometer sector, the prediction method may indicate contour distances that are different from what may be expected in practice. For example, a mountain ridge may indicate the practical limit of service although the prediction method may indicate otherwise. In such cases, the prediction method should be followed, but a supplemental showing may be made concerning the contour distances as determined by other means. Such supplemental showings should describe the procedure used and should include sample calculations. Maps of predicted coverage should include both the coverage as predicted by the regular method and as predicted by a supplemental method. When measurements of area are required, these should include the area obtained by the regular prediction method and the area obtained by the supplemental method. In directions where the terrain is such that antenna heights less than 30 meters for the 3 to 16 kilometer sector are obtained, an assumed height of 30 meters must be used for the prediction of coverage. However, where the actual contour distances are critical factors, a supplemental showing of expected coverage must be included together with a description of the method used in predicting such coverage. In special cases, the FCC may require additional information as to terrain and coverage.

(f) The effect of terrain roughness on the predicted field strength of a signal at points distant from an FM transmitting antenna is assumed to depend on the magnitude of a terrain roughness factor (h) which, for a specific propagation path, is determined by the characteristics of a segment of the terrain profile for that path 40 kilometers in length located between 10 and 50 kilometers from the antenna. The terrain roughness factor has a value equal to the distance, in meters, between elevations exceeded by all points on the profile for 10% and 90% respectively, of the length of the profile segment. (See §73.333, Figure 4.)

(g) If the lowest field strength value of interest is initially predicted to occur over a particular propagation path at a distance that is less than 50 kilometers from the antenna, the terrain profile segment used in the determination of terrain roughness factor over that path must be that included between points 10 kilometers from the transmitter and such lesser distances. No terrain roughness correction need be applied when all field strength values of interest are predicted to occur 10 kilometers or less from the transmitting antenna.

(h) Profile segments prepared for terrain roughness factor determinations are to be plotted in rectangular coordinates, with no less than 50 points evenly spaced within the segment using data obtained from topographic maps with contour intervals of approximately 15 meters (50 feet) or less if available.

(i) The field strength charts (§73.333, Figs. 1–1a) were developed assuming a terrain roughness factor of 50 meters, which is considered to be representative of average terrain in the United States. Where the roughness factor for a particular propagation path is found to depart appreciably from this value, a terrain roughness correction (ΔF) should be applied to field strength values along this path, as predicted with the use of these charts. The magnitude and sign of this correction, for any value of Δh, may be determined from a chart included in §73.333 as Figure 5.

(j) Alternatively, the terrain roughness correction may be computed using the following formula:

ΔF=1.9−0.03(Δh)(1+f/300)

Where:

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13623, Dec. 14, 1963, as amended at 40 FR 27678, July 1, 1975; 48 FR 29507, June 27, 1983; 52 FR 11655, Apr. 10, 1987; 52 FR 37789, Oct. 9, 1987; 57 FR 48333, Oct. 23, 1992; 63 FR 33877, June 22, 1998]

Effective Date Note:  At 42 FR 25736, May 19, 1977, the effective date of §73.313 paragraphs (i) and (j) was stayed indefinitely.

§ 73.314   Field strength measurements.

(a) Except as provided for in §73.209, FM broadcast stations shall not be protected from any type of interference or propagation effect. Persons desiring to submit testimony, evidence or data to the Commission for the purpose of showing that the technical standards contained in this subpart do not properly reflect the levels of any given type of interference or propagation effect may do so only in appropriate rule making proceedings concerning the amendment of such technical standards. Persons making field strength measurements for formal submission to the Commission in rule making proceedings, or making such measurements upon the request of the Commission, shall follow the procedure for making and reporting such measurements outlined in paragraph (b) of this section. In instances where a showing of the measured level of a signal prevailing over a specific community is appropriate, the procedure for making and reporting field strength measurements for this purpose is set forth in paragraph (c) of this section.

(b) Collection of field strength data for propagation analysis.

(1) Preparation for measurements. (i) On large scale topographic maps, eight or more radials are drawn from the transmitter location to the maximum distance at which measurements are to be made, with the angles included between adjacent radials of approximately equal size. Radials should be oriented so as to traverse representative types of terrain. The specific number of radials and their orientation should be such as to accomplish this objective.

(ii) Each radial is marked, at a point exactly 16 kilometers from the transmitter and, at greater distances, at successive 3 kilometer intervals. Where measurements are to be conducted over extremely rugged terrain, shorter intervals may be used, but all such intervals must be of equal length. Accessible roads intersecting each radial as nearly as possible at each 3 kilometer marker are selected. These intersections are the points on the radial at which measurements are to be made, and are referred to subsequently as measuring locations. The elevation of each measuring location should approach the elevation at the corresponding 3 kilometer marker as nearly as possible.

(2) Measurement procedure. All measurements must be made utilizing a receiving antenna designed for reception of the horizontally polarized signal component, elevated 9 meters above the roadbed. At each measuring location, the following procedure must be used:

(i) The instrument calibration is checked.

(ii) The antenna is elevated to a height of 9 meters.

(iii) The receiving antenna is rotated to determine if the strongest signal is arriving from the direction of the transmitter.

(iv) The antenna is oriented so that the sector of its response pattern over which maximum gain is realized is in the direction of the transmitter.

(v) A mobile run of at least 30 meters is made, that is centered on the intersection of the radial and the road, and the measured field strength is continuously recorded on a chart recorder over the length of the run.

(vi) The actual measuring location is marked exactly on the topographic map, and a written record, keyed to the specific location, is made of all factors which may affect the recorded field, such as topography, height and types of vegetation, buildings, obstacles, weather, and other local features.

(vii) If, during the test conducted as described in paragraph (b)(2)(iii) of this section, the strongest signal is found to come from a direction other than from the transmitter, after the mobile run prescribed in paragraph (b)(2)(v) of this section is concluded, additional measurements must be made in a “cluster” of at least five fixed points. At each such point, the field strengths with the antenna oriented toward the transmitter, and with the antenna oriented so as to receive the strongest field, are measured and recorded. Generally, all points should be within 60 meters of the center point of the mobile run.

(viii) If overhead obstacles preclude a mobile run of at least 30 meters, a “cluster” of five spot measurements may be made in lieu of this run. The first measurement in the cluster is identified. Generally, the locations for other measurements must be within 60 meters of the location of the first.

(3) Method of reporting measurements. A report of measurements to the Commission shall be submitted in affidavit form, in triplicate, and should contain the following information:

(i) Tables of field strength measurements, which, for each measuring location, set forth the following data:

(A) Distance from the transmitting antenna.

(B) Ground elevation at measuring location.

(C) Date, time of day, and weather.

(D) Median field in dBu for 0 dBk, for mobile run or for cluster, as well as maximum and minimum measured field strengths.

(E) Notes describing each measuring location.

(ii) U.S. Geological Survey topographic maps, on which is shown the exact location at which each measurement was made. The original plots shall be made on maps of the largest available scale. Copies may be reduced in size for convenient submission to the Commission, but not to the extent that important detail is lost. The original maps shall be made available, if requested. If a large number of maps is involved, an index map should be submitted.

(iii) All information necessary to determine the pertinent characteristics of the transmitting installation, including frequency, geographical coordinates of antenna site, rated and actual power output of transmitter, measured transmission line loss, antenna power gain, height of antenna above ground, above mean sea level, and above average terrain. The effective radiated power should be computed, and horizontal and vertical plane patterns of the transmitting antenna should be submitted.

(iv) A list of calibrated equipment used in the field strength survey, which, for each instrument, specifies its manufacturer, type, serial number and rated accuracy, and the date of its most recent calibration by the manufacturer, or by a laboratory. Complete details of any instrument not of standard manufacture shall be submitted.

(v) A detailed description of the calibration of the measuring equipment, including field strength meters, measuring antenna, and connecting cable.

(vi) Terrain profiles in each direction in which measurements were made, drawn on curved earth paper for equivalent 4/3 earth radius, of the largest available scale.

(c) Collection of field strength data to determine FM broadcast service in specific communities.

(1) Preparation for measurement. (i) The population (P) of the community, and its suburbs, if any, is determined by reference to an appropriate source, e.g., the 1970 U.S. Census tables of population of cities and urbanized areas.

(ii) The number of locations at which measurements are to be made shall be at least 15, and shall be approximately equal to 0.1(P)^1/2, if this product is a number greater than 15.

(iii) A rectangular grid, of such size and shape as to encompass the boundaries of the community is drawn on an accurate map of the community. The number of line intersections on the grid included within the boundaries of the community shall be at least equal to the required number of measuring locations. The position of each intersection on the community map determines the location at which a measurement shall be made.

(2) Measurement procedure. All measurements must be made using a receiving antenna designed for reception of the horizontally polarized signal component, elevated 9 meters above ground level.

(i) Each measuring location shall be chosen as close as feasible to a point indicated on the map, as previously prepared, and at as nearly the same elevation as that point as possible.

(ii) At each measuring location, after equipment calibration and elevation of the antenna, a check is made to determine whether the strongest signal arrives from a direction other than from the transmitter.

(iii) At 20 percent or more of the measuring locations, mobile runs, as described in paragraph (b)(2) of this section shall be made, with no less than three such mobile runs in any case. The points at which mobile measurements are made shall be well separated. Spot measurements may be made at other measuring points.

(iv) Each actual measuring location is marked exactly on the map of the community, and suitably keyed. A written record shall be maintained, describing, for each location, factors which may affect the recorded field, such as the approximate time of measurement, weather, topography, overhead wiring, heights and types of vegetation, buildings and other structures. The orientation, with respect to the measuring location shall be indicated of objects of such shape and size as to be capable of causing shadows or reflections. If the strongest signal received was found to arrive from a direction other than that of the transmitter, this fact shall be recorded.

(3) Method of reporting measurements. A report of measurements to the Commission shall be submitted in affidavit form, in triplicate, and should contain the following information:

(i) A map of the community showing each actual measuring location, specifically identifying the points at which mobile runs were made.

(ii) A table keyed to the above map, showing the field strength at each measuring point, reduced to dBu for the actual effective radiated power of the station. Weather, date, and time of each measurement shall be indicated.

(iii) Notes describing each measuring location.

(iv) A topographic map of the largest available scale on which are marked the community and the transmitter site of the station whose signals have been measured, which includes all areas on or near the direct path of signal propagation.

(v) Computations of the mean and standard deviation of all measured field strengths, or a graph on which the distribution of measured field strength values is plotted.

(vi) A list of calibrated equipment used for the measurements, which for each instrument, specifies its manufacturer, type, serial number and rated accuracy, and the date of its most recent calibration by the manufacturer, or by a laboratory. Complete details of any instrument not of standard manufacture shall be submitted.

(vii) A detailed description of the procedure employed in the calibration of the measuring equipment, including field strength meters, measuring antenna, and connecting cable.

[40 FR 27682, July 1, 1975; 40 FR 28802, July 9, 1975, as amended at 48 FR 29508, June 27, 1983]

(a) The transmitter location shall be chosen so that, on the basis of the effective radiated power and antenna height above average terrain employed, a minimum field strength of 70 dB above one uV/m (dBu), or 3.16 mV/m, will be provided over the entire principal community to be served.

(b) The transmitter location should be chosen to maximize coverage to the city of license while minimizing interference. This is normally accomplished by locating in the least populated area available while maintaining the provisions of paragraph (a) of this section. In general, the transmitting antenna of a station should be located in the most sparsely populated area available at the highest elevation available. The location of the antenna should be so chosen that line-of-sight can be obtained from the antenna over the principle city or cities to be served; in no event should there be a major obstruction in this path.

(c) The transmitting location should be selected so that the 1 mV/m contour encompasses the urban population within the area to be served. It is recognized that topography, shape of the desired service area, and population distribution may make the choice of a transmitter location difficult. In such cases consideration may be given to the use of a directional antenna system, although it is generally preferable to choose a site where a nondirectional antenna may be employed.

(d) In cases of questionable antenna locations it is desirable to conduct propagation tests to indicate the field strength expected in the principal city or cities to be served and in other areas, particularly where severe shadow problems may be expected. In considering applications proposing the use of such locations, the Commission may require site tests to be made. Such tests should include measurements made in accordance with the measurement procedures described in §73.314, and full data thereon shall be supplied to the Commission. The test transmitter should employ an antenna having a height as close as possible to the proposed antenna height, using a balloon or other support if necessary and feasible. Information concerning the authorization of site tests may be obtained from the Commission upon request.

(e) Cognizance must of course be taken regarding the possible hazard of the proposed antenna structure to aviation and the proximity of the proposed site to airports and airways. Procedures and standards with respect to the Commission's consideration of proposed antenna structures which will serve as a guide to persons intending to apply for radio station licenses are contained in Part 17 of this chapter (Construction, Marking, and Lighting of Antenna Structures).

[28 FR 13623, Dec. 14, 1963, as amended at 41 FR 22943, June 8, 1976; 49 FR 38131, Sept. 27, 1984; 49 FR 45146, Nov. 15, 1984; 51 FR 9965, Mar. 24, 1986; 52 FR 10570, Apr. 2, 1987; 65 FR 79778, Dec. 20, 2000]

(a) It shall be standard to employ horizontal polarization; however, circular or elliptical polarization may be employed if desired. Clockwise or counterclockwise rotation may be used. The supplemental vertically polarized effective radiated power required for circular or elliptical polarization shall in no event exceed the effective radiated power authorized.

(b) Directional antennas. A directional antenna is an antenna that is designed or altered for the purpose of obtaining a non-circular radiation pattern.

(1) Applications for the use of directional antennas that propose a ratio of maximum to minimum radiation in the horizontal plane of more than 15 dB will not be accepted.

(2) Directional antennas used to protect short-spaced stations pursuant to §73.213 or §73.215 of the rules, that have a radiation pattern which varies more than 2 dB per 10 degrees of azimuth will not be authorized.

(c) Applications for directional antennas. (1) Applications for construction permit proposing the use of directional antenna systems must include a tabulation of the composite antenna pattern for the proposed directional antenna. A value of 1.0 must be used to correspond to the direction of maximum radiation. The pattern must be tabulated such that 0° corresponds to the direction of maximum radiation or alternatively, in the case of an asymmetrical antenna pattern, the pattern must be tabulated such that 0° corresponds to the actual azimuth with respect to true North. In the case of a composite antenna composed of two or more individual antennas, the pattern required is that for the composite antenna, not the patterns for each of the individual antennas. Applications must include valuations tabulated at intervals of not greater than ten (10) degrees. In addition, tabulated values of all maximas and minimas, with their corresponding azimuths, must be submitted.

(2) Applications for license upon completion of antenna construction must include the following:

(i) A complete description of the antenna system, including the manufacturer and model number of the directional antenna. It is not sufficient to label the antenna with only a generic term such as “dipole.” In the case of individually designed antennas with no model number, or in the case of a composite antenna composed of two or more individual antennas, the antenna must be described as a “custom” or “composite” antenna, as appropriate. A full description of the design of the antenna must also be submitted.

(ii) A plot of the composite pattern of the directional antenna. A value of 1.0 must be used to correspond to the direction of maximum radiation. The plot of the pattern must be oriented such that 0° corresponds to the direction of maximum radiation or alternatively, in the case of an asymmetrical antenna pattern, the plot must be oriented such that 0° corresponds to the actual azimuth with respect to true North. The horizontal plane pattern must be plotted to the largest scale possible on unglazed letter-size polar coordinate paper (main engraving approximately 18 cm × 25 cm (7 inches × 10 inches)) using only scale divisions and subdivisions of 1, 2, 2.5, or 5 times 10-nth. Values of field strength less than 10% of the maximum field strength plotted on that pattern must be shown on an enlarged scale. In the case of a composite antenna composed of two or more individual antennas, the composite antenna pattern should be provided, and not the pattern for each of the individual antennas.

(iii) A tabulation of the measured relative field pattern required in paragraph (c)(1) of this section. The tabulation must use the same zero degree reference as the plotted pattern, and must contain values for at least every 10 degrees. Sufficient vertical patterns to indicate clearly the radiation characteristics of the antenna above and below the horizontal plane. Complete information and patterns must be provided for angles of −10 deg. from the horizontal plane and sufficient additional information must be included on that portion of the pattern lying between +10 deg. and the zenith and −10 deg. and the nadir, to conclusively demonstrate the absence of undesirable lobes in these areas. The vertical plane pattern must be plotted on rectangular coordinate paper with reference to the horizontal plane. In the case of a composite antenna composed of two or more individual antennas, the composite antenna pattern should be used, and not the pattern for each of the individual antennas.

(iv) A statement that the antenna is mounted on the top of an antenna tower recommended by the antenna manufacturer, or is side-mounted on a particular type of antenna tower in accordance with specific instructions provided by the antenna manufacturer.

(v) A statement that the directional antenna is not mounted on the top of an antenna tower which includes a top-mounted platform larger than the nominal cross-sectional area of the tower in the horizontal plane.

(vi) A statement that no other antenna of any type is mounted on the same tower level as a directional antenna, and that no antenna of any type is mounted within any horizontal or vertical distance specified by the antenna manufacturer as being necessary for proper directional operation.

(vii) A statement from an engineer listing such individual engineer's qualifications and certifying that the antenna has been installed pursuant to the manufacturer's instructions.

(viii) A statement from a licensed surveyor that the installed antenna is properly oriented.

(ix)(A) For a station authorized pursuant to §73.215 or Sec. §73.509, a showing that the root mean square (RMS) of the measured composite antenna pattern (encompassing both the horizontally and vertically polarized radiation components (in relative field)) is at least 85 percent of the RMS of the authorized composite directional antenna pattern (in relative field). The RMS value, for a composite antenna pattern specified in relative field values, may be determined from the following formula:

RMS=the square root of:

[(relative field value 1)² + (relative field value 2)² +....+ (last relative field value)² ]

total number of relative field values

(B) where the relative field values are taken from at least 36 evenly spaced radials for the entire 360 degrees of azimuth. The application for license must also demonstrate that coverage of the community of license by the 70 dBu contour is maintained for stations authorized pursuant to §73.215 on Channels 221 through 300, as required by §73.315(a), while noncommercial educational stations operating on Channels 201 through 220 must show that the 60 dBu contour covers at least a portion of the community of license.

(d) Applications proposing the use of FM transmitting antennas in the immediate vicinity (i.e. 60 meters or less) of other FM or TV broadcast antennas must include a showing as to the expected effect, if any, of such approximate operation.

(e) Where an FM licensee or permittee proposes to mount its antenna on an AM antenna tower, or locate within 3.2 km of an AM antenna tower, the FM licensee or permittee must comply with §73.1692.

[28 FR 13623, Dec. 14, 1963, as amended at 34 FR 14222, Sept. 10, 1969; 37 FR 25841, Dec. 5, 1972; 43 FR 53738, Nov. 17, 1978; 48 FR 29508, June 27, 1983; 51 FR 17028, May 8, 1986; 54 FR 9804, Mar. 8, 1989; 56 FR 57294, Nov. 8, 1991; 62 FR 51058, Sept. 30, 1997; 63 FR 70047, Dec. 18, 1998]

(a) FM broadcast stations employing transmitters authorized after January 1, 1960, must maintain the bandwidth occupied by their emissions in accordance with the specification detailed below. FM broadcast stations employing transmitters installed or type accepted before January 1, 1960, must achieve the highest degree of compliance with these specifications practicable with their existing equipment. In either case, should harmful interference to other authorized stations occur, the licensee shall correct the problem promptly or cease operation.

(b) Any emission appearing on a frequency removed from the carrier by between 120 kHz and 240 kHz inclusive must be attenuated at least 25 dB below the level of the unmodulated carrier. Compliance with this requirement will be deemed to show the occupied bandwidth to be 240 kHz or less.

(c) Any emission appearing on a frequency removed from the carrier by more than 240 kHz and up to and including 600 kHz must be attenuated at least 35 dB below the level of the unmodulated carrier.

(d) Any emission appearing on a frequency removed from the carrier by more than 600 kHz must be attenuated at least 43 + 10 Log₁₀ (Power, in watts) dB below the level of the unmodulated carrier, or 80 dB, whichever is the lesser attenuation.

(e) Preemphasis shall not be greater than the impedance-frequency characteristics of a series inductance resistance network having a time constant of 75 microseconds. (See upper curve of Figure 2 of §73.333.)

[51 FR 17028, May 8, 1986]

Areas adjacent to the transmitting antenna that receive a signal with a strength of 115 dBu (562 mV/m) or greater will be assumed to be blanketed. In determining the blanketed area, the 115 dBu contour is determined by calculating the inverse distance field using the effective radiated power of the maximum radiated lobe of the antenna without considering its vertical radiation pattern or height. For directional antennas, the effective radiated power in the pertinent bearing shall be used.

(a) The distance to the 115 dBu contour is determined using the following equation:

D (in kilometers)=0.394√ P

D (in miles)=0.245√ P

Where P is the maximum effective radiated power (ERP), measured in kilowatts, of the maximum radiated lobe.

(b) After January 1, 1985, permittees or licensees who either (1) commence program tests, or (2) replace their antennas, or (3) request facilities modifications and are issued a new construction permit must satisfy all complaints of blanketing interference which are received by the station during a one year period. The period begins with the commencement of program tests, or commencement of programming utilizing the new antenna. Resolution of complaints shall be at no cost to the complainant. These requirements specifically do not include interference complaints resulting from malfunctioning or mistuned receivers, improperly installed antenna systems, or the use of high gain antennas or antenna booster amplifiers. Mobile receivers and non-RF devices such as tape recorders or hi-fi amplifiers (phonographs) are also excluded.

(c) A permittee collocating with one or more existing stations and beginning program tests on or after January 1, 1985, must assume full financial responsibility for remedying new complaints of blanketing interference for a period of one year. Two or more permittees that concurrently collocate on or after January 1, 1985, shall assume shared responsibility for remedying blanketing complaints within the blanketing area unless an offending station can be readily determined and then that station shall assume full financial responsibility.

(d) Following the one year period of full financial obligation to satisfy blanketing complaints, licensees shall provide technical information or assistance to complainants on remedies for blanketing interference.

[28 FR 13623, Dec. 14, 1963, as amended at 52 FR 25866, July 9, 1987]

(a) The technical specifications in this Section apply to all transmissions of FM multiplex subcarriers except those used for stereophonic sound broadcasts under the provisions of §73.322.

(b) Modulation. Any form of modulation may be used for subcarrier operation.

(c) Subcarrier baseband. (1) During monophonic program transmissions, multiplex subcarriers and their significant sidebands must be within the range of 20 kHz to 99 kHz.

(2) During stereophonic sound program transmissions (see §73.322), multiplex subcarriers and their significant sidebands must be within the range of 53 kHz to 99 kHz.

(3) During periods when broadcast programs are not being transmitted, multiplex subcarriers and their significant sidebands must be within the range of 20 kHz to 99 kHz.

(d) Subcarrier injection. (1) During monophonic program transmissions, modulation of the carrier by the arithmetic sum of all subcarriers may not exceed 30% referenced to 75 kHz modulation deviation. However, the modulation of the carrier by the arithmetic sum of all subcarriers above 75 kHz may not modulate the carrier by more than 10%.

(2) During stereophonic program transmissions, modulation of the carrier by the arithmetic sum of all subcarriers may not exceed 20% referenced to 75 kHz modulation deviation. However, the modulation of the carrier by the arithmetic sum of all subcarriers above 75 kHz may not modulate the carrier by more than 10%.

(3) During periods when no broadcast program service is transmitted, modulation of the carrier by the arithmetic sum of all subcarriers may not exceed 30% referenced to 75 kHz modulation deviation. However, the modulation of the carrier by the arithmetic sum of all subcarriers above 75 kHz may not modulate the carrier by more than 10%.

(4) Total modulation of the carrier wave during transmission of multiplex subcarriers used for subsidiary communications services must comply with the provisions §73.1570(b).

(e) Subcarrier generators may be installed and used with a type accepted FM broadcast transmitter without specific authorization from the FCC provided the generator can be connected to the transmitter without requiring any mechanical or electrical modifications in the transmitter FM exciter circuits.

(f) Stations installing multiplex subcarrier transmitting equipment must ensure the proper suppression of spurious or harmonic radiations. See §§73.317, 73.1590 and 73.1690. If the subcarrier operation causes the station's transmissions not to comply with the technical provisions for FM broadcast stations or causes harmful interference to other communication services, the licensee or permittee must correct the problem promptly or cease operation. The licensee may be required to verify the corrective measures with supporting data. Such data must be retained at the station and be made available to the FCC upon request.

[48 FR 28455, June 22, 1983, as amended at 48 FR 37216, Aug. 17, 1983; 49 FR 15080, Apr. 17, 1984; 49 FR 38131, Sept. 27, 1984; 50 FR 1534, Jan. 11, 1985; 51 FR 17029, May 8, 1986; 57 FR 48333, Oct. 23, 1992]

(a) An FM broadcast station shall not use 19 kHz ±20 Hz, except as the stereophonic pilot frequency in a transmission system meeting the following parameters:

(1) The modulating signal for the main channel consists of the sum of the right and left signals.

(2) The pilot subcarrier at 19 kHz ±2 Hz, must frequency modulate the main carrier between the limits of 8 and 10 percent.

(3) One stereophonic subcarrier must be the second harmonic of the pilot subcarrier (i.e., 38 kHz) and must cross the time axis with a positive slope simultaneously with each crossing of the time axis by the pilot subcarrier. Additional stereophomic subcarriers are not precluded.

(4) Double sideband, suppressed-carrier, amplitude modulation of the stereophonic subcarrier at 38 kHz must be used.

(5) The stereophonic subcarrier at 38 kHz must be suppressed to a level less than 1% modulation of the main carrier.

(6) The modulating signal for the required stereophonic subcarrier must be equal to the difference of the left and right signals.

(7) The following modulation levels apply:

(i) When a signal exists in only one channel of a two channel (biphonic) sound transmission, modulation of the carrier by audio components within the baseband range of 50 Hz to 15 kHz shall not exceed 45% and modulation of the carrier by the sum of the amplitude modulated subcarrier in the baseband range of 23 kHz to 53 kHz shall not exceed 45%.

(ii) When a signal exists in only one channel of a stereophonic sound transmission having more than one stereophonic subcarrier in the baseband, the modulation of the carrier by audio components within the audio baseband range of 23 kHz to 99 kHz shall not exceed 53% with total modulation not to exceed 90%.

(b) Stations not transmitting stereo with the method described in (a), must limit the main carrier deviation caused by any modulating signals occupying the band 19 kHz ±20 Hz to 125 Hz.

(c) All stations, regardless of the stereophonic transmission system used, must not exceed the maximum modulation limits specified in §73.1570(b)(2). Stations not using the method described in (a), must limit the modulation of the carrier by audio components within the audio baseband range of 23 kHz to 99 kHz to not exceed 53%.

[51 FR 17029, May 8, 1986]

This section consists of the following Figures 1, 1a, 2, and slider 4 and 5.

Note: The figures reproduced herein, due to their small scale, are not to be used in connection with material submitted to the F.C.C.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13623, Dec. 14, 1963, as amended at 35 FR 2591, Feb. 5, 1970; 40 FR 27679, July 1, 1975; 45 FR 28141, Apr. 28, 1980; 48 FR 29508, June 27, 1983; 49 FR 19670, May 9, 1984]

Effective Date Note:  At 42 FR 25736, May 19, 1977, in §73.333, the effective date of Figures 4 and 5 was stayed indefinitely.

Subpart C—Noncommercial Educational FM Broadcast Stations

(a) The following frequencies, except as provided in paragraph (b) of this section, are available for noncommercial educational FM broadcasting:

(b) In Alaska, FM broadcast stations operating on Channels 200–220 (87.9–91.9 MHz) shall not cause harmful interference to and must accept interference from non-Government fixed operations authorized prior to January 1, 1982.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[43 FR 39715, Sept. 6, 1978, as amended at 47 FR 30068, July 12, 1982; 52 FR 43765, Nov. 16, 1987; 58 FR 44950, Aug. 25, 1993]

The operation of, and the service furnished by noncommercial educational FM broadcast stations shall be governed by the following:

(a) A noncommercial educational FM broadcast station will be licensed only to a nonprofit educational organization and upon showing that the station will be used for the advancement of an educational program.

(1) In determining the eligibility of publicly supported educational organizations, the accreditation of their respective state departments of education shall be taken into consideration.

(2) In determining the eligibility of privately controlled educational organizations, the accreditation of state departments of education and/or recognized regional and national educational accrediting organizations shall be taken into consideration.

(b) Each station may transmit programs directed to specific schools in a system or systems for use in connection with the regular courses as well as routine and administrative material pertaining thereto and may transmit educational, cultural, and entertainment programs to the public.

(c) A noncommercial educational FM broadcast station may broadcast programs produced by, or at the expense of, or furnished by persons other than the licensee, if no other consideration than the furnishing of the program and the costs incidental to its production and broadcast are received by the licensee. The payment of line charges by another station network, or someone other than the licensee of a noncommercial educational FM broadcast station, or general contributions to the operating costs of a station, shall not be considered as being prohibited by this paragraph.

(d) Each station shall furnish a nonprofit and noncommercial broadcast service. Noncommercial educational FM broadcast stations are subject to the provisions of §73.1212 to the extent they are applicable to the broadcast of programs produced by, or at the expense of, or furnished by others. No promotional announcement on behalf of for profit entities shall be broadcast at any time in exchange for the receipt, in whole or in part, of consideration to the licensee, its principals, or employees. However, acknowledgements of contributions can be made. The scheduling of any announcements and acknowledgements may not interrupt regular programming.

(e) Mutually exclusive applications for noncommercial educational radio stations operating on reserved channels will be resolved pursuant to the point system in subpart K.

Note to §73.503: Commission interpretation on this rule, including the acceptable form of acknowledgements, may be found in the Second Report and Order in Docket No. 21136 (Commission Policy Concerning the Noncommercial Nature of Educational Broadcast Stations), 86 FCC 2d 141 (1981); the Memorandum Opinion and Order in Docket No. 21136, 90 FCC 2d 895 (1982), and the Memorandum Opinion and Order in Docket 21136, 97 FCC 2d 255 (1984). See also, “Commission Policy Concerning the Noncommercial Nature of Educational Broadcast Stations,” Public Notice, 7 FCC Rcd 827 (1992), which can be retrieved through the Internet at http://www.fcc.gov/mmb/asd/nature.html.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13651, Dec. 14, 1963, as amended at 35 FR 7558, May 15, 1970; 47 FR 36178, Aug. 19, 1982; 49 FR 29069, July 18, 1984; 63 FR 33877, June 22, 1998; 65 FR 36378, June 8, 2000]

(a) NCE-FM stations within 199 miles (320 km) of the United States-Mexican border shall comply with the separation requirements and other provisions of the “Agreement between the United States of America and the United Mexican States Concerning Frequency Modulation Broadcasting in the 88 to 108 MHz Band” as amended.

(b) Applicants for noncommercial educational FM stations within 199 miles (320 km) of the United States-Mexican border shall propose at least Class A minimum facilities (see §73.211(a)). However, existing Class D noncommercial educational stations may apply to change frequency within the educational portion of the FM band in accordance with the requirements set forth in §73.512.

(c) Section 73.208 of this chapter shall be complied with as to the determination of reference points and distance computations used in applications for new or changed facilities. However, if it is necessary to consider a Mexican channel assignment or authorization, the computation of distance will be determined as follows: if a transmitter site has been established, on the basis of the coordinates of the site; if a transmitter site has not been established, on the basis of the reference coordinates of the community, town, or city.

[52 FR 43765, Nov. 16, 1987]

For the purpose of assignment of noncommercial educational FM stations, the United States is divided into three zones, Zone I, Zone I-A, and Zone II, having the boundaries specified in §73.205.

[42 FR 36828, July 18, 1977]

(a) Noncommercial educational stations operating on the channels specified in §73.501 are divided into the following classes:

(1) A Class D educational station is one operating with no more than 10 watts transmitter power output.

(2) A Class D educational (secondary) station is one operating with no more than 10 watts transmitter power output in accordance with the terms of §73.512 or which has elected to follow these requirements before they become applicable under the terms of §73.512.

(3) Noncommercial educational FM (NCE-FM) stations with more than 10 watts transmitter power output are classified as Class A, B1, B, C3, C2, C1, or C depending on the station's effective radiated power and antenna height above average terrain, and on the zone in which the station's transmitter is located, on the same basis as set forth in §§73.210 and 73.211 for commercial stations.

(b) Any noncommercial educational station except Class D may be assigned to any of the channels listed in §73.501. Class D noncommercial educational FM stations applied for or authorized prior to June 1, 1980, may continue to operate on their authorized channels subject to the provisions of §73.512.

[43 FR 39715, Sept. 6, 1978, as amended at 49 FR 10264, Mar. 20, 1984; 52 FR 47569, Dec. 15, 1987; 54 FR 16367, Apr. 24, 1989; 54 FR 19374, May 5, 1989]

(a) Minimum distance separations. No application for a new station, or change in channel or transmitter site or increase in facilities of an existing station, will be granted unless the proposed facilities will be located so as to meet the adjacent channel distance separations specified in §73.207(a) for the class of station involved with respect to assignment on Channels 221, 222, and 223 listed in §73.201 (except where in the case of an existing station the proposed facilities fall within the provisions of §73.207(b)), or where a Class D station is changing frequency to comply with the requirements of §73.512.

(b) Stations authorized as of September 10, 1962, which do not meet the requirements of paragraph (a) of this section and §73.511, may continue to operate as authorized; but any application to change facilities will be subject to the provisions of this section.

(c)(1) Stations separated in frequency by 10.6 or 10.8 MHz (53 or 54 channels) from allotments or assignments on non-reserved channels will not be authorized unless they conform to the separations in Table A given in §73.207.

(2) Under the United States-Mexican FM Broadcasting Agreement, for stations and assignments differing in frequency by 10.6 to 10.8 MHz (53 or 54 channels), U.S. noncommercial educational FM allotments and assignments must meet the separations given in Table C of §73.207 to Mexican allotments or assignments in the border area.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[42 FR 36828, July 18, 1977, as amended at 43 FR 39716, Sept. 6, 1978; 44 FR 65764, Nov. 15, 1979; 49 FR 10264, Mar. 20, 1984; 49 FR 19670, May 9, 1984]

(a) All noncommercial educational stations and LPFM stations operating with more than 10 watts transmitter power output shall be subject to all of the provisions of the FM Technical Standards contained in subpart B of this part. Class D educational stations and LPFM stations operating with 10 watts or less transmitter output power shall be subject to the definitions contained in §73.310, and also to those other provisions of the FM Technical Standards which are specifically made applicable to them by the provisions of this subpart.

(b) The transmitter and associated transmitting equipment of each noncommercial educational FM station and LPFM station licensed for transmitter power output above 10 watts must be designed, constructed and operated in accordance with §73.317.

(c) The transmitter and associated transmitting equipment of each noncommercial educational FM station licensed for transmitter power output of 10 watts or less, although not required to meet all requirements of §73.317, must be constructed with the safety provisions of the current national electrical code as approved by the American National Standards Institute. These stations must be operated, tuned, and adjusted so that emissions are not radiated outside the authorized band causing or which are capable of causing interference to the communications of other stations. The audio distortion, audio frequency range, carrier hum, noise level, and other essential phases of the operation which control the external effects, must be at all times capable of providing satisfactory broadcast service. Studio equipment properly covered by an underwriter's certificate will be considered as satisfying safety requirements.

[65 FR 7640, Feb. 15, 2000]

(a) An application for a new or modified NCE-FM station other than a Class D (secondary) station will not be accepted if the proposed operation would involve overlap of signal strength contours with any other station licensed by the Commission and operating in the reserved band (Channels 200–220, inclusive) as set forth below:

(b) An application by a Class D (secondary) station, other than an application to change class, will not be accepted if the proposed operation would involve overlap of signal strength contours with any other station as set forth below:

(c) The following standards must be used to compute the distances to the pertinent contours:

(1) The distance of the 60 dBu (1 mV/m) contours are to be computed using Figure 1 of §73.333 [F(50,50) curves] of this part.

(2) The distance to the other contours are to be computed using Figure 1a of §73.333 [F(50,10) curves]. In the event that the distance to the contour is below 16 kilometers (approximately 10 miles), and therefore not covered by Figure 1a, curves in Figure 1 must be used.

(3) The effective radiated power (ERP) that is the maximum ERP for any elevation plane on any bearing will be used.

(d) An application for a change (other than a change in channel) in the facilities of a NCE-FM broadcast station will be accepted even though overlap of signal strength contours, as specified in paragraphs (a) and (b) of this section, would occur with another station in an area where such overlap does not already exists, if:

(1) The total area of overlap with that station would not be increased;

(2) The area of overlap with any other station would not increase;

(3) The area of overlap does not move significantly closer to the station receiving the overlap; and,

(4) No area of overlap would be created with any station with which the overlap does not now exist.

(e) The provisions of this section concerning prohibited overlap will not apply where the area of such overlap lies entirely over water.

[50 FR 27962, July 9, 1985, as amended at 52 FR 43765, Nov. 16, 1987; 65 FR 79778, Dec. 20, 2000]

(a) All noncommercial educational stations operating with more than 10 watts transmitter output power shall be subject to the provisions of §73.316 concerning antenna systems contained in subpart B of this part.

(b) Directional antenna. No application for a construction permit of a new station, or change in channel, or change in an existing facility on the same channel will be accepted for filing if a directional antenna with a maximum-to-minimum ratio of more than 15 dB is proposed.

[42 FR 36829, July 18, 1977]

(a) No new noncommercial educational station will be authorized with less power than minimum power requirements for commercial Class A facilities. (See §73.211.)

(b) No new noncommercial educational FM station will be authorized with facilities greater than Class B in Zones I and I-A or Class C in Zone II, as defined in §73.211.

(c) Stations licensed before December 31, 1984, and operating above 50 kW in Zones I and I-A, and above 100 kW and in Zone II may continue to operate as authorized.

[50 FR 27963, July 9, 1985, as amended at 50 FR 31379, Aug. 2, 1985; 54 FR 3602, Jan. 25, 1989]

(a) All Class D stations seeking renewal of license for any term expiring June 1, 1980, or thereafter shall comply with the requirements set forth below and shall simultaneously file an application on FCC Form 340, containing full information regarding such compliance with the provisions set forth below.

(1) To the extent possible, each applicant shall select a commercial FM channel on which it proposes to operate in lieu of the station's present channel. The station may select any commercial channel provided no objectionable interference, as set forth in §73.509(b), would be caused. The application shall include the same engineering information as is required to change the frequency of an existing station and any other information necessary to establish the fact that objectionable interference would not result. If no commerical channel is available where the station could operate without causing such interference, the application shall set forth the basis upon which this conclusion was reached.

(2) If a commercial channel is unavailable, to the extent possible each applicant should propose operation on Channel 200 (87.9 MHz) unless the station would be within 402 kilometers (250 miles) of the Canadian border or 320 kilometers (199 miles) of the Mexican border or would cause interference to an FM station operating on Channels 201, 202, or 203 or to TV Channel 6, as provided in §73.509.

(3) If a channel is not available under either paragraph (a) (1) or (2) of this section, the renewal applicant shall study all 20 noncommercial educational FM channels and shall propose operation on the channel which would cause the least preclusion to the establishment of new stations or increases in power by existing stations. Full information regarding the basis for the selection should be provided.

(b) At any time before the requirements of paragraph (a) become effective, any existing Class D station may file a construction permit application on FCC Form 340 to change channel in the manner described above which shall be subject to the same requirements. In either case, any license granted shall specify that the station's license is for a Class D (secondary) station.

(c) Except in Alaska, no new Class D applications nor major change applications by existing Class D stations are acceptable for filing except by existing Class D stations seeking to change frequency. Upon the grant of such application, the station shall become a Class D (secondary) station.

(d) Class D noncommercial educational (secondary) stations (see §73.506(a)(2)) will be permitted to continue to operate only so long as no interference (as defined in §73.509) is caused to any TV or commercial FM broadcast stations. In the event that the Class D (secondary) station would cause interference to a TV or commercial FM broadcast station after that Class D (secondary) station is authorized, the Class D (secondary) station must cease operation when program tests for the TV or commercial FM broadcast station commence. The Class D (secondary) station may apply for a construction permit (see §73.3533) to change to another frequency or antenna site where it would not cause interference (as defined in §73.509). If the Class D (secondary) station must cease operation before the construction permit is granted, an application for temporary authorization (pursuant to §73.3542) to operate with the proposed facilities may be submitted; where appropriate, such temporary authorization can be granted.

[43 FR 39716, Sept. 6, 1978, as amended at 44 FR 48226, Aug. 17, 1979; 47 FR 28388, June 30, 1982; 50 FR 8326, Mar. 1, 1985]

(a) Noncommercial educational FM stations other than Class D (secondary) which operate on Channels 221 through 300 but which comply with §73.503 as to licensing requirements and the nature of the service rendered, must comply with the provisions of the following sections of subpart B: §§73.201 through 73.213 (Classification of FM Broadcast Stations and Allocations of Frequencies) and such other sections of subpart B as are made specially applicable by the provisions of this subpart C. Stations in Alaska authorized before August 11, 1982, using Channels 261–300 need not meet the minimum effective radiated power requirement specified in §73.211(a). In all other respects, stations operating on Channels 221 through 300 are to be governed by the provisions of this subpart and not subpart B.

(b) When a noncommercial educational applicant is among mutually exclusive applications for an unreserved FM channel, the mutually exclusive applications will be considered pursuant to Subpart I—Competitive Bidding Procedures and not Subpart K—Application and Selection Procedures On Reserved Noncommercial Educational Channels.

[47 FR 30068, July 12, 1982, as amended at 65 FR 36378, June 8, 2000]

Permittees and licensees of NCE FM stations are not protected from interference which may be caused by the grant of a new LPFM station or of authority to modify an existing LPFM station, except as provided in subpart G of this part.

[65 FR 67299, Nov. 9, 2000]

The transmitter location shall be chosen so that, on the basis of effective radiated power and antenna height above average terrain employed, a minimum field strength of l mV/m (60 dBu) will be provided over at least 50 percent of its community of license or reach 50 percent of the population within the community.

[65 FR 79779, Dec. 20, 2000]

The provisions of this section apply to all applications for construction permits for new or modified facilities for a NCE-FM station on Channels 200–220 unless the application is accompanied by a written agreement between the NCE-FM applicant and each affected TV Channel 6 broadcast station concurring with the proposed NCE-FM facilities.

(a) Affected TV Channel 6 Station. (1) An affected TV Channel 6 station is a TV broadcast station which is authorized to operate on Channel 6 that is located within the following distances of a NCE-FM station operating on Channels 201–220:

(2) Where a NCE-FM application has been accepted for filing or granted, the subsequent acceptance of an application filed by a relevant TV Channel 6 station will not require revision of the pending NCE-FM application or the FM station's authorized facilities, unless the provisions of paragraph (e)(3) of this section for TV translator or satellite stations apply.

(b) Existing NCE-FM Stations. (1) A NCE-FM station license authorized to operate on channels 201–220 as of December 31, 1984, or a permittee, granted a construction permit for a NCE-FM station as of December 31, 1984, are not subject to this section unless they propose either:

(i) To make changes in operating facilities or location which will increase predicted interference as calculated under paragraph (e) of this section to TV Channel 6 reception in any direction; or,

(ii) To increase its ratio of vertically polarized to horizontally polarized transmissions.

(2) Applicants must comply with the provision of paragraphs (c) or (d) of this section unless the application for modification demonstrates that, for each person predicted to receive new interference as a result of the change, existing predicted interference to two person will be eliminated. Persons predicted to receive new interference are those located outside the area predicted to receive interference from the station's currently authorized facilities (“existing predicted interference area”) but within the area predicted to receive interference from the proposed facilities (“proposed predicted interference area”). Persons for whom predicted interference will be eliminated are those located within the existing predicted interference area and outside the proposed predicted interference area.

(i) In making this calculation, the provisions contained at paragraph (e) will be used except as modified by paragraph (b)(3) of this section.

(ii) The following adjustment to the population calculation may be made: up to 1,000 persons may be subtracted from the population predicted to receive new interference if, for each person substracted, the applicant effectively installs two filters within 90 days after commencing program tests with the proposed facilities and, no later than 45 days thereafter, provides the affected TV Channel 6 station (as defined in paragraph (a) of this section) with a certification containing sufficient information to permit verification of such installation. The required number of filters will be installed on television receivers located within the predicted interference area; provided that half of the installations are within the area predicted to receive new interference.

(3) Where an NCE-FM applicant wishes to operate with facilities in excess of that permitted under the provisions of paragraphs (c) or (d) of this section, by proposing to use vertically polarized transmissions only, or to increase its ratio of vertically to horizontally polarized transmissions, the affected TV Channel 6 station must be given an option to pay for the required antenna and, if it takes that option, the NCE-FM vertically polarized component of power will be one half (−3 dB) that which would be allowed by the provisions of paragraph (e)(4) of this section.

(4) Applications for modification will include a certification that the applicant has given early written notice of the proposed modification to all affected TV Channel 6 stations (as defined in paragraph (a) of this section).

(5) Where the NCE-FM station demonstrates in its application that it must make an involuntary modification (e.g., due to loss of its transmitter site) that would not otherwise be permitted under this section, its application will be considered on a case-by-case basis. In such cases, the provisions of paragaph (b)(3) of this section do not apply.

(c) New NCE-FM stations. Except as provided for by paragraph (d) of this section, applicants for NCE-FM stations proposing to operate on Channels 201–220 must submit a showing indicating that the predicted interference area resulting from the proposed facility contains no more than 3,000 persons.

(1) In making these calculations, the provisions in paragraph (e) of this section will be used.

(2) The following adjustment to population may be made: up to 1,000 persons may be subtracted from the population within the predicted interference area if, for each person subtracted, the applicant effectively installs one filter within 90 days after commencing program tests and, no later than 45 days thereafter, provides the affected TV Channel 6 station with a certification containing sufficient information to permit verification of such installation. The required number of filters will be installed on television receivers located within the predicted interference area.

(d) Collocated Stations. As an alternative to the provisions contained in paragraphs (b) and (c) of this section, an application for a NCE-FM station operating on Channels 201–220 and located at 0.4 kilometer (approximately 0.25 mile) or less from a TV Channel 6 station will be accepted under the following requirements:

(1) The effective radiated power cannot exceed the following values:

(2) The NCE-FM application will include a certification that the applicant has coordinated its antenna with the affected TV station by employing either: The same number of antenna bays with radiation centers separated by no more than 30 meters (approximately 100 feet) verticially; or, the FM vertical pattern not exceeding the TV vertical pattern by more than 2dB.

(e) Calculation of predicted interference area and population. Predictions of interference required under this section and calculations to determine the number of persons within a predicted interference area for NCE-FM operation on Channels 201–220 are made as follows:

(1) The predicted interference area will be calculated as follows:

(i) The distances to the TV Channel 6 field strength contours will be predicted according to the procedures specified in §73.684, “Prediction of coverage,” using the F(50,50) curves in Figure 9, §73.699.

(ii) For each TV Channel 6 field strength contour, there will be an associated F(50,10) FM interference contour, the value of which (in units of dBu) is defined as the sum of the TV Channel 6 field strength (in dBu) and the appropriate undesired-to-desired (U/D) signal ratio (in dB) obtained from Figures 1 and 2, §73.599, corresponding to the channel of the NCE-FM applicant and the appropriate F(50,50) field strength contour of the TV Channel 6 station.

(iii) An adjustment of 6 dB for television receiving antenna directivity will be added to each NCE-FM interference contour at all points outside the Grade A field strength contour (§73.683) of the TV Channel 6 station and within an arc defined by the range of angles, of which the FM transmitter site is the vertex, from 110° relative to the azimuth from the FM transmitter site to the TV Channel 6 transmitter site, counterclockwise to 250° relative to that azimuth. At all points at and within the Grade A field strength contour of the TV Channel 6 station, the 6 dB adjustment is applicable over the range of angles from 70° clockwise to 110° and from 250° clockwise to 290°.

(iv) The distances to the applicable NCE-FM interference contours will be predicted according to the procedures specified in §73.313, “Prediction of Coverage,” using the proposed antenna height and horizontally polarized, or the horizontal equivalent of the vertically polarized, effective radiated power in the pertinent direction and the F(50,10) field strength curves (Figure 1a, §73.333).

(v) The predicted interference area will be defined as the area within the TV Channel 6 station's 47 dBu field strength contour that is bounded by the locus of intersections of a series of TV Channel 6 field strength contours and the applicable NCE-FM interference contours.

(vi) In cases where the terrain in one or more directions departs widely from the surrounding terrain average (for example, an intervening mountain), a supplemental showing may be made. Such supplemental showings must describe the procedure used and should include sample calculations. The application must also include maps indicating the predicted interference area for both the regular method and the supplemental method.

(vii) In cases where the predicted interference area to Channel 6 television from a noncommercial educational FM station will be located within the 90 dBu F(50,50) contour of the television Channel 6 station, the location of the FM interfering contour must be determined using the assumption that the Channel 6 field strength remains constant at 90 dBu everywhere within the 90 dBu TV contour. The FM to Channel 6 U/D signal strength ratio specified in §73.599 corresponding to the Channel 6 TV field strength of 90 dBu shall be used.

(2) The number of persons contained within the predicted interference area will be based on data contained in the most recently published U.S. Census of Population and will be determined by plotting the predicted interference area on a County Subdivision Map of the state published for the Census, and totalling the number of persons in each County Subdivision (such as, Minor Civil Division (MCD), Census County Division (CCD), or equivalent areas) contained within the predicted interference area. Where only a portion of County Subdivision is contained within the interference area:

(i) The population of all incorporated places or Census designated places will be subtracted from the County Subdivision population;

(ii) Uniform distribution of the remaining population over the remaining area of the County Subdivision will be assumed in determining the number of persons within the predicted interference area in proportion to the share of the remaining area of the County Subdivision that lies within the predicted interference area; and,

(iii) The population of the incorporated places or Census designated places contained within the predicted interference area will then be added to the total, again assuming uniform distribution of the population within the area of each place and adding a share of the population proportional to the share of the area if only a portion of such a place is within the predicted interference area.

(iv) At the option of either the NCE-FM applicant or an affected TV Channel 6 station which provides the appropriate analysis, more detailed population data may be used.

(3) Adjustments to the population calculated pursuant to paragraph (e)(2) of this section may be made as follows:

(i) If any part of the predicted interference area is within the Grade A field strength contour (§73.683) of a TV translator station carrying the affected TV Channel 6 station, the number of persons within that overlap area will be subtracted, provided the NCE-FM construction permit and license will contain the following conditions:

(A) When the TV translator station ceases to carry the affected TV Channel 6 station's service and the cessation is not the choice of the affected TV Channel 6 station, the NCE-FM station will modify its facilities, within a reasonable transition period, to meet the requirements of this section which would have applied if no adjustment to population for translator service had been made in its application.

(B) The transition period may not exceed 1 year from the date the NCE-FM station is notified by the TV Channel 6 station that the translator station will cease to carry the affected TV Channel 6 station's service or 6 months after the translator station ceases to carry the affected TV Channel 6 station's service, whichever is earlier.

(ii) If any part of the interference area is within the Grade B field strength contour (§73.683) of a satellite station of the affected TV Channel 6 station, the number of persons within the overlap area will be subtracted, provided the NCE-FM permit and license will contain the following conditions:

(A) If the satellite station ceases to carry the affected TV Channel 6 station's service and the cessation is not the choice of the affected TV Channel 6 station, the NCE-FM station will modify its facilities, within a reasonable transition period, to meet the requirements of this rule which would have applied if no adjustment to population for satellite station service had been made in its application.

(B) The transition period may not exceed 1 year from the date the NCE-FM station is notified by the TV Channel 6 station that the satellite station will cease to carry the affected TV Channel 6 stations's service or 6 months after the satellite station ceases to carry the affected TV Channel 6 station's service, whichever is earlier.

(iii) If any part of the predicted interference area is located outside the affected TV Channel 6 station's Area of Dominant Influence (ADI), outside the Grade A field strength contour (§73.683), and within the predicted city grade field strength contour (73.685(a)) of a TV broadcast station whose only network affiliation is the same as the only network affiliation of the affected TV Channel 6 station, the number of persons within that part will be subtracted. (For purposes of this provision, a network is defined as ABC, CBS, NBC, or their successors.) In addition, the ADI of an affected TV Channel 6 station and the program network affiliations of all relevant TV broadcast stations will be assumed to be as they were on the filing date of the NCE-FM application or June 1, 1985, whichever is later.

(iv) In calculating the population within the predicted interference area, an exception will be permitted upon a showing (e.g., as survey of actual television reception) that the number of persons within the predicted interference area should be reduced to account for persons actually experiencing co-channel or adjacent channel interference to reception of the affected TV Channel 6 station. The area within which such a showing may be made will be limited to the area calculated as follows:

(A) The distances to the field strength contours of the affected TV Channel 6 station will be predicted according to the procedures specified in §73.684, “Prediction of coverage,” using the F(50,50) curves in Figure 9, §73.699.

(B) For each field strength contour of the affected TV Channel 6 station, there will be an associated co-channel or adjacent channel TV broadcast station interference contour, the value of which (in units of dBu) is defined as the sum of the affected TV Channel 6 station's field strength (in dBu) and the appropriate undesired-to-desired signal ratio (in dB) as follows:

Co-channel, normal offset, −22 dB

(C) The distances to the associated co-channel or adjacent channel TV broadcast station interference contour will be predicted according to the procedures specified in §73.684, “Prediction of coverage,” using the F(50,10) curves in Figure 9a, §73.699.

(D) The area within which the showing of actual interference may be made will be the area bounded by the locus of intersections of a series of the affected TV Channel 6 station's field strength contours and the associated interference contours of the co-channel or adjacent channel TV broadcast station.

(4) The maximum permissible effective radiated power (ERP) and antenna height may be adjusted for vertical polarity as follows:

(i) If the applicant chooses to use vertically polarized transmissions only, the maximum permissible vertically polarized ERP will be the maximum horizontally polarized ERP permissible at the same proposed antenna height, calculated without the adjustment for television receiving antenna directivity specified in paragraph (e)(1)(iii) of this section, multiplied by either: 40 if the predicted interference area lies entirely outside the limits of a city of 50,000 persons or more; or 10 if it does not.

(ii) If the applicant chooses to use mixed polarity, the permissible ERP is as follows:

[H+(V/A)] is no greater than P

Where:

(f) Channel 200 Applications. No application for use of NCE-FM Channel 200 will be accepted if the requested facility would cause objectionable interference to TV Channel 6 operations. Such objectionable interference will be considered to exist whenever the 15 dBu contour based on the F(50,10) curves in §73.333 Figure 1a would overlap the 40 dBu contour based on the F(50,50) curves in §73.699, Figure 9.

[50 FR 27963, July 9, 1985; 50 FR 30187, July 24, 1985; 50 FR 31379, Aug. 2, 1985, as amended at 51 FR 26250, July 22, 1986; 52 FR 25867, July 9, 1987; 62 FR 51059, Sept. 30, 1997]

The requirements for indicating instruments described in §73.258 are applicable to all educational FM broadcast stations licensed with a transmitter power greater than 0.01 kw.

[51 FR 17029, May 8, 1986]

(a) All noncommercial educational FM stations will be licensed for unlimited time operation except those stations operating under a time sharing arrangement. All noncommercial educational FM stations are required to operate at least 36 hours per week, consisting of at least 5 hours of operation per day on at least 6 days of the week; however, stations licensed to educational institutions are not required to operate on Saturday or Sunday or to observe the minimum operating requirements during those days designated on the official school calendar as vacation or recess periods.

(b) All stations, including those meeting the requirements of paragraph (a) of this section, but which do not operate 12 hours per day each day of the year, will be required to share use of the frequency upon the grant of an appropriate application proposing such share time arrangement. Such applications shall set forth the intent to share time and shall be filed in the same manner as are applications for new stations. They may be filed at any time, but in cases where the parties are unable to agree on time sharing, action on the application will be taken only in connection with the renewal of application for the existing station. In order to be considered for this purpose, such an application to share time must be filed no later than the deadline for filing petitions to deny the renewal application of the existing licensee, or, in the case of renewal applications filed by the existing licensee on or before May 1, 1995, no later than the deadline for filing applications in conflict with the such renewal applications.

(1) The licensee and the prospective licensee(s) shall endeavor to reach an agreement for a definite schedule of periods of time to be used by each. Such agreement shall be in writing and shall set forth which licensee is to operate on each of the hours of the day throughout the year. Such agreement shall not include simultaneous operation of the stations. Each licensee shall file the same in triplicate with each application to the Commission for initial construction permit or renewal of license. Such written agreements shall become part of the terms of each station's license.

(2) The Commission desires to facilitate the reaching of agreements on time sharing. However, if the licensees of stations authorized to share time are unable to agree on a division of time, the Commission shall be so notified by statement to that effect filed with the application proposing time sharing. Thereafter the Commission will designate the application for hearing on any qualification issues arising regarding the renewal or new applicants. If no such issues pertain, the Commission will set the matter for expedited hearing limited solely to the issue of the sharing of time. In the event the stations have been operating under a time sharing agreement but cannot agree on its continuation, a hearing will be held, and pending such hearing, the operating schedule previously adhered to shall remain in full force and effect.

(c) A departure from the regular schedule set forth in a time-sharing agreement will be permitted only in cases where a written agreement to that effect is reduced to writing, is signed by the licensees of the stations affected thereby, and is filed in triplicate by each licensee with the Commission, Attention: Audio Division, Media Bureau, prior to the time of the proposed change. If time is of the essence, the actual departure in operating schedule may precede the actual filing of the written agreement, provided that appropriate notice is sent to the Commission in Washington, DC, Attention: Audio Division, Media Bureau.

(d) In the event that causes beyond the control of a permittee or licensee make it impossible to adhere to the operating schedule in paragraph (a) or (b) of this section or to continue operating, the station may limit or discontinue operation for a period not exceeding 30 days without further authority from the Commission provided that notification is sent to the Commission in Washington, DC, Attention: Audio Division, Media Bureau, no later than the 10th day of limited or discontinued operation. During such period, the permittee shall continue to adhere to the requirements of the station license pertaining to the lighting of antenna structures. In the event normal operation is restored prior to the expiration of the 30 day period, the permittee or licensee will notify the FCC, Attention: Audio Division of the date that normal operations resumed. If causes beyond the control of the permittee or licensee make it impossible to comply within the allowed period, Special Temporary Authority (see §73.1635) must be requested to remain silent for such additional time as deemed necessary. The license of a broadcasting station that fails to transmit broadcast signals for any consecutive 12 month period expires as a matter of law at the end of that period, notwithstanding any provision, term, or condition of license to the contrary.

Note 1 to §73.561: For allocations purposes, both (all) stations sharing time will be treated as unlimited time stations.

Note 2 to §73.561: See §§73.1705, 73.1715, and 73.1740.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[43 FR 39717, Sept. 6, 1978, as amended at 43 FR 45845, Oct. 4, 1978; 44 FR 3416, Jan. 19, 1979; 44 FR 65764, Nov. 15, 1979; 47 FR 54448, Dec. 3, 1982; 50 FR 13974, Apr. 9, 1985; 61 FR 18291, Apr. 25, 1996; 61 FR 28767, June 6, 1996; 63 FR 33877, June 22, 1998; 67 FR 13231, Mar. 21, 2002]

The procedures for determining operating power described in §73.267 are applicable to noncommercial education FM stations.

[44 FR 58732, Oct. 11, 1979]

The licensee of a noncommercial educational FM station is not required to use its subcarrier capacity, but if it chooses to do so, it is governed by §§73.293 through 73.295 of the Commission's Rules regarding the types of permissible subcarrier uses and the manner in which subcarrier operations shall be conducted; Provided, however, that remunerative use of a station's subcarrier capacity shall not be detrimental to the provision of existing or potential radio reading services for the blind or otherwise inconsistent with its public broadcasting responsibilities.

[48 FR 26615, June 9, 1983]

A noncommercial educational FM broadcast station may, without specific authority from the FCC, transmit stereophonic sound programs upon installation of stereophonic sound transmitting equipment under the provisions of §§2.977, 2.1001, 73.322, and 73.1590 of the FCC's Rules.

[51 FR 17029, May 8, 1986]

This section consists of the following Figures 1 and 2.

[50 FR 27965, July 9, 1985]

This subpart contains the rules and regulations (including engineering standards) governing TV broadcast stations, including noncommercial educational TV broadcast stations and, where indicated, low power TV and TV translator stations in the United States, its Territories and possessions. TV broadcast, low power TV, and TV translator stations are assigned channels 6 MHz wide, designated as set forth in §73.603(a).

[47 FR 21494, May 18, 1982]

See §73.1010.

[43 FR 32781, July 28, 1978]

(a)

(b) [Reserved]

(c) Channel 37, 608–614 MHz is reserved exclusively for the radio astronomy service.

(d) In Hawaii, the frequency band 488–494 MHz is allocated for non-broadcast use. This frequency band (Channel 17) will not be assigned in Hawaii for use by television broadcast stations.

[28 FR 13660, Dec. 14, 1963, as amended at 35 FR 11179, July 11, 1970; 39 FR 10576, Mar. 21, 1974; 47 FR 16789, Apr. 20, 1982; 47 FR 30068, July 12, 1982; 47 FR 35989, Aug. 18, 1982; 51 FR 18450, May 20, 1986; 70 FR 46676, Aug. 10, 2005]

(a) General. The following table of allotments contains the channels designated for the listed communities in the United States, its Territories, and possessions. Channels designated with an asterisk are assigned for use by noncommercial educational broadcast stations only. A station on a channel identified by a plus or minus mark is required to operate with its carrier frequencies offset 10 kHz above or below, respectively, the nominal carrier frequencies.

(b) Table of Allotments.

(Sec. 5, 48 Stat. 1068; 47 U.S.C. 155)

[28 FR 13660, Dec. 14, 1963]

Editorial Note:  For Federal Register citations affecting §73.606, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO Access.

§ 73.607   Availability of channels.

(a) Applications may be filed to construct TV broadcast stations only on the channels designated in the Table of Allotments (§73.606(b)) and only in the communities listed therein. Applications which fail to comply with this requirement, whether or not accompanied by a petition to amend the Table, will not be accepted for filing. However, applications specifying channels which accord with publicly announced FCC Orders changing the Table of Allotments will be accepted for filing even though such applications are tendered before the effective dates of such channel changes.

(b) Notwithstanding paragraph (a) of this section, an application may be filed for a channel or community not listed in the TV Table of Allotments if it is consistent with the rules and policies established in the Third Report and Order in WT Docket 99–168 (FCC 01–25), adopted January 18, 2001. Where such a request is approved, the Media Bureau will change the Table of Allotments to reflect that approval.

[51 FR 44070, Dec. 8, 1986, as amended at 66 FR 10208, Feb. 14, 2001; 67 FR 13232, Mar. 21, 2002]

(a) For the purpose of allotment and assignment, the United States is divided into three zones as follows:

(1) Zone I consists of that portion of the United States located within the confines of the following lines drawn on the U.S. Albers Equal Area Projection Map (based on standard parallels 291/2° and 451/2°; North American datum): Beginning at the most easterly point on the State boundary line between North Carolina and Virginia; thence in a straight line to a point on the Virginia-West Virginia boundary line located at north latitude 37°49' and west longitude 80°12'30"; thence westerly along the southern boundary lines of the States of West Virginia, Ohio, Indiana, and Illinois to a point at the junction of the Illinois, Kentucky, and Missouri State boundary lines; thence northerly along the western boundary line of the State of Illinois to a point at the junction of the Illinois, Iowa, and Wisconsin State boundary lines; thence easterly along the northern State boundary line of Illinois to the 90th meridian; thence north along this meridian to the 43.5° parallel; thence east along this parallel to the United States-Canada border; thence southerly and following that border until it again intersects the 43.5° parallel; thence east along this parallel to the 71st meridian; thence in a straight line to the intersection of the 69th meridian and the 45th parallel; thence east along the 45th parallel to the Atlantic Ocean. When any of the above lines pass through a city, the city shall be considered to be located in Zone I. (See Figure 1 of §73.699.)

(2) Zone II consists of that portion of the United States which is not located in either Zone I or Zone III, and Puerto Rico, Alaska, Hawaiian Islands and the Virgin Islands.

(3) Zone III consists of that portion of the United States located south of a line, drawn on the United States Albers Equal Area Projection Map (based on standard parallels 29.50 and 45.50 North American datum), beginning at a point on the east coast of Georgia and the 31st parallel and ending at the United States-Mexican border, consisting of arcs drawn with a 241.4 kilometer (150 mile) radius to the north from the following specified points:

When any of the above arcs pass through a city, the city shall be considered to be located in Zone II. (See Figure 2 of §73.699.)

[28 FR 13660, Dec. 14, 1963, as amended at 33 FR 15422, Oct. 17, 1968; 50 FR 23697, June 5, 1985; 51 FR 44070, Dec. 8, 1986]

(a) The provisions of this section relate to allotment separations and station separations. Petitions to amend the Table of Allotments (§73.606(b)) (other than those also expressly requesting amendment of this section or §73.609) will be dismissed and all applications for new TV broadcast stations or for changes in the transmitter sites of existing stations will not be accepted for filing if they fail to comply with the requirements specified in paragraphs (b), (c) and (d) of this section.

Note: Licensees and permittees of television broadcast stations which were operating on April 14, 1952 pursuant to one or more separations below those set forth in §73.610 may continue to so operate, but in no event may they further reduce the separations below the minimum. As the existing separations of such stations are increased, the new separations will become the required minimum separations until separations are reached which comply with the requirements of §73.610. Thereafter, the provisions of said section shall be applicable.

(b) Minimum co-channel allotment and station separations:

(1)

(2) The minimum co-channel distance separation between a station in one zone and a station in another zone shall be that of the zone requiring the lower separation.

(c) Minimum allotment and station adjacent channel separations applicable to all zones:

(1) Channels 2–13 95.7 kilometers (59.5 miles). Channels 14–69 87.7 kilometers (54.5 miles).

(2) Due to the frequency spacing which exists between Channels 4 and 5, between Channels 6 and 7, and between Channels 13 and 14, the minimum adjacent channel separations specified above shall not be applicable to these pairs of channels (see §73.603(a)).

(d) In addition to the requirements of paragraphs (a), (b) and (c) of this section, the minimum assignment and station separations between stations on Channels 14–69, inclusive, as set forth in Table II of §73.698 must be met in either rule-making proceedings looking towards the amendment of the Table of Assignments (§73.606(b)) or in licensing proceedings. No channel listed in column (1) of Table II of §73.698 will be assigned to any city, and no application for an authorization to operate on such a channel will be granted, unless the distance separations indicated at the top of columns (2) through (7), inclusive, are met with respect to each of the channels listed in those columns and parallel with the channel in column (1).

(e) The zone in which the transmitter of a television station is located or proposed to be located determines the applicable rules with respect to co-channel distance separations where the transmitter is located in a different zone from that in which the channel to be employed is located.

(f) The distances listed below apply only to allotments and assignments on Channel 6 (82–88 MHz). The Commission will not accept petitions to amend the Table of Allotments, applications for new stations, or applications to change the channel or location of existing assignments where the following minimum distances (between transmitter sites, in kilometers) from any FM Channel 253 allotment or assignment are not met:

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13660, Dec. 14, 1963, as amended at 37 FR 25842, Dec. 5, 1972; 44 FR 65765, Nov. 15, 1979; 47 FR 35990, Aug. 18, 1982; 50 FR 23698, June 5, 1985; 51 FR 44070, Dec. 8, 1986; 54 FR 14964, Apr. 14, 1989; 54 FR 16368, Apr. 24, 1989; 54 FR 35340, Aug. 25, 1989]

(a) In considering petitions to amend the Table of Allotments (§73.606(b)), the following reference points shall be used by the Commission in determining assignment separations between communities:

(1) Where transmitter sites for the pertinent channels have been authorized in communities involved in a petition to amend the Table of Allotments, separations between such communities shall be determined by the distance between the coordinates of the authorized transmitter sites in the respective communities as set forth in the Commission's authorizations therefor.

(2) Where an authorized transmitter site is available for use as a reference point in one community but not in the other for the pertinent channels, separations shall be determined by the distance between the coordinates of the transmitter site as set forth in the FCC's authorization therefor and the coordinates of the other community as set forth in the publication of the United States Department of the Interior entitled, Index to The National Atlas of the United States of America. If this publication does not contain the coordinates for said other community, the coordinates of the main post office thereof shall be used.

(3) Where no authorized transmitter sites are available for use as reference points in both communities for the pertinent channels, the distance between the two communities listed in the above publication shall be used. If said publication does not contain such distance, the separation between the two communities shall be determined by the distance between the coordinates thereof as set forth in the publication. Where such coordinates are not contained in the publication, the coordinates of the main post offices of said communities shall be used.

(4) Where the distance between the reference point in a community to which a channel is proposed to be assigned and the reference point in another community or communities does not meet the minimum separation requirements of §73.610, the channel may be assigned to such community upon a showing that a transmitter site is available that would meet the minimum separation requirements of §73.610 and the minimum field strength requirements of §73.685. In such cases, where a station is not authorized in the community or communities to which measurements from the proposed channel assignment must be made pursuant to §73.610 a showing should also be made that the distance between suitable transmitter sites in such other community or communities and the proposed transmitter site for the new channel meet the Commission's minimum spacing and coverage requirements.

(b) Station separations in licensing proceedings shall be determined by the distance between the coordinates of the proposed transmitter site in one community and

(1) The coordinates of an authorized transmitter site for the pertinent channel in the other community; or, where such transmitter site is not available for use as a reference point,

(2) The coordinates of the other community as set forth in the Index to The National Atlas of the United States of America; or if not contained therein,

(3) The coordinates of the main post office of such other community.

(4) In addition, where there are pending applications in other communities which, if granted, would have to be considered in determining station separations, the coordinates of the transmitter sites proposed in such applications must be used to determine whether the requirements with respect to minimum separations between the proposed stations in the respective cities have been met.

(c) In measuring assignment and station separations involving cities listed in the Table in combination, where there is no authorized transmitter site in any of the combination cities on the channel involved, separation measurements shall be made from the reference point which will result in the lowest separation.

(d) To calculate the distance between two reference points see paragraph (c), §73.208. However, distances shall be rounded to the nearest tenth of a kilometer.

[52 FR 11655, Apr. 10, 1987]

(a) Permittees and licensees of TV broadcast stations are not protected from any interference which may be caused by the grant of a new station or of authority to modify the facilities of an existing station in accordance with the provisions of this subpart. The nature and extent of the protection from interference accorded to TV broadcast stations is limited solely to the protection which results from the minimum allotment and station separation requirements and the rules and regulations with respect to maximum powers and antenna heights set forth in this subpart.

(b) When the Commission determines that grant of an application would serve the public interest, convenience, and necessity and the instrument of authorization specifies an antenna location in a designated antenna farm area which results in distance separation less than those specified in this subpart, TV broadcast station permittees and licensees shall be afforded protection from interference equivalent to the protection afforded under the minimum distance separations specified in this subpart.

Note: The nature and extent of the protection from interference accorded to TV broadcast stations which were authorized prior to April 14, 1952, and which were operating on said date is limited not only as specified above but is further limited by any smaller separations existing between such stations on said date. Where, as a result of the adoption of the Table of Allotments or of changes in transmitter sites made by such stations after said date, separations smaller than the required minimum are increased but still remain lower than the required minimum, protection accorded such stations will be limited to the new separations.

[28 FR 13660, Dec. 14, 1963, as amended at 32 FR 8814, June 21, 1967; 50 FR 23698, June 5, 1985; 51 FR 44070, Dec. 8, 1986]

(a) An application for a new TV broadcast station or for changes in the operating facilities of an existing TV broadcast station will not be accepted for filing if it fails to comply with the requirements specified in this section.

Note to §73.613(a): Licensees and permittees of TV broadcast stations that were authorized on November 29, 1999 (and applicants for new TV stations that had been cut-off without competing applications or that were the winning bidder in a TV broadcast station auction as of that date, or that were the proposed remaining applicant in a group of mutually exclusive applications for which a settlement agreement was on file as of that date) may continue to operate with facilities that do not protect Class A TV stations. Applications filed on or before November 29, 1999 for a change in the operating facilities of such stations also are not required to protect Class A TV stations under the provisions of this section.

(b) Due to the frequency spacing which exists between TV channels 4 and 5, between channels 6 and 7, and between channels 13 and 14, first-adjacent channel protection standards shall not be applicable to these pairs of channels. Some interference protection requirements of this section only apply to stations transmitting on the UHF TV channels 14 through 51 (See §73.603(a) of this part).

(c) A UHF TV broadcast station application will not be accepted if it specifies a site less than 100 kilometers from the transmitter site of a UHF Class A TV station operating on a channel which is the seventh channel above the requested channel. Compliance with this requirement shall be determined based on a distance computation rounded to the nearest kilometer.

(d) A UHF TV broadcast station application will not be accepted if it specifies a site less than 32 kilometers from the transmitter site of a UHF Class A TV station that is authorized an effective radiated power of more than 50 kilowatts and operating on a channel which is the second, third, or fourth channel above or below the requested channel. Compliance with this requirement shall be determined based on a distance computation rounded to the nearest kilometer.

(e) In cases where a TV broadcast station has been authorized facilities that do not meet the distance separation requirements of this section, an application to modify such a station's facilities will not be accepted if it decreases that separation.

(f) New interference must not be caused to Class A TV stations authorized pursuant to Subpart J of this part, within the protected contour defined in §73.6010 of this part. For this prediction, the TV broadcast station field strength is calculated from the proposed effective radiated power and the antenna height above average terrain in pertinent directions using the methods in §73.684 of this part.

(1) For co-channel protection, the field strength is calculated using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699 of this part.

(2) For TV broadcast stations that do not specify the same channel as the Class A TV station to be protected, the field strength is calculated using the appropriate F(50,50) chart from Figure 9, 10, or 10b of §73.699 of this part.

(g) A TV broadcast station application will not be accepted if the ratio in dB of its field strength to that of the Class A TV station at the Class A TV station's protected contour fails to meet the following:

(1) −45 dB for co-channel operations where the Class A TV station does not specify an offset carrier frequency or where the TV broadcast and Class A TV stations do not specify different offset carrier frequencies (zero, plus or minus) or −28 dB for offset carrier frequency operation where the TV broadcast and Class A TV stations specify different offset carrier frequencies.

(2) 6 dB when the protected Class A TV station operates on a VHF channel that is one channel above the requested channel.

(3) 12 dB when the protected Class A TV station operates on a VHF channel that is one channel below the requested channel.

(4) 15 dB when the protected Class A TV station operates on a UHF channel that is one channel above or below the requested channel.

(5) 23 dB when the protected Class A TV station operates on a UHF channel that is fourteen channels below the requested channel.

(6) 6 dB when the protected Class A TV station operates on a UHF channel that is fifteen channels below the requested channel.

(h) New interference must not be caused to digital Class A TV stations authorized pursuant to Subpart J of this part, within the protected contour defined in §73.6010 of this part. A TV broadcast station application will not be accepted if the ratio in dB of the field strength of the digital Class A TV station at the digital Class A TV station's protected contour to the field strength resulting from the facilities proposed in the TV broadcast station application fails to meet the D/U signal ratios for “analog TV-into-DTV” specified in §§73.623(c)(2) and 73.623(c)(3) of this part. For digital Class A TV station protection, the TV broadcast station field strength is calculated from the proposed effective radiated power and the antenna height above average terrain in pertinent directions using the methods in §73.684 of this part and using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699 of this part.

(i) In cases where a TV broadcast station has been authorized facilities that do not meet the interference protection requirements of this section, an application to modify such a station's facilities will not be accepted if it is predicted to cause new interference within the protected contour of the Class A TV or digital Class A TV station.

(j) In support of a request for waiver of the interference protection requirements of this section, an applicant for a TV broadcast station may make full use of terrain shielding and Longley-Rice terrain dependent propagation methods to demonstrate that the proposed facility would not be likely to cause interference to Class A TV stations. Guidance on using the Longely-Rice methodology is provided in OET Bulletin No. 69, which is available through the Internet at http://www.fcc.gov/oet/info/documents/bulletins/#69.

[65 FR 3001, May 10, 2000]

(a) Minimum requirements. Applications will not be accepted for filing if they specify less than −10 dBk (100 watts) horizontally polarized visual effective radiated power in any horizontal direction. No minimum antenna height above average terrain is specified.

(b) Maximum power. Applications will not be accepted for filing if they specify a power which exceeds the maximum permitted boundaries specified in the following formulas:

(1) Channels 2–6 in Zone I:

ERP_Max=102.57–33.24*Log₁₀(HAAT)

And,

−10 dBk ≤ ERP_Max≤20 dBk

(2) Channels 2–6 in Zones II and III:

ERP_Max=67.57–17.08* Log₁₀ (HAAT)

And,

10 dBk ≤ ERP_Max≤20 dBk

(3) Channels 7–13 in Zone I:

ERP_Max=107.57–33.24* Log₁₀ (HAAT)

And,

−4.0 dBk ≤ ERP_Max ≤25 dBk

(4) Channels 7–13 in Zones II and III:

ERP_Max=72.57–17.08* Log₁₀ (HAAT)

And,

15 dBk ≤ ERP_Max≤25 dBk

(5) Channels 14–69 in Zones I, II, and III:

ERP_Max=84.57–17.08* Log₁₀ (HAAT)

And,

27 dBk ≤ ERP_Max≤37 dBk

Where:

The boundaries specified are to be used to determine the maximum possible combination of antenna height and   ERP_dBk. When specifying an ERP_dBk less than that permitted by the lower boundary, any antenna HAAT can be used. Also, for values of antenna HAAT greater than 2,300 meters the maximum ERP is the lower limit specified for each equation.

(6) The effective radiated power in any horizontal or vertical direction may not exceed the maximum values permitted by this section.

(7) The effective radiated power at any angle above the horizontal shall be as low as the state of the art permits, and in the same vertical plane may not exceed the effective radiated power in either the horizontal direction or below the horizontal, whichever is greater.

(c) Determination of applicable rules. The zone in which the transmitter of a television station is located or proposed to be located determines the applicable rules with respect to maximum antenna heights and powers for VHF stations when the transmitter is located in Zone I and the channel to be employed is located in Zone II, or the transmitter is located in Zone II and the channel to be employed is located in Zone I.

[28 FR 13660, Dec. 14, 1963, as amended at 42 FR 20823, Apr. 22, 1977; 42 FR 48881, Sept. 26, 1977; 47 FR 35990, Aug. 18, 1982; 50 FR 23698, June 5, 1985; 56 FR 49707, Oct. 1, 1991; 58 FR 51250, Oct. 1, 1993]

In the issuance of television broadcast station authorizations, the Commission will specify the transmitter output power and effective radiated power to the nearest 0.1 dBk. Power specified by kWs shall be obtained by converting dBk to kWs to 3 significant figures. Antenna heights above average terrain will be specified to the nearest meter. Midway figures will be authorized in the lower alternative.

[50 FR 23698, June 5, 1985]

In addition to the other provisions of this subpart, the following shall be applicable to noncommercial educational television broadcast stations:

(a) Except as provided in paragraph (b) of this section, noncommercial educational broadcast stations will be licensed only to nonprofit educational organizations upon a showing that the proposed stations will be used primarily to serve the educational needs of the community; for the advancement of educational programs; and to furnish a nonprofit and noncommercial television broadcast service.

(1) In determining the eligibility of publicly supported educational organizations, the accreditation of their respective state departments of education shall be taken into consideration.

(2) In determining the eligibility of privately controlled educational organizations, the accreditation of state departments of education or recognized regional and national educational accrediting organizations shall be taken into consideration.

(b) Where a municipality or other political subdivision has no independently constituted educational organization such as, for example, a board of education having autonomy with respect to carrying out the municipality's educational program, such municipality shall be eligible for a noncommercial educational television broadcast station. In such circumstances, a full and detailed showing must be made that a grant of the application will be consistent with the intent and purpose of the Commission's rules and regulations relating to such stations.

(c) Noncommercial educational television broadcast stations may transmit educational, cultural and entertainment programs, and programs designed for use by schools and school systems in connection with regular school courses, as well as routine and administrative material pertaining thereto.

(d) A noncommercial educational television station may broadcast programs produced by or at the expense of, or furnished by persons other than the licensee, if no other consideration than the furnishing of the program and the costs incidental to its production and broadcast are received by the licensee. The payment of line charges by another station, network, or someone other than the licensee of a noncommercial educational television station, or general contributions to the operating costs of a station, shall not be considered as being prohibited by this paragraph.

(e) Each station shall furnish a nonprofit and noncommercial broadcast service. Noncommercial educational television stations shall be subject to the provisions of §73.1212 to the extent that they are applicable to the broadcast of programs produced by, or at the expense of, or furnished by others. No promotional announcements on behalf of for profit entities shall be broadcast at any time in exchange for the receipt, in whole or in part, of consideration to the licensee, its principals, or employees. However, acknowledgements of contributions can be made. The scheduling of any announcements and acknowledgements may not interrupt regular programming.

Note: Commission interpretation of this rule, including the acceptable form of acknowledgements, may be found in the Second Report and Order in Docket No. 21136 (Commission Policy Concerning the Noncommercial Nature of Educational Broadcast Stations), 86 F.C.C. 2d 141 (1981); the Memorandum Opinion and Order in Docket No. 21136, 90 FCC 2d 895 (1982), and the Memorandum Opinion and Order in Docket 21136, 49 FR 13534, April 5, 1984.

(f) Telecommunications Service on the Vertical Blanking Interval and in the Visual Signal. The provisions governing VBI and visual signal telecommunications service in §73.646 are applicable to noncommercial educational TV stations.

(g) Non-program related data signals transmitted on Line 21 pursuant to §73.682(a)(22)(ii) may be used for remunerative purposes.

(h) Mutually exclusive applications for noncommercial educational TV stations operating on reserved channels shall be resolved pursuant to the point system in subpart K.

(i) With respect to the provision of advanced television services, the requirements of this section will apply to the entire digital bitstream of noncommercial educational television stations, including the provision of ancillary or supplementary services.

[28 FR 13660, Dec. 14, 1963, as amended at 35 FR 7558, May 15, 1970; 47 FR 36179, Aug. 19, 1982; 48 FR 27068, June 13, 1983; 49 FR 29069, July 18, 1984; 50 FR 4664, Feb. 1, 1985; 50 FR 4684, Feb. 1, 1985; 61 FR 36304, July 10, 1996; 65 FR 36378, June 8, 2000; 66 FR 58982, Nov. 26, 2001]

(a) General. The following table of allotments contains the digital television (DTV) channel allotments designated for the listed communities in the United States, its Territories, and possessions. The initial DTV Table of Allotments was established on April 3, 1997, to provide a second channel for DTV service for all eligible analog television broadcasters. Requests for addition of new DTV allotments, or requests to change the channels allotted to a community must be made in a petition for rule making to amend the DTV Table of Allotments. A request to amend the DTV table to change the channel of an allotment in the DTV table will be evaluated for technical acceptability using engineering criteria set forth in §73.623(c). A request to amend the DTV table to add a new allotment will be evaluated for technical acceptability using the geographic spacing criteria set forth in §73.623(d). DTV allotments designated with an asterisk are assigned for use by non-commercial educational broadcast stations only. Stations operating on DTV allotments designated with a “c” are required to comply with paragraph (g) of this section. Rules governing noncommercial educational TV stations are contained in §73.621. Where there is only one technically available channel available in a community, an entity that would be eligible to operate a noncommercial educational broadcast station may, prior to application, initiate a rulemaking proceeding requesting that an unoccupied or new channel in the community be changed or added as reserved only for noncommercial educational broadcasting upon demonstrating that the noncommercial educational proponent would provide a first or second noncommercial educational TV service to 2,000 or more people who constitute 10% of the population within the proposed allocation's noise limited contour.

(1) Petitions requesting the addition of a new allotment must specify a channel in the range of channels 2–51.

(2) Petitions requesting a change in the channel of an initial allotment must specify a channel in the range of channels 2–58.

(b) DTV Table of Allotments.

(c)(1) Availability of channels. Applications may be filed to construct DTV broadcast stations only on the channels designated in the DTV Table of Allotments set forth in paragraph (b) of this section, and only in the communities listed therein. Applications that fail to comply with this requirement, whether or not accompanied by a petition to amend the DTV Table, will not be accepted for filing. However, applications specifying channels that accord with publicly announced FCC Orders changing the DTV Table of Allotments will be accepted for filing even if such applications are tendered before the effective dates of such channel change. An application for authority to construct a DTV station on an allotment in the initial DTV table may only be filed by the licensee or permittee of the analog TV station with which that initial allotment is paired, as set forth in Appendix B of the Memorandum Opinion and Order on Reconsideration of the Sixth Report and Order in MM Docket 87–268, FCC 98–24 (Memorandum Opinion and Order) adopted January 29, 1998. Copies of the Memorandum Opinion and Order may be inspected during normal business hours at the: Federal Communications Commission, Room CY-C203, 445 12th Street, SW., Reference Information Center, Washington, DC, 20554. This document is also available through the Internet on the FCC Home Page at http://www.fcc.gov. Applications may also be filed to implement an exchange of channel allotments between two or more licensees or permittees of analog TV stations in the same community, the same market, or in adjacent markets provided, however, that the other requirements of this section and §73.623 are met with respect to each such application.

(2) Notwithstanding paragraph (c)(1) of this section, an application may be filed for a channel or community not listed in the DTV Table of Allotments if it is consistent with the rules and policies established in the Third Report and Order in WT Docket 99–168 (FCC 01–25), adopted January 18, 2001. Where such a request is approved, the Media Bureau will change the DTV Table of Allotments to reflect that approval.

(d) Reference points and distance computations. (1) The reference coordinates of a DTV allotment included in the initial DTV Table of Allotments are the coordinates of the authorized transmitting antenna site of the associated analog TV station, as set forth in Appendix B of the Memorandum Opinion and Order (referenced above). An application for authority to construct or modify DTV facilities on such an allotment may specify an alternate location for the DTV transmitting antenna that is within 5 kilometers of the DTV allotment reference coordinates without consideration of electromagnetic interference to other DTV or analog TV broadcast stations, allotments or applications, provided the application complies with paragraph (f)(2) of this section. Location of the transmitting antenna of such a station at a site more than 5 kilometers from the DTV allotment reference coordinates must comply with the provisions of section 73.623(c). In the case where a DTV station has been granted authority to construct more than 5 kilometers from its reference coordinates pursuant to section 73.623(c), and its authorized coverage area extends in any azimuthal direction beyond the DTV coverage area determined for the DTV allotment reference facilities, then the coordinates of such authorized site are to be used in addition to the coordinates of the DTV allotment to determine protection from new DTV allotments pursuant to §73.623(d) and from subsequent DTV applications filed pursuant to §73.623(c).

(2) The reference coordinates of a DTV allotment not included in the initial DTV Table of Allotments shall be the authorized transmitter site, or, where such a transmitter site is not available for use as a reference point, the coordinates as designated in the FCC order modifying the DTV Table of Allotments.

(e) DTV Service Areas. (1) The service area of a DTV station is the geographic area within the station's noise-limited F(50,90) contour where its signal strength is predicted to exceed the noise-limited service level. The noise-limited contour is the area in which the predicted F(50,90) field strength of the station's signal, in dB above 1 microvolt per meter (dBu) as determined using the method in section 73.625(b) exceeds the following levels (these are the levels at which reception of DTV service is limited by noise):

(2) Within this contour, service is considered available at locations where the station's signal strength, as predicted using the terrain dependent Longley-Rice point-to-point propagation model, exceeds the levels above. Guidance for evaluating coverage areas using the Longley-Rice methodology is provided in OET Bulletin No. 69. Copies of OET Bulletin No. 69 may be inspected during normal business hours at the Federal Communications Commission, 445 12th Street, S.W, Dockets Branch (Room CY A09257), Washington, DC 20554. This document is also available through the Internet on the FCC Home Page at http://www.fcc.gov.

Note to paragraph (e)(2): During the transition, in cases where the assigned power of a UHF DTV station in the initial DTV Table is 1000 kW, the Grade B contour of the associated analog television station, as authorized on April 3, 1997, shall be used instead of the noise-limited contour of the DTV station in determining the DTV station's service area. In such cases, the DTV service area is the geographic area within the station's analog Grade B contour where its DTV signal strength is predicted to exceed the noise-limited service level, i.e., 41 dB, as determined using the Longley-Rice methodology.

(3) For purposes of determining whether interference is caused to a DTV station's service area, the maximum technical facilities, i.e., antenna height above average terrain (antenna HAAT) and effective radiated power (ERP), specified for the station's allotment are to be used in determining its service area.

(f) DTV maximum power and antenna heights. (1) The maximum, or reference, effective radiated power (ERP) and antenna height above average terrain (antenna HAAT) for an allotment included in the initial DTV Table of Allotments are set forth in Appendix B of the Memorandum Opinion and Order (referenced in paragraph (c) of this section). In each azimuthal direction, the reference ERP value is based on the antenna HAAT of the corresponding analog TV station and achieving predicted coverage equal to that analog TV station's predicted Grade B contour, as defined in section 73.683.

(2) An application for authority to construct or modify DTV facilities will not be subject to further consideration of electromagnetic interference to other DTV or analog TV broadcast stations, allotments or applications, provided that:

(i) The proposed ERP in each azimuthal direction is equal to or less than the reference ERP in that direction; and

(ii) The proposed antenna HAAT is equal to or less than the reference antenna HAAT or the proposed antenna HAAT exceeds the reference antenna HAAT by 10 meters or less and the reference ERP in paragraph (f)(2)(i) of this section is adjusted in accordance with paragraph (f)(3) of this section; and

(iii) The application complies with the location provisions in paragraph (d)(1) of this section.

(3)(i) A DTV station may increase its antenna HAAT by up to 10 meters from that specified in Appendix B if it reduces its DTV power to a level at or below the level of adjusted DTV power computed in the following formula:

ERP adjustment in dB = 20log(H₁/H₂)

Where H₁ = Reference antenna HAAT specified in the DTV Table, and H₂ = Actual antenna HAAT

(ii) Alternatively, a DTV application that specifies an antenna HAAT within 25 meters below that specified in Appendix B may adjust its power upward to a level at or below the adjusted DTV power in accordance with the formula in paragraph (f)(3)(i) of this section without an interference showing. For a proposed antenna more than 25 meters below the reference antenna HAAT, the DTV station may increase its ERP up to the level permitted for operation with an antenna that is 25 meters below the station's reference antenna HAAT.

(4) UHF DTV stations may request an increase in power, up to a maximum of 1000 kW ERP, to enhance service within their authorized service area through use of antenna beam tilting in excess of 1 degree, as follows:

(i) Field strengths at the outer edge of the station's service area shall be no greater than the levels that would exist if the station were operating at its assigned DTV power.

(ii) Where a station operates at higher power under the provisions of this paragraph, its field strengths at the edge of its service area are to be calculated assuming 1 dB of additional antenna gain over the antenna gain pattern specified by the manufacturer.

(iii) Where a first adjacent channel DTV station or allotment is located closer than 110 km or a first adjacent channel analog TV station is located closer than 106 km from the proposed transmitter site, the application must be accompanied by a technical showing that the proposed operation complies with the technical criteria in §73.623(c) and thereby will not result in new interference exceeding the de minimis standard for new interference set forth in that section, or statements from affected stations agreeing to the proposed operation in accordance with §73.623(f).

(iv) A licensee desiring to operate at higher power under these provisions shall submit, with its initial application for a DTV construction permit or subsequent application to modify its DTV facilities, an engineering analysis demonstrating that the predicted field strengths and predicted interference within its service area would comport with the requirements of this paragraph. The licensee also must notify, by certified mail, all stations that could potentially be affected by such operation at the time the station files its application for a construction permit or modification of facilities. Potentially affected stations to be notified include stations on co-channel and first-adjacent channel allotments that are located at distances less than the minimum geographic spacing requirements in §73.623(d)(2). For example, in Zone I a co-channel DTV station within 196.3 km or a first-adjacent channel DTV station within 110 km must be notified. A station that believes that its service is being affected beyond the de minimis standard set forth in §73.623(c) may file an informal objection with the Commission. Such an informal objection shall include an engineering analysis demonstrating that additional impermissible interference would occur. The Commission may condition grant of authority to operate at increased power pursuant to this provision on validation of actual performance through field measurements.

(5) Licensees and permittees assigned a DTV channel in the initial DTV Table of Allotments may request an increase in either ERP in some azimuthal direction or antenna HAAT, or both, that exceed the initial technical facilities specified for the allotment in Appendix B of the Memorandum Opinion and Order (referenced in paragraph (c) of this section), up to the maximum permissible limits on DTV power and antenna height set forth in paragraph (f)(6), (f)(7), or (f)(8) of this section, as appropriate, or up to that needed to provide the same geographic coverage area as the largest station within their market, whichever would allow the largest service area. Such requests must be accompanied by a technical showing that the increase complies with the technical criteria in §73.623(c), and thereby will not result in new interference exceeding the de minimis standard set forth in that section, or statements agreeing to the change from any co-channel or adjacent channel stations that might be affected by potential new interference, in accordance with §73.623(f). In the case where a DTV station has been granted authority to construct pursuant to §73.623(c), and its authorized coverage area extends in any azimuthal direction beyond the DTV coverage area determined for the DTV allotment reference facilities, then the authorized DTV facilities are to be used in addition to the assumed facilities of the initial DTV allotment to determine protection from new DTV allotments pursuant to §73.623(d) and from subsequent DTV applications filed pursuant to §73.623(c). The provisions of this paragraph regarding increases in the ERP or antenna height of DTV stations on channels in the initial DTV Table of Allotments shall also apply in cases where the licensee or permittee seeks to change the station's channel as well as alter its ERP and antenna HAAT. Licensees and permittees are advised that where a channel change is requested, it may, in fact, be necessary in specific cases for the station to operate with reduced power, a lower antenna, or a directional antenna to avoid causing new interference to another station.

(6) A DTV station that operates on a channel 2–6 allotment created subsequent to the initial DTV Table will be allowed a maximum ERP of 10 kW if its antenna HAAT is at or below 305 meters and it is located in Zone I or a maximum ERP of 45 kW if its antenna HAAT is at or below 305 meters and it is located in Zone II or Zone III. A DTV station that operates on a channel 2–6 allotment included in the initial DTV Table of Allotments may request an increase in power and/or antenna HAAT up to these maximum levels, provided the increase also complies with the provisions of paragraph (f)(5) of this section.

(i) At higher HAAT levels, such DTV stations will be allowed to operate with lower maximum ERP levels in accordance with the following table and formulas (the allowable maximum ERP for intermediate values of HAAT is determined using linear interpolation based on the units employed in the table):

(ii) For DTV stations located in Zone I that operate on channels 2–6 with an HAAT that exceeds 305 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERP_max=92.57–33.24*log₁₀(HAAT)

(iii) For DTV stations located in Zone II or III that operate on channels 2–6 with an HAAT that exceeds 610 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERP_max=57.57–17.08*log₁₀(HAAT)

(7) A DTV station that operates on a channel 7–13 allotment created subsequent to the initial DTV Table will be allowed a maximum ERP of 30 kW if its antenna HAAT is at or below 305 meters and it is located in Zone I or a maximum ERP of 160 kW if its antenna HAAT is at or below 305 meters and it is located in Zone II or Zone III. A DTV station that operates on a channel 7–13 allotment included in the initial DTV Table of Allotments may request an increase in power and/or antenna HAAT up to these maximum levels, provided the increase also complies with the provisions of paragraph (f)(5) of this section.

(i) At higher HAAT levels, such DTV stations will be allowed to operate with lower maximum ERP levels in accordance with the following table and formulas (the allowable maximum ERP for intermediate values of HAAT is determined using linear interpolation based on the units employed in the table):

(ii) For DTV stations located in Zone I that operate on channels 7–13 with an HAAT that exceeds 305 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERP_max=97.35–33.24*log₁₀(HAAT)

(iii) For DTV stations located in Zone II or III that operate on channels 7–13 with an HAAT that exceeds 610 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERP_max=62.34–17.08*log₁₀(HAAT)

(8) A DTV station that operates on a channel 14–59 allotment created subsequent to the initial DTV Table will be allowed a maximum ERP of 1000 kW if their antenna HAAT is at or below 365 meters. A DTV station that operates on a channel 14–59 allotment included in the initial DTV Table of Allotments may request an increase in power and/or antenna HAAT up to these maximum levels, provided the increase also complies with the provisions of paragraph (f)(5) of this section.

(i) At higher HAAT levels, such DTV stations will be allowed to operates with lower maximum ERP levels in accordance with the following table and formulas (the allowable maximum ERP for intermediate values of HAAT is determined using linear interpolation based on the units employed in the table):

(ii) For DTV stations located in Zone I, II or III that operate on channels 14–59 with an HAAT that exceeds 610 meters, the allowable maximum ERP expressed in decibels above 1 kW (dBk) is determined using the following formula, with HAAT expressed in meters:

ERP_max=72.57–17.08*log₁₀(HAAT)

(g) DTV stations operating on channels above an analog TV station. (1) DTV stations operating on a channel allotment designated with a “c” in paragraph (b) of this section must maintain the pilot carrier frequency of the DTV signal 5.082138 MHz above the visual carrier frequency of any analog TV broadcast station that operates on the lower adjacent channel and is located within 88 kilometers. This frequency difference must be maintained within a tolerance of ±3 Hz.

(2) Unless it conflicts with operation complying with paragraph (g)(1) of this section, where a low power television station or TV translator station is operating on the lower adjacent channel within 32 km of the DTV station and notifies the DTV station that it intends to minimize interference by precisely maintaining its carrier frequencies, the DTV station shall cooperate in locking its carrier frequency to a common reference frequency and shall be responsible for any costs relating to its own transmission system in complying with this provision.

(h)(1) The power level of emissions on frequencies outside the authorized channel of operation must be attenuated no less than the following amounts below the average transmitted power within the authorized channel. In the first 500 kHz from the channel edge the emissions must be attenuated no less than 47 dB. More than 6 MHz from the channel edge, emissions must be attenuated no less than 110 dB. At any frequency between 0.5 and 6 MHz from the channel edge, emissions must be attenuated no less than the value determined by the following formula:

Attenuation in dB = −11.5(Δf + 3.6);

Where: Δf = frequency difference in MHz from the edge of the channel.

(2) This attenuation is based on a measurement bandwidth of 500 kHz. Other measurement bandwidths may be used as long as appropriate correction factors are applied. Measurements need not be made any closer to the band edge than one half of the resolution bandwidth of the measuring instrument. Emissions include sidebands, spurious emissions and radio frequency harmonics. Attenuation is to be measured at the output terminals of the transmitter (including any filters that may be employed). In the event of interference caused to any service, greater attenuation may be required.

[62 FR 26712, May 14, 1997]

Editorial Note:  For Federal Register citations affecting §73.622, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO Access.

Effective Date Note:  At 67 FR 70018, Nov. 20, 2002, §73.622 was amended in the Table of Allotments in paragraph (b) under California by adding Avalon, DTV channel 47c. This amendment will become effective 60 days after the concurrence of the Mexican government is obtained. The FCC will publish a document announcing when the concurrence has been obtained and giving the effective date.

§ 73.623   DTV applications and changes to DTV allotments.

(a) General. This section contains the technical criteria for evaluating applications requesting DTV facilities that do not conform to the provisions of §73.622 and petitions for rule making to amend the DTV Table of Allotments (§73.622(b)). Petitions to amend the DTV Table (other than those also expressly requesting amendment of this section) and applications for new DTV broadcast stations or for changes in authorized DTV stations filed pursuant to this section will not be accepted for filing if they fail to comply with the requirements of this section.

(b) In considering petitions to amend the DTV Table and applications filed pursuant to this section, the Commission will use geographic coordinates defined in §73.622(d) as reference points in determining allotment separations and evaluating interference potential.

(c) Minimum technical criteria for modification of DTV allotments included in the initial DTV Table of Allotments and for applications filed pursuant to this section. No petition to modify a channel allotment included in the initial DTV Table of Allotments or application for authority to construct or modify a DTV station assigned to such an allotment, filed pursuant to this section, will be accepted unless it shows compliance with the requirements of this paragraph.

(1) Requests filed pursuant to this paragraph must demonstrate compliance with the principal community coverage requirements of section 73.625(a).

(2) Requests filed pursuant to this paragraph must demonstrate that the requested change would not result in more than an additional 2 percent the population served by another station being subject to interference; provided, however, that no new interference may be caused to any station that already experiences interference to 10 percent or more of its population or that would result in a station receiving interference in excess of 10 percent of its population. The station population values for existing NTSC service and DTV service contained in Appendix B of the Memorandum Opinion and Order on Reconsideration of the Sixth Report and Order in MM Docket No. 87–268, FCC 98–24, adopted January 29, 1998, referenced in §73.622(c), are to be used for the purposes of determining whether a power increase or other change is permissible under this de minimis standard. For evaluating compliance with this requirement, interference to populations served is to be predicted based on the procedure set forth in OET Bulletin No. 69, including population served within service areas determined in accordance with section 73.622(e), consideration of whether F(50,10) undesired signals will exceed the following desired-to-undesired (D/U) signal ratios, assumed use of a directional receiving antenna, and use of the terrain dependent Longley-Rice point-to-point propagation model. Copies of OET Bulletin No. 69 may be inspected during normal business hours at the: Federal Communications Commission, Room CY-C203, 445 12th Street, SW., Reference Information Center, Washington, DC 20554. These documents are also available through the Internet on the FCC Home Page at http://www.fcc.gov. The threshold levels at which interference is considered to occur are:

(3) The values in paragraph (c)(2) of this section for co-channel interference to DTV service are only valid at locations where the signal-to-noise ratio is 28 dB or greater for interference from DTV and 25 dB or greater for interference from analog TV service. At the edge of the noise-limited service area, where the signal-to-noise (S/N) ratio is 16 dB, these values are 21 dB and 23 dB for interference from analog TV and DTV, respectively. At locations where the S/N ratio is greater than 16 dB but less than 28 dB, D/U values for co-channel interference to DTV are as follows:

(i) For DTV-to-DTV interference, the minimum D/U ratios are computed from the following formula:

D/U = 15+10log₁₀[1.0/(1.0−10^−x/10)]

Where x = S/N–15.19 (minimum signal to noise ratio)

(ii) For analog-to-DTV interference, the minimum D/U ratios are found from the following Table (for values between measured values, linear interpolation can be used):

(4) Due to the frequency spacing that exists between Channels 4 and 5, between Channels 6 and 7, and between Channels 13 and 14, the minimum adjacent channel technical criteria specified in paragraph (c)(2) of this section shall not be applicable to these pairs of channels (see §73.603(a)).

(5) A DTV station application that proposes to expand the DTV station's allotted or authorized coverage area in any direction will not be accepted if it is predicted to cause interference to a Class A TV station or to a digital Class A TV station authorized pursuant to Subpart J of this part, within the protected contour defined in §73.6010 of this part. This paragraph applies to all DTV applications filed after May 1, 2000, and to DTV applications filed between December 31, 1999 and April 30, 2000 unless the DTV station licensee or permittee notified the Commission of its intent to “maximize” by December 31, 1999.

(i) Interference is predicted to occur if the ratio in dB of the field strength of a Class A TV station at its protected contour to the field strength resulting from the facilities proposed in the DTV application (calculated using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699 of this part) fails to meet the D/U signal ratios for “DTV-into-analog TV” specified in paragraph (c)(2) of this section.

(ii) Interference is predicted to occur if the ratio in dB of the field strength of a digital Class A TV station at its protected contour to the field strength resulting from the facilities proposed in the DTV application (calculated using the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §73.699 of this part) fails to meet the D/U signal ratios for “DTV-into-DTV” specified in paragraphs (c)(2) and (c)(3) of this section.

(iii) In support of a request for waiver of the interference protection requirements of this section, an applicant for a DTV broadcast station may make full use of terrain shielding and Longley-Rice terrain dependent propagation methods to demonstrate that the proposed facility would not be likely to cause interference to Class A TV stations. Guidance on using the Longely-Rice methodology is provided in OET Bulletin No. 69, which is available through the Internet at http://www.fcc.gov/oet/info/documents/bulletins/#69.

(d) Minimum geographic spacing requirements for DTV allotments not included in the initial DTV Table of Allotments. No petition to add a new channel to the DTV Table of Allotments or modify an allotment not included in the initial DTV Table will be accepted unless it shows compliance with the requirements of this paragraph.

(1) Requests filed pursuant to this paragraph must demonstrate compliance with the principle community coverage requirements of section 73.625(a).

(2) Requests filed pursuant to this paragraph must meet the following requirements for geographic spacing with regard to all other DTV stations, DTV allotments and analog TV stations:

(3) Zones are defined in §73.609. The minimum distance separation between a DTV station in one zone and an analog TV or DTV station in another zone shall be that of the zone requiring the lower separation.

(4) Due to the frequency spacing that exists between Channels 4 and 5, between Channels 6 and 7, and between Channels 13 and 14, the minimum geographic spacing requirements specified in paragraph (d)(3) of this section shall not be applicable to these pairs of channels (§73.603(a)).

(e) Protection of land mobile operations on channels 14–20. The Commission will not accept petitions to amend the DTV Table of Allotments, applications for new DTV stations, or applications to change the channel or location of authorized DTV stations that would use channels 14–20 where the distance between the DTV reference point as defined in section 73.622(d), would be located less than 250 km from the city center of a co-channel land mobile operation or 176 km from the city center of an adjacent channel land mobile operation. Petitions to amend the DTV Table, applications for new DTV stations, or requests to modify the DTV Table that do not meet the minimum DTV-to-land mobile spacing standards will, however, be considered where all affected land mobile licensees consent to the requested action. Land mobile operations are authorized on these channels in the following markets:

(f) Parties requesting new allotments on channel 6 be added to the DTV Table must submit an engineering study demonstrating that no interference would be caused to existing FM radio stations on FM channels 200–220.

(g) Negotiated agreements on interference. Notwithstanding the minimum technical criteria for DTV allotments specified above, DTV stations operating on allotments that are included in the initial DTV Table may: operate with increased ERP and/or antenna HAAT that would result in additional interference to another DTV station or an analog TV station if that station agrees, in writing, to accept the additional interference; and/or implement an exchange of channel allotments between two or more licensees or permittees of TV stations in the same community, the same market, or in adjacent markets provided, however, that the other requirements of this section and of section 73.622 are met with respect to each such application. Such agreements must be submitted with the application for authority to construct or modify the affected DTV station or stations. The larger service area resulting from a negotiated change in ERP and/or antenna HAAT will be protected in accordance with the provisions of paragraph (c) of this section. Negotiated agreements under this paragraph can include the exchange of money or other considerations from one station to another, including payments to and from noncommercial television stations assigned reserved channels. Applications submitted pursuant to the provisions of this paragraph will be granted only if the Commission finds that such action is consistent with the public interest.

(h) DTV application processing. (1) DTV applications for a construction permit or a modified construction permit pending as of January 18, 2001:

(i) Shall be afforded the interference protection set forth in paragraph (c) or (d) of this section, as applicable:

(A) By all NTSC minor change applications;

(B) By NTSC new station applications, except those covered by paragraphs (h)(1)(ii)(G) and (h)(1)(iii)(D) of this section;

(C) By all rulemaking petitions to amend the NTSC TV table of allotments;

(D) By DTV applications filed after January 18, 2001; and

(E) By rulemaking petitions to amend the DTV table of allotments filed after January 18, 2001;

(ii) Must demonstrate the requisite interference protection set forth in paragraph (c) or (d) of this section, as applicable, to:

(A) DTV licensed stations;

(B) DTV construction permits;

(C) Existing DTV allotments;

(D) Rulemaking petitions to amend the DTV table of allotments for which a Notice of Proposed Rule Making has been released and the comment deadline specified therein has passed prior to the filing date of the DTV application;

(E) NTSC stations with licenses covering construction permits that were granted before the DTV application was filed;

(F) NTSC construction permits that were granted before the DTV application was filed;

(G) Applications for new NTSC television stations that were in groups of mutually exclusive applications on file prior to July 1, 1997, regardless of whether they are the only applications that remain pending from their group.

(iii) That do not provide the requisite interference protection set forth in paragraph (c) or (d) of this section, as applicable, to the following applications and petitions will be deemed mutually exclusive with those applications and petitions:

(A) Other DTV applications pending as of January 18, 2001;

(B) Rulemaking petitions to amend the DTV table of allotments filed on or before January 18, 2001 for which a Notice of Proposed Rule Making had been released and the comment deadline specified therein had not passed prior to the filing date of the DTV application;

(C) Rulemaking petitions to amend the DTV table of allotments filed on or before January 18, 2001 for which a Notice of Proposed Rule Making had not been released; and

(D) Applications for new NTSC stations that are not covered by paragraph (h)(1)(ii)(G) of this section and were filed and accepted for filing on or before January 18, 2001 that:

(1) Were filed by post-auction winners pursuant to §73.5005.

(2) Are part of a settlement agreement on-file with the Commission that would result in the grant of the NTSC application; or

(3) Are cut-off singletons.

(2) DTV applications for a construction permit or a modified construction permit filed after January 18, 2001:

(i) Shall be afforded the interference protection set forth in paragraph (c) or (d) of this section, as applicable:

(A) By all NTSC minor change applications;

(B) By NTSC new station applications, except those covered by paragraph (h)(2)(ii)(H) and (I) of this section;

(C) By all rulemaking petitions to amend the NTSC TV table of allotments except those filed by NTSC applicants in those groups defined in (h)(2)(ii)(I) of this section for which a Notice of Proposed Rule Making has been released and the comment deadline specified therein has passed prior to the filing date of the DTV application;

(D) By later-filed DTV applications; and

(E) By later-filed rulemaking petitions to amend the DTV table of allotments;

(ii) Must demonstrate the requisite interference protection set forth in paragraph (c) or (d) of this section, as applicable, to:

(A) DTV licensed stations;

(B) DTV construction permits;

(C) Earlier-filed DTV applications;

(D) Existing DTV allotments;

(E) Rulemaking petitions to amend the DTV table of allotments for which a Notice of Proposed Rule Making has been released and the comment deadline specified therein has passed prior to the filing date of the DTV application;

(F) NTSC stations with licenses covering construction permits that were granted before the DTV application was filed;

(G) NTSC construction permits that were granted before the DTV application was filed; and

(H) Earlier-filed and accepted for filing applications for new NTSC stations that are not covered by paragraph (h)(2)(ii)(I) of this section, and that:

(1) Were filed by post-auction winners pursuant to §73.5005.

(2) Are part of a settlement agreement on-file with the Commission that would result in the grant of the NTSC application; or

(3) Are cut-off singletons;

(I) Applications for new NTSC television stations that were in groups of mutually exclusive applications on file prior to July 1, 1997, regardless of whether they are the only applications that remain pending from their group;

(J) Rulemaking petitions to amend the NTSC table of allotments filed by applicants defined in (h)(2)(ii)(I) of this section for which a Notice of Proposed Rule Making has been released and the comment deadline specified therein has passed prior to the filing of the DTV application.

(iii) That do not provide the requisite interference protection set forth in paragraph (c) or (d) of this section, as applicable, to the following applications and petitions will be deemed mutually exclusive with those applications and petitions:

(A) Other DTV applications filed the same day;

(B) Rulemaking petitions to amend the DTV table of allotments for which a Notice of Proposed Rule Making had been released and the comment deadline specified therein had not passed prior to the filing date of the DTV application; and

(C) Earlier-filed rulemaking petitions to amend the DTV table of allotments for which a Notice of Proposed Rule Making had not been released.

(3) DTV applicants, DTV applicants and NTSC applicants, or DTV applicants and DTV rulemaking petitioners that are mutually exclusive pursuant to this section will be notified by Public Notice and provided with a 90-day period of time to resolve their mutual exclusivity via engineering amendment or settlement. Those applications and petitions that remain mutually exclusive upon conclusion of the 90-day settlement period will be dismissed.

[62 FR 26719, May 14, 1997, as amended at 63 FR 13560, Mar. 20, 1998; 64 FR 4327, Jan. 28, 1999; 65 FR 30002, May 10, 2000; 65 FR 58467, Sept. 29, 2000; 66 FR 9984, Feb. 13, 2001; 66 FR 65134, Dec. 18, 2001; 69 FR 31906, June 8, 2004]

(a) Digital television (“DTV”) broadcast stations are assigned channels 6 MHz wide. Initial eligibility for licenses for DTV broadcast stations is limited to persons that, as of April 3, 1997, are licensed to operate a full power television broadcast station or hold a permit to construct such a station (or both).

(b) DTV broadcast station permittees or licensees must transmit at least one over-the-air video program signal at no direct charge to viewers on the DTV channel. Until such time as a DTV station permittee or licensee ceases analog transmissions and returns that spectrum to the Commission, and except as provided in paragraph (b)(1) of this section, at any time that a DTV broadcast station permittee or licensee transmits a video program signal on its analog television channel, it must also transmit at least one over-the-air video program signal on the DTV channel. The DTV service that is provided pursuant to this paragraph must be at least comparable in resolution to the analog television station programming transmitted to viewers on the analog channel.

(1) DTV broadcast station permittees and licensees required to construct and operate a DTV station by May 1, 2002, or May 1, 2003, pursuant to paragraph (d) of this section must, at a minimum, beginning on the date on which the DTV station is required to be constructed, provide a digital video program signal, of the quality described in paragraph (b) of this section, during prime time hours as defined in §79.3(a)(6) of this chapter. These licensees and permittees must also comply with the minimum operating hours requirements in paragraph (f) of this section.

(2) DTV licensees or permittees that choose to commence digital operation before the construction deadline set forth in paragraph (d) of this section are not subject to any minimum schedule for operation on the DTV channel.

(c) Provided that DTV broadcast stations comply with paragraph (b) of this section, DTV broadcast stations are permitted to offer services of any nature, consistent with the public interest, convenience, and necessity, on an ancillary or supplementary basis. The kinds of services that may be provided include, but are not limited to computer software distribution, data transmissions, teletext, interactive materials, aural messages, paging services, audio signals, subscription video, and any other services that do not derogate DTV broadcast stations' obligations under paragraph (b) of this section. Such services may be provided on a broadcast, point-to-point or point-to-multipoint basis, provided, however, that any video broadcast signal provided at no direct charge to viewers shall not be considered ancillary or supplementary.

(1) DTV licensees that provide ancillary or supplementary services that are analogous to other services subject to regulation by the Commission must comply with the Commission regulations that apply to those services, provided, however, that no ancillary or supplementary service shall have any rights to carriage under §§614 or 615 of the Communications Act of 1934, as amended, or be deemed a multichannel video programming distributor for purposes of section 628 of the Communications Act of 1934, as amended.

(2) In all arrangements entered into with outside parties affecting service operation, the DTV licensee or permittee must retain control over all material transmitted in a broadcast mode via the station's facilities, with the right to reject any material in the sole judgement of the permitte or licensee. The license or permittee is also responsible for all aspects of technical operation involving such telecommunications services.

(3) In any application for renewal of a broadcast license for a television station that provides ancillary or supplementary services, a licensee shall establish that all of its program services on the analog and the DTV spectrum are in the public interest. Any violation of the Commission's rules applicable to ancillary or supplementary services will reflect on the licensee's qualifications for renewal of its license.

(d) Digital television broadcast facilities that comply with the FCC DTV Standard (section 73.682(d)), shall be constructed in the following markets by the following dates:

(1)(i) May 1, 1999: all network-affiliated television stations in the top ten television markets;

(ii) November 1, 1999: all network-affiliated television stations not included in category (1)(i) and in the top 30 television markets;

(iii) May 1, 2002: all remaining commercial television stations;

(iv) May 1, 2003: all noncommercial television stations.

(2) For the purposes of paragraph (d)(1):

(i) The term, “network,” is defined to include the ABC, CBS, NBC, and Fox television networks;

(ii) The term, “television market,” is defined as the Designated Market Area or DMA as defined by Nielsen Media Research as of April 3, 1997; and

(iii) The terms, “network-affiliated” or “network-affiliate,” are defined to include those television stations affiliated with at least one of the four networks designated in paragraph (d)(2)(i) as of April 3, 1997. In those DMAs in which a network has more than one network affiliate, paragraphs (d)(1) (i) and (ii) of this section shall apply to its network affiliate with the largest audience share for the 9 a.m. to midnight time period as measured by Nielsen Media Research in its Nielsen Station Index, Viewers in Profile, as of February, 1997.

(3) Authority delegated. (i) Authority is delegated to the Chief, Media Bureau to grant an extension of time of up to six months beyond the relevant construction deadline specified in paragraph (d)(1) of this section upon demonstration by the DTV licensee or permittee that failure to meet that construction deadline is due to circumstances that are either unforeseeable or beyond the licensee's control where the licensee has taken all reasonable steps to resolve the problem expeditiously.

(ii) Such circumstances shall include, but shall not be limited to:

(A) Inability to construct and place in operation a facility necessary for transmitting digital television, such as a tower, because of delays in obtaining zoning or FAA approvals, or similar constraints;

(B) the lack of equipment necessary to obtain a digital television signal; or

(C) where the cost of meeting the minimum build-out requirements exceeds the station's financial resources.

(iii) The Bureau may grant no more than two extension requests upon delegated authority. Subsequent extension requests shall be referred to the Commission. The Bureau may deny extension requests upon delegated authority.

(iv) Applications for extension of time shall be filed no earlier than 90 and no later than 60 days prior to the relevant construction deadline, absent a showing of sufficient reasons for filing within less than 60 days of the relevant construction deadline.

(e) The application for construction permit must be filed on Form 301 (except for noncommercial stations, which must file on Form 340) on or before the date on which half of the construction period has elapsed. Thus, for example, for applicants in category (d)(1)(i), the application for construction period must be filed by May 1, 1998.

(f)(1) Commencing on April 1, 2003, DTV television licensees and permittees required to construct and operate a DTV station by May 1, 2002, or May 1, 2003, must transmit at least one over-the-air video program signal at no direct charge to viewers on their DTV channel at least 50 percent of the time they are transmitting a video program signal on their analog channel.

(2) Commencing on April 1, 2004, DTV licensees and permittees described in paragraph (f)(1) of this section must transmit a video program signal as described in paragraph (f)(1) of this section on the DTV channel at least 75 percent of the time they are transmitting a video program signal on the analog channel.

(3) Commencing on April 1, 2005, DTV licensees and permittees described in paragraph (f)(1) of this section must transmit a video program signal as described in paragraph (f)(1) of this section on the DTV channel at least 100 percent of the time they are transmitting a video program signal on the analog channel.

(4) The minimum operating hours requirements imposed in paragraphs (f) (1) through (3) of this section will terminate when the analog channel terminates operation and a 6 MHz channel is returned by the DTV licensee or permittee to the Commission.

(g) Commercial and noncommercial DTV licensees must annually remit a fee of five percent of the gross revenues derived from all ancillary or supplementary services, as defined by paragraph (b) of this section, which are feeable, as defined in paragraphs (g)(2)(i) through (ii) of this section.

(1)(i) All ancillary or supplementary services for which payment of a subscription fee or charge is required in order to receive the service are feeable. The fee required by this provision shall be imposed on any and all revenues from such services, including revenues derived from subscription fees and from any commercial advertisements transmitted on the service.

(ii) Any ancillary or supplementary service for which no payment is required from consumers in order to receive the service is feeable if the DTV licensee directly or indirectly receives compensation from a third party in return for the transmission of material provided by that third party (other than commercial advertisements used to support broadcasting for which a subscription fee is not required). The fee required by this provision shall be imposed on any and all revenues from such services, other than revenues received from a third party in return for the transmission of commercial advertisements used to support broadcasting for which a subscription fee is not required.

(2) Payment of fees. (i) Each December 1, all commercial and noncommercial DTV licensees will electronically report whether they provided ancillary or supplementary services in the twelve-month period ending on the preceding September 30. Licensees will further report, for the applicable period: (A) a brief description of the services provided; (B) which services were feeable ancillary or supplementary services; (C) whether any ancillary or supplementary services provided were not subject to a fee; (D) gross revenues received from all feeable ancillary and supplementary services provided during the applicable period; and (E) the amount of bitstream used to provide ancillary or supplementary services during the applicable period. Licensees will certify under penalty of perjury the accuracy of the information reported. Failure to file regardless of revenues from ancillary or supplementary services or provision of such services may result in appropriate sanctions.

(ii) If a commercial or noncommercial DTV licensee has provided feeable ancillary or supplementary services at any point during a twelve-month period ending on September 30, the licensee must additionally file the FCC's standard remittance form (Form 159) on the subsequent December 1. Licensees will certify the amount of gross revenues received from feeable ancillary or supplementary services for the applicable twelve-month period and will remit the payment of the required fee.

(iii) The Commission reserves the right to audit each licensee's records which support the calculation of the amount specified on line 23A of Form 159. Each licensee, therefore, is required to retain such records for three years from the date of remittance of fees.

[62 FR 26989, May 16, 1997, as amended at 63 FR 15784, Apr. 1, 1998; 63 FR 69216, Dec. 16, 1998; 64 FR 4327, Jan. 28, 1999; 66 FR 58982, Nov. 26, 2001; 66 FR 65135, Dec. 18, 2001; 67 FR 13232, Mar. 21, 2002; 67 FR 38423, June 4, 2002; 69 FR 59535, Oct. 4, 2004]

Effective Date Note:  At 66 FR 58982, Nov. 26, 2001, §73.624 was amended by revising the first sentence in paragraph (g)(2)(i). This amendment contains information collection requirements and will not become effective until approval has been given by the Office of Management and Budget.

§ 73.625   DTV coverage of principal community and antenna system.

(a) Transmitter location. (1) The DTV transmitter location shall be chosen so that, on the basis of the effective radiated power and antenna height above average terrain employed, the following minimum F(50,90) field strength in dB above one uV/m will be provided over the entire principal community to be served:

Note to paragraph (a)(1): These requirements above do not become effective until December 31, 2004 for commercial television licensees and December 31, 2005 for noncommercial television licensees. Prior to those dates, the following minimum F(50,90) field strength in dB above one uV/m must be provided over the entire principal community to be served:

(2) The location of the antenna must be so chosen that there is not a major obstruction in the path over the principal community to be served.

(3) For the purposes of this section, coverage is to be determined in accordance with paragraph (b) of this section. Under actual conditions, the true coverage may vary from these estimates because the terrain over any specific path is expected to be different from the average terrain on which the field strength charts were based. Further, the actual extent of service will usually be less than indicated by these estimates due to interference from other stations. Because of these factors, the predicted field strength contours give no assurance of service to any specific percentage of receiver locations within the distances indicated.

(b) Determining coverage. (1) In predicting the distance to the field strength contours, the F (50,50) field strength charts (Figures 9, 10 and 10b of §73.699 of this part) and the F (50,10) field strength charts (Figures 9a, 10a and 10c of §73.699 of this part) shall be used. To use the charts to predict the distance to a given F (50,90) contour, the following procedure is used: Convert the effective radiated power in kilowatts for the appropriate azimuth into decibel value referenced to 1 kW (dBk). Subtract the power value in dBk from the contour value in dBu. Note that for power less than 1 kW, the difference value will be greater than the contour value because the power in dBk is negative. Locate the difference value obtained on the vertical scale at the left edge of the appropriate F (50,50) chart for the DTV station's channel. Follow the horizontal line for that value into the chart to the point of intersection with the vertical line above the height of the antenna above average terrain for the appropriate azimuth located on the scale at the bottom of the chart. If the point of intersection does not fall exactly on a distance curve, interpolate between the distance curves below and above the intersection point. The distance values for the curves are located along the right edge of the chart. Using the appropriate F (50,10) chart for the DTV station's channel, locate the point where the distance coincides with the vertical line above the height of the antenna above average terrain for the appropriate azimuth located on the scale at the bottom of the chart. Follow a horizontal line from that point to the left edge of the chart to determine the F (50,10) difference value. Add the power value in dBk to this difference value to determine the F (50,10) contour value in dBu. Subtract the F (50,50) contour value in dBu from this F (50,10) contour value in dBu. Subtract this difference from the F (50,50) contour value in dBu to determine the F (50,90) contour value in dBu at the pertinent distance along the pertinent radial.

(2) The effective radiated power to be used is that radiated at the vertical angle corresponding to the depression angle between the transmitting antenna center of radiation and the radio horizon as determined individually for each azimuthal direction concerned. In cases where the relative field strength at this depression angle is 90% or more of the maximum field strength developed in the vertical plane containing the pertaining radial, the maximum radiation shall be used. The depression angle is based on the difference in elevation of the antenna center of radiation above the average terrain and the radio horizon, assuming a smooth spherical earth with a radius of 8,495.5 kilometers (5,280 miles) and shall be determined by the following equation:

A = 0.0277 square root of H

Where:

This formula is empirically derived for the limited purpose specified here. Its use for any other purpose may be inappropriate.

(3) Applicants for new DTV stations or changes in the facilities of existing DTV stations must submit to the FCC a showing as to the location of their stations' or proposed stations' contour. This showing is to include a map showing this contour, except where applicants have previously submitted material to the FCC containing such information and it is found upon careful examination that the contour locations indicated therein would not change, on any radial, when the locations are determined under this section. In the latter cases, a statement by a qualified engineer to this effect will satisfy this requirement and no contour maps need be submitted.

(4) The antenna height to be used with these charts is the height of the radiation center of the antenna above the average terrain along the radial in question. In determining the average elevation of the terrain, the elevations between 3.2–16.1 kilometers (2–10 miles) from the antenna site are employed. Profile graphs shall be drawn for 8 radials beginning at the antenna site and extending 16.1 kilometers (10 miles) therefrom. The radials should be drawn for each 45 degrees of azimuth starting with True North. At least one radial must include the principal community to be served even though such community may be more than 16.1 kilometers (10 miles) from the antenna site. However, in the event none of the evenly spaced radials include the principal community to be served and one or more such radials are drawn in addition to the 8 evenly spaced radials, such additional radials shall not be employed in computing the antenna height above average terrain. Where the 3.2–16.1 kilometers (2–10 mile) portion of a radial extends in whole or in part over large bodies of water (such as ocean areas, gulfs, sounds, bays, large lakes, etc., but not rivers) or extends over foreign territory but the contour encompasses land area within the United States beyond the 16.1 kilometers (10 mile) portion of the radial, the entire 3.2–16.1 kilometers (2–10 mile) portion of the radial shall be included in the computation of antenna height above average terrain. However, where the contour does not so encompass United States land area and (1) the entire 3.2–16.1 kilometers (2–10 mile) portion of the radial extends over large bodies of water or foreign territory, such radial shall be completely omitted from the computation of antenna height above average terrain, and (2) where a part of the 3.2–16.1 kilometers (2–10 mile) portion of a radial extends over large bodies of water or over foreign territory, only that part of the radial extending from the 3.2 kilometer (2 mile) sector to the outermost portion of land area within the United States covered by the radial shall be employed in the computation of antenna height above average terrain. The profile graph for each radial should be plotted by contour intervals of from 12.2–30.5 meters (40–100 feet) and, where the data permits, at least 50 points of elevation (generally uniformly spaced) should be used for each radial. In instances of very rugged terrain where the use of contour intervals of 30.5 meters (100 feet) would result in several points in a short distance, 61.0–122.0 meter (200–400 foot) contour intervals may be used for such distances. On the other hand, where the terrain is uniform or gently sloping the smallest contour interval indicated on the topographic map (see paragraph (b)(5) of this section) should be used, although only relatively few points may be available. The profile graphs should indicate the topography accurately for each radial, and the graphs should be plotted with the distance in kilometers as the abscissa and the elevation in meters above mean sea level as the ordinate. The profile graphs should indicate the source of the topographical data employed. The graph should also show the elevation of the center of the radiating system. The graph may be plotted either on rectangular coordinate paper or on special paper which shows the curvature of the earth. It is not necessary to take the curvature of the earth into consideration in this procedure, as this factor is taken care of in the charts showing signal strengths. The average elevation of the 12.9 kilometer (8 miles) distance between 3.2–16.1 kilometers (2–10 miles) from the antenna site should then be determined from the profile graph for each radial. This may be obtained by averaging a large number of equally spaced points, by using a planimeter, or by obtaining the median elevation (that exceeded for 50% of the distance) in sectors and averaging those values. In directions where the terrain is such that negative antenna heights or heights below 30.5 meters (100 feet) for the 3.2 to 16.1 kilometers (2 to 10 mile) sector are obtained, an assumed height of 30.5 meters (100 feet) shall be used for the prediction of coverage. However, where the actual contour distances are critical factors, a supplemental showing of expected coverage must be included together with a description of the method employed in predicting such coverage. In special cases, the Commission may require additional information as to terrain and coverage.

(5) In the preparation of the profile graph previously described, and in determining the location and height above sea level of the antenna site, the elevation or contour intervals shall be taken from the United States Geological Survey Topographic Quadrangle Maps, United States Army Corps of Engineers' maps or Tennessee Valley Authority maps, whichever is the latest, for all areas for which such maps are available. If such maps are not published for the area in question, the next best topographic information should be used. Topographic data may sometimes be obtained from State and Municipal agencies. Data from Sectional Aeronautical Charts (including bench marks) or railroad depot elevations and highway elevations from road maps may be used where no better information is available. In cases where limited topographic data is available, use may be made of an altimeter in a car driven along roads extending generally radially from the transmitter site. United States Geological Survey Topographic Quadrangle Maps may be obtained from the United States Geological Survey, Department of the Interior, Washington, D.C. 20240. Sectional Aeronautical Charts are available from the United States Coast and Geodetic Survey, Department of Commerce, Washington, D.C. 20235. In lieu of maps, the average terrain elevation may be computer generated, except in the cases of dispute, using elevations from a 30 second point or better topographic data file. The file must be identified and the data processed for intermediate points along each radial using linear interpolation techniques. The height above mean sea level of the antenna site must be obtained manually using appropriate topographic maps.

(c) Antenna system. (1) The antenna system shall be designed so that the effective radiated power at any angle above the horizontal shall be as low as the state of the art permits, and in the same vertical plane may not exceed the effective radiated power in either the horizontal direction or below the horizontal, whichever is greater.

(2) An antenna designed or altered to produce a noncircular radiation pattern in the horizontal plane is considered to be a directional antenna. Antennas purposely installed in such a manner as to result in the mechanical beam tilting of the major vertical radiation lobe are included in this category.

(3) Applications proposing the use of directional antenna systems must be accompanied by the following:

(i) Complete description of the proposed antenna system, including the manufacturer and model number of the proposed directional antenna.

(ii) Relative field horizontal plane pattern (horizontal polarization only) of the proposed directional antenna. A value of 1.0 should be used for the maximum radiation. The plot of the pattern should be oriented so that 0 degrees corresponds to true North. Where mechanical beam tilt is intended, the amount of tilt in degrees of the antenna vertical axis and the orientation of the downward tilt with respect to true North must be specified, and the horizontal plane pattern must reflect the use of mechanical beam tilt.

(iii) A tabulation of the relative field pattern required in paragraph (c)(3)(ii) of this section. The tabulation should use the same zero degree reference as the plotted pattern, and be tabulated at least every 10 degrees. In addition, tabulated values of all maxima and minima, with their corresponding azimuths, should be submitted.

(iv) Horizontal and vertical plane radiation patterns showing the effective radiated power, in dBk, for each direction. Sufficient vertical plane patterns must be included to indicate clearly the radiation characteristics of the antenna above and below the horizontal plane. In cases where the angles at which the maximum vertical radiation varies with azimuth, a separate vertical radiation pattern must be provided for each pertinent radial direction.

(v) All horizontal plane patterns must be plotted to the largest scale possible on unglazed letter-size polar coordinate paper (main engraving approximately 18 cm×25 cm (7 inches×10 inches)) using only scale divisions and subdivisions of 1, 2, 2.5. or 5 times 10-nth. All vertical plane patterns must be plotted on unglazed letter-size rectangular coordinate paper. Values of field strength on any pattern less than 10 percent of the maximum field strength plotted on that pattern must be shown on an enlarged scale.

(vi) The horizontal and vertical plane patterns that are required are the patterns for the complete directional antenna system. In the case of a composite antenna composed of two or more individual antennas, this means that the patterns for the composite antenna, not the patterns for each of the individual antennas, must be submitted.

(4) Where simultaneous use of antennas or antenna structures is proposed, the following provisions shall apply:

(i) In cases where it is proposed to use a tower of an AM broadcast station as a supporting structure for a DTV broadcast antenna, an appropriate application for changes in the radiating system of the AM broadcast station must be filed by the licensee thereof. A formal application (FCC Form 301, or FCC Form 340 for a noncommercial educational station) will be required if the proposal involves substantial change in the physical height or radiation characteristics of the AM broadcast antennas; otherwise an informal application will be acceptable. (In case of doubt, an informal application (letter) together with complete engineering data should be submitted.) An application may be required for other classes of stations when the tower is to be used in connection with a DTV station.

(ii) When the proposed DTV antenna is to be mounted on a tower in the vicinity of an AM station directional antenna system and it appears that the operation of the directional antenna system may be affected, an engineering study must be filed with the DTV application concerning the effect of the DTV antenna on the AM directional radiation pattern. Field measurements of the AM stations may be required prior to and following construction of the DTV station antenna, and readjustments made as necessary.

(5) Applications proposing the use of electrical beam tilt pursuant to section 73.622(f)(4) must be accompanied by the following:

(i) Complete description of the proposed antenna system, including the manufacturer and model number. Vertical plane radiation patterns conforming with paragraphs (c)(3)(iv), (c)(3)(v) and (c)(3)(vi) of this section.

(ii) For at least 36 evenly spaced radials, including 0 degrees corresponding to true North, a determination of the depression angle between the transmitting antenna center of radiation and the radio horizon using the formula in paragraph (b)(2) of this section.

(iii) For each such radial direction, the ERP at the depression angle, taking into account the effect of the electrical beam tilt, mechanical beam tilt, if used, and directional antenna pattern if a directional antenna is specified.

(iv) The maximum ERP toward the radio horizon determined by this process must be clearly indicated. In addition, a tabulation of the relative fields representing the effective radiation pattern toward the radio horizon in the 36 radial directions must be submitted. A value of 1.0 should be used for the maximum radiation.

[62 FR 26990, May 16, 1997, as amended at 63 FR 13562, Mar. 20, 1998; 66 FR 9985, Feb. 13, 2001; 66 FR 65135, Dec. 18, 2001]

No television license or renewal of a television license will be granted to any person who owns, leases, or controls a particular site which is peculiarly suitable for television broadcasting in a particular area and (a) which is not available for use by other television licensees; and (b) no other comparable site is available in the area; and (c) where the exclusive use of such site by the applicant or licensee would unduly limit the number of television stations that can be authorized in a particular area or would unduly restrict competition among television stations.

[28 FR 13660, Dec. 14, 1963]

(a) Subscription television. A system whereby subscription television programs are transmitted and received.

(b) Subscription television program. A television boadcast program intended to be received in intelligible form for a fee or charge.

[52 FR 6154, Mar. 2, 1987]

(a) Subscription TV service may be provided by:

(1) Licensees and permittees of commercial and noncommercial TV stations, and

(2) Licensees and permittees of low power TV stations.

(b) A licensee or permittee of a commercial or noncommercial TV station or a low power TV station may begin subscription TV service upon installation of encoding equipment having advance FCC approval. However, the licensee or permittee of a TV broadcast station (not applicable to low power TV stations) must send a letter to the FCC in Washington, DC, that subscription TV service will commence at least 30 days prior to commencement of such service. In that letter, to be entitled “Notice of Commencement of STV Operations,” the licensee or permittee is to state that it will comply with the provisions of paragraphs (e)(1) through (e)(3) and §73.644(c) of this chapter and identify the make and type of encoding system to be used. A similar notice must be submitted if the licensee or permittee commences using another type of encoding system. (See section 644(h).) A notice must also be submitted to the FCC in Washington, DC, if encoded subscription TV service is to be discontinued, at least 30 days prior to such discontinuance.

(c) The station proof of system compliance measurement data (see §73.644(c)) need not be submitted to the FCC, however, the measurement data must be available to the FCC upon request.

(d) The use of the visual vertical blanking interval or an aural subcarrier for transmitting subscriber decoder control code signals during periods of normal non-encoded programming may be used only upon specific FCC authorization. Letter requests to use either the video blanking intervals or aural subcarriers during periods of non-subscription programming are to be sent to the FCC in Washington, D.C.

(e) A licensee or permittee of a commercial or noncommercial TV broadcast or low power TV station may not transmit a subscription service if it has a contract, arrangement, or understanding expressed or implied, that:

(1) Prevents or hinders it from rejecting or refusing any subscription TV broadcast program that it reasonably believes to be unsatisfactory or unsuitable or contrary to the public interests; or substituting a subscription or conventional program that, in its opinion, is of greater local or national importance; or

(2) Delegates to any other person the right to schedule the hours of transmission of subscription programs. However, this rule does not prevent a licensee or permittee from entering into an agreement or arrangement whereby it agrees to schedule a specific subscription TV broadcast program at a specific time or to schedule a specific number of hours of subscription programs during the broadcast day (or segments thereof) or weeks; or

(3) Deprives it of the right of ultimate decision concerning the maximum amount of any subscription program charge or fee.

(4) Has provisions that do not comply with the following policies of the FCC:

(i) Unless a satifactory signal is unavailable at the location where service is desired, subscription TV service must be provided to all persons desiring it within the Grade A contour of the station broadcasting subscription programs. Geographic or other reasonable patterns of installation for new subscription services is permitted and, for good cause, service may be terminated.

(ii) Charges, terms and conditions of service to subscribers must be applied uniformly. However, subscribers may be divided into reasonable classifications approved by the FCC, and the impositions of different sets of terms and conditions may be applied to subscribers in different classifications. Further, for good cause, within such classification, deposits may be required from some subscribers and not of others; and, also for good cause, if a subscription system generally uses a credit-type decoder, cash operated decoders may be installed for some subscribers.

[48 FR 56392, Dec. 21, 1983, as amended at 52 FR 6154, Mar. 2, 1987; 66 FR 58982, Nov. 26, 2001]

The non-technical rules and policies applicable to regular TV broadcast stations are applicable to subscription TV operations, except where specifically exempted in the provisions of those rules and policies.

[48 FR 56392, Dec. 21, 1983]

(a) Licensees and permittees of commercial and noncommercial TV broadcast and low power TV stations may conduct subscription operations only by using an encoding system that has been approved in advance by the FCC. Such advance approval may be applied for and granted in accordance with the procedures given in Subpart M Part 2 of the Rules.

(b) The criteria for advance approval of subscription TV transmitting systems by the FCC are as follows:

(1) Spectral energy in the transmitted signal must not exceed the limitations given in §73.687(e).

(2) No increase in width of the television broadcast channel (6 MHz.) is permitted.

(3) The technical system must enable stations to transmit encoded subscription TV programs without increasing the RMS output power from either the video or audio transmitters over that required to transmit the same program material using normal transmission standards.

(4) Modification of a type accepted TV broadcast or low power TV transmitter for encoded transmissions must not render transmitter incapable of operating in accordance with the operating specifications upon which type acceptance was granted. (See §2.1001 (b), (k))

(5) Interference to reception of conventional television either of co-channel or adjacent channel stations must not increase over that resulting from the transmission of programming with normal transmission standards.

(6) Subscriber decoder devices must meet the provisions, where required, of Subpart H of Part 15 of the FCC Rules for TV Interface Devices.

(c) Prior to commencing the transmission of encoded subscription programming, the licensee or permittee of a TV broadcast or low power TV station must perform such tests and measurements to determine that the transmitted encoded signal conforms to the radiated radio frequency and demodulated baseband and waveforms, transmitter operating power determination, and the occupied bandwidth limitations specified in the application for advance FCC approval of the system being used. A copy of the measurement data is to be maintained in the station files and made available to the FCC upon request.

(d) The licensee of a station transmitting an encoded subscription service must have at the transmitter control point the technical specifications for the system being used of both the aural and visual baseband signals and the transmitted radiofrequency signals, and have the necessary measuring and monitoring equipment, including transmitter output power measuring equipment, to determine that the transmissions conform to the advance approval specifications on file with the FCC. Full operating specifications for the system must be available to representatives of the FCC upon request.

(e) The operating power of the transmitters during encoded operations must be determined and maintained according to the procedures given in the application for advance approval.

(f) A station using an encoding system in accordance with the specifications filed with the application for advance approval is deemed to be exempted from those technical regulations of this Subpart and Subpart H to the extent they are specifically detailed in the application.

(g) No protection from interference of any kind will be afforded to reception of encoded subscription programming over that afforded reception of non-encoded signals.

(h) A licensee or permittee may make no modifications on a subscription encoding system that would alter the characteristics of the transmitted aural or visual signal from those specified in the application for advance approval. A licensee or permittee of a station replacing its encoding system must perform the measurements required by paragraph (c) of this section. A TV broadcast station licensee or permittee must also send a letter advising the FCC of the new system being used as required by §73.642(b) of this chapter.

(i) The station licensee is fully responsible for all technical operations of the station during transmissions of encoded subscription programming, regardless of the supplier of the encoding equipment or subscription program service.

Note: Stations transmitting encoded subscription programming prior to October 1, 1983, must comply with all technical and operating requirements of this Section no later than April 1, 1984. Stations not having the information to comply with this Section must obtain such information from the manufacturer of the encoding system being used, and if necessary, by measurements of the station's transmission system.

(j) Upon request by an authorized representative of the FCC, the licensee of a TV station transmitting encoded programming must make available a receiving decoder to the Commission to carry out its regulatory responsibilities.

[48 FR 56392, Dec. 21, 1983, as amended at 57 FR 48333, Oct. 23, 1992; 66 FR 58982, Nov. 26, 2001]

(a) Telecommunications services permitted on the vertical blanking interval (VBI) and in the visual signal include the transmission of data, processed information, or any other communication in either a digital or analog mode.

(b) Telecommunications service on the VBI and in the visual signal is of an ancillary nature and as such is an elective, subsidiary activity. No service guidelines, limitations, or performance standards are applied to it. The kinds of service that may be provided include, but are not limited to, teletext, paging, computer software and bulk data distribution, and aural messages. Such services may be provided on a broadcast, point-to-point, or point to multipoint basis.

(c) Telecommunications services that are common carrier in nature are subject to common carrier regulation. Licensees operating such services are required to apply to the Commission for the appropriate authorization and to comply with all policies and rules applicable to the particular service.

(d) Television licensees are authorized to lease their VBI and visual signal telecommunications facilities to outside parties. In all arrangements entered into with outside parties affecting telecommunications service operation, the licensee or permittee must retain control over all material transmitted in a broadcast mode via the station's facilities, with the right to reject any material that it deems inappropriate or undesirable. The licensee or permittee is also responsible for all aspects of technical operation involving such telecommunications services.

(e) The grant or renewal of a TV station license or permit will not be furthered or promoted by proposed or past VBI or visual signal telecommunications service operation; the licensee must establish that its broadcast operation serves the public interest wholly apart from such telecommunications service activities. (Violation of rules applicable to VBI and visual signal telecommunications services could, of course, reflect on a licensee's qualifications to hold its license or permit.)

(f) TV broadcast stations are authorized to transmit VBI and visual telecommunications service signals during any time period, including portions of the day when normal programming is not broadcast. Such transmissions must be in accordance with the technical provisions of §73.682.

[50 FR 4663, Feb. 1, 1985, as amended at 50 FR 9035, Mar. 6, 1985; 61 FR 36304, July 10, 1996]

The aural and visual transmitters may be operated independently of each other or, if operated simultaneously, may be used with different and unrelated program material.

[54 FR 9806, Mar. 8, 1989]

(a) Exclusive affiliation of station. No license shall be granted to a television broadcast station having any contract, arrangement, or understanding, express or implied, with a network organization under which the station is prevented or hindered from, or penalized for, broadcasting the programs of any other network organization. (The term “network organization” as used in this section includes national and regional network organizations. See ch. VII, J, of Report on Chain Broadcasting.)

(b) Territorial exclusively. No license shall be granted to a television broadcast station having any contract, arrangement, or understanding, express or implied, with a network organization which prevents or hinders another broadcast station located in the same community from broadcasting the network's programs not taken by the former station, or which prevents or hinders another broadcast station located in a different community from broadcasting any program of the network organization. This section shall not be construed to prohibit any contract, arrangement, or understanding between a station and a network organization pursuant to which the station is granted the first call in its community upon the programs of the network organization. As employed in this paragraph, the term “community” is defined as the community specified in the instrument of authorization as the location of the station.

(c) [Reserved]

(d) Station commitment of broadcast time. No license shall be granted to a television broadcast station having any contract, arrangement, or understanding, express or implied, with any network organization, which provides for optioning of the station's time to the network organization, or which has the same restraining effect as time optioning. As used in this section, time optioning is any contract, arrangement, or understanding, express or implied, between a station and a network organization which prevents or hinders the station from scheduling programs before the network agrees to utilize the time during which such programs are scheduled, or which requires the station to clear time already scheduled when the network organization seeks to utilize the time.

(e) Right to reject programs. No license shall be granted to a television broadcast station having any contract, arrangement, or understanding, express or implied, with a network organization which, with respect to programs offered or already contracted for pursuant to an affiliation contract, prevents or hinders the station from:

(1) Rejecting or refusing network programs which the station reasonably believes to be unsatisfactory or unsuitable or contrary to the public interest, or

(2) Substituting a program which, in the station's opinion, is of greater local or national importance.

(f) [Reserved]

(g) Dual network operation. A television broadcast station may affiliate with a person or entity that maintains two or more networks of television broadcast stations unless such dual or multiple networks are composed of two or more persons or entities that, on February 8, 1996, were “networks” as defined in §73.3613(a)(1) of the Commission's regulations (that is, ABC, CBS, Fox, and NBC).

(h) Control by networks of station rates. No license shall be granted to a television broadcast station having any contract, arrangement, or understanding, express or implied, with a network organization under which the station is prevented or hindered from, or penalized for, fixing or altering its rates for the sale of broadcast time for other than the network's programs.

(i) No license shall be granted to a television broadcast station which is represented for the sale of non-network time by a network organization or by an organization directly or indirectly controlled by or under common control with a network organization, if the station has any contract, arrangement or understanding, express or implied, which provides for the affiliation of the station with such network organization: Provided, however, That this rule shall not be applicable to stations licensed to a network organization or to a subsidiary of a network organization.

(j)–(l) [Reserved]

(m) Territorial exclusivity in non-network arrangements. (1) No television station shall enter into any contract, arrangement, or understanding, expressed or implied; with a non-network program producer, distributor, or supplier, or other person; which prevents or hinders another television station located in a community over 56.3 kilometers (35 miles) away, as determined by the reference points contained in §76.53 of this chapter, (if reference points for a community are not listed in §76.53, the location of the main post office will be used) from broadcasting any program purchased by the former station from such non-network program producer, distributor, supplier, or other person, except that a television station may secure exclusivity against a television station licensed to another designated community in a hyphenated market specified in the market listing as contained in §76.51 of this chapter for those 100 markets listed, and for markets not listed in §76.51 of this chapter, the listing as contained in the Nielsen Media Research DMA Rankings for the most recent year at the time that the exclusivity contract, arrangement or understanding is complete under practices of the industry. As used in this paragraph, the term “community” is defined as the community specified in the instrument of authorization as the location of the station.

(2) Notwithstanding paragraph (m)(1) of this section, a television station may enter into a contract, arrangement, or understanding with a producer, supplier, or distributor of a non-network program if that contract, arrangement, or understanding provides that the broadcast station has exclusive national rights such that no other television station in the United States may broadcast the program.

Note 1: Contracts, arrangements, or understandings that are complete under the practices of the industry prior to August 7, 1973, will not be disturbed. Extensions or renewals of such agreements are not permitted because they would in effect be new agreements without competitive bidding. However, such agreements that were based on the broadcaster's advancing “seed money” for the production of a specific program or series that specify two time periods—a tryout period and period thereafter for general exhibition—may be extended or renewed as contemplated in the basic agreement.

Note 2: It is intended that the top 100 major television markets listed in §76.51 of this chapter shall be used for the purposes of this rule and that the listing of the top 100 television markets appearing in the ARB Television Market Analysis shall not be used. The reference in this rule to the listing of markets in the ARB Television Market Analysis refers to hyphenated markets below the top-100 markets contained in the ARB Television Market Analysis. If a community is listed in a hyphenated market in §76.51 and is also listed in one of the markets in the ARB listing, the listing in §76.51 shall govern.

Note 3: The provisions of this paragraph apply only to U.S. commercial television broadcast stations in the 50 states, and not to stations in Puerto Rico or the Virgin Islands, foreign stations or noncommercial educational television or “public” television stations (either by way of restrictions on their exclusivity or on exclusivity against them).

Note 4: New stations authorized in any community of a hyphenated market listed in §76.51 of this chapter or in any community of a hyphenated market listed in the ARB Television Market Analysis (for markets below the top-100 markets) are subject to the same rules as previously existing stations therein. New stations authorized in other communities are considered stations in separate markets unless and until §76.51 is amended by Commission action, or the ARB listing is changed.

(Sec. 5, 48 Stat. 1068 (47 U.S.C. 155))

[28 FR 13660, Dec. 14, 1963]

Editorial Note:  For Federal Register citations affecting §73.658, see the List of CFR Sections Affected which appears in the Finding Aids section of the printed volume and on GPO Access.

§§ 73.659-73.663   [Reserved]

(a) The operating power of each TV visual transmitter shall normally be determined by the direct method.

(b) Direct method, visual transmitter. The direct method of power determination for a TV visual transmitter uses the indications of a calibrated transmission line meter (responsive to peak power) located at the RF output terminals of the transmitter. The indications of the calibrated meter are used to observe and maintain the authorized operating power of the visual transmitter. This meter must be calibrated whenever any component in the metering circuit is repaired or replaced and as often as necessary to ensure operation in accordance with the provisions of §73.1560 of this part. The following calibration procedures are to be used:

(1) The transmission line meter is calibrated by measuring the average power at the output terminals of the transmitter, including any vestigial sideband and harmonic filters which may be used in normal operation. For this determination the average power output is measured while operating into a dummy load of substantially zero reactance and a resistance equal to the transmission line characteristic impedance. During this measurement the transmitter is to be modulated only by a standard synchronizing signal with blanking level set at 75% of peak amplitude as observed in an output waveform monitor, and with this blanketing level amplitude maintained throughout the time interval between synchronizing pulses.

(2) If electrical devices are used to determine the output power, such devices must permit determination of this power to within an accuracy of ±5% of the power indicated by the full scale reading of the electrical indicating instrument of the device. If temperature and coolant flow indicating devices are used to determine the power output, such devices must permit determination of this power to within an accuracy of ±4% of measured average power output. The peak power output is the power so measured in the dummy load multiplied by the factor 1.68. During this measurement the input voltage and current to the final radio frequency amplifier stage and the transmission line meter are to be read and compared with similar readings taken with the dummy load replaced by the antenna. These readings must be in substantial agreement.

(3) The meter must be calibrated with the transmitter operating at 80%, 100%, and 110% of the authorized power as often as may be necessary to maintain its accuracy and ensure correct transmitter operating power. In cases where the transmitter is incapable of operating at 110% of the authorized power output, the calibration may be made at a power output between 100% and 110% of the authorized power output. However, where this is done, the output meter must be marked at the point of calibration of maximum power output, and the station will be deemed to be in violation of this rule if that power is exceeded. The upper and lower limits of permissible power deviation as determined by the prescribed calibration, must be shown upon the meter either by means of adjustable red markers incorporated in the meter or by red marks placed upon the meter scale or glass face. These markings must be checked and changed, if necessary, each time the meter is calibrated.

(c) Indirect method, visual transmitter. The operating power is determined by the indirect method by applying an appropriate factor to the input power to the final radio-frequency amplifier stage of the transmitter using the following formula:

Transmitter output power=Ep × Ip × F

Where:

(1) If the above formula is not appropriate for the design of the transmitter final amplifier, use a formula specified by the transmitter manufacturer with other appropriate operating parameters.

(2) The value of the efficiency factor, F established for the authorized transmitter output power is to be used for maintaining the operating power, even though there may be some variation in F over the power operating range of the transmitter.

(3) The value of F is to be determined and a record kept thereof by one of the following procedures listed in order of preference:

(i) Using the most recent measurement data for calibration of the transmission line meter according to the procedures described in paragraph (b) of this section or the most recent measurements made by the licensee establishing the value of F. In the case of composite transmitters or those in which the final amplifier stages have been modified pursuant to FCC approval, the licensee must furnish the FCC and also retain with the station records the measurement data used as a basis for determining the value of F.

(ii) Using measurement data shown on the transmitter manufacturer's test data supplied to the licensee, provided that measurements were made at the authorized carrier frequency and transmitter output power.

(iii) Using the transmitter manufacturer's measurement data submitted to the FCC for type acceptance as shown in the instruction book supplied to the licensee.

Note: Refer to §73.1560 for aural transmitter output power levels.

[44 FR 58732, Oct. 11, 1979, as amended at 48 FR 44805, Sept. 30, 1983; 49 FR 4210, Feb. 3, 1984; 49 FR 22092, May 25, 1984; 49 FR 49851, Dec. 24, 1984; 50 FR 26568, June 27, 1985; 54 FR 9806, Mar. 8, 1989. Redesignated at 58 FR 62555, Nov. 29, 1993]

Licensees of TV broadcast stations may transmit, without further authorization from the FCC, subcarriers and signals within the composite baseband for the following purposes:

(a) Stereophonic (biphonic, quadraphonic, etc.) sound programs under the provisions of §§73.667 and 73.669.

(b) Transmission of signals relating to the operation of TV stations, such as relaying broadcast materials to other stations, remote cueing and order messages, and control and telemetry signals for the transmitting system.

(c) Transmission of pilot or control signals to enhance the station's program service such as (but not restricted to) activation of noise reduction decoders in receivers, for any other receiver control purpose, or for program alerting and program identification.

(d) Subsidiary communications services.

[49 FR 18105, Apr. 27, 1984]

(a) Subsidiary communications services are those transmitted within the TV aural baseband signal, but do not include services which enhance the main program broadcast service or exclusively relate to station operations (see §73.665(a), (b), and (c)). Subsidiary communications include, but are not limited to, services such as functional music, specialized foreign language programs, radio reading services, utility load management, market and financial data and news, paging and calling, traffic control signal switching, and point-to-point or multipoint messages.

(b) TV subsidiary communications services that are common carrier or private radio in nature are subject to common carrier or private radio regulation. Licensees operating such services are required to apply to the FCC for the appropriate authorization and to comply with all policies and rules applicable to the service. Responsibility for making the initial determinations of whether a particular activity requires separate authority rests with the TV station licensee or permittee. Initial determinations by licensees or permittees are subject to FCC examination and may be reviewed at the FCC's discretion.

(c) Subsidiary communications services are of a secondary nature under the authority of the TV station authorization, and the authority to provide such communications services may not be retained or transferred in any manner separate from the station's authorization. The grant or renewal of a TV station permit or license is not furthered or promoted by proposed or past subsidiary communications services. The permittee or licensee must establish that the broadcast operation is in the public interest wholly apart from the subsidiary communications services provided.

(d) The station identification, delayed recording, and sponsor identification announcement required by §§73.1201, 73.1208, and 73.1212 are not applicable to leased communications services transmitted via services that are not of a general broadcast nature.

(e) The licensee or permittee must retain control over all material transmitted in a broadcast mode via the station's facilities, with the right to reject any material that it deems inappropriate or undesirable.

[49 FR 18105, Apr. 27, 1984, as amended at 49 FR 27147, July 2, 1984; 56 FR 49707, Oct. 1, 1991]

(a) A TV broadcast station may without specific authority from the FCC, transmit multichannel aural programs upon installation of multichannel sound equipment. Prior to commencement of multichannel broadcasting, the equipment shall be measured in accordance with §73.1690(e).

(b) Multiplex subcarriers may be used by a TV station pursuant to the provisions of §73.665 and may be transmitted on a secondary, non-interference basis to broadcast programming without specific authority from the FCC. Transmissions must be conducted in accordance with the technical standards given in §73.682(c).

(c) In all arrangements entered into with outside parties affecting non-common carrier subcarrier operation, the licensee or permittee must retain control over all material transmitted over the station's facilities, with the right to reject any material which is deemed inappropriate or undesirable. Subchannel leasing arrangements must be kept in writing at the station and made available to the FCC upon request.

[49 FR 18106, Apr. 27, 1984]

(a) No commercial television broadcast station licensee shall air more than 10.5 minutes of commercial matter per hour during children's programming on weekends, or more than 12 minutes of commercial matter per hour on weekdays.

(b) The display of Internet Web site addresses during program material is permitted only if the Web site:

(1) Offers a substantial amount of bona fide program-related or other noncommercial content;

(2) Is not primarily intended for commercial purposes, including either e-commerce or advertising;

(3) The Web site's home page and other menu pages are clearly labeled to distinguish the noncommercial from the commercial sections; and

(4) The page of the Web site to which viewers are directed by the Web site address is not used for e-commerce, advertising, or other commercial purposes (e.g., contains no links labeled “store” and no links to another page with commercial material).

(c) The display of Web site addresses in children's programs is prohibited during both program material and commercial material when the site uses characters from the program to sell products or services.

Note 1: Commercial matter means air time sold for purposes of selling a product or service and promotions of television programs or video programming services other than children's educational and informational programming.

Note 2: For purposes of this section, children's programming refers to programs originally produced and broadcast primarily for an audience of children 12 years old and younger.

[70 FR 36, Jan. 3, 2005]

Effective Date Note:  At 71 FR 5177, Feb. 1, 2006, in §73.670, paragraphs (b) and (c) and Note 1 were stayed until further notice, effective Feb. 1, 2006.

§ 73.671   Educational and informational programming for children.

(a) Each commercial and noncommercial educational television broadcast station licensee has an obligation to serve, over the term of its license, the educational and informational needs of children through both the licensee's overall programming and programming specifically designed to serve such needs.

(b) Any special nonbroadcast efforts which enhance the value of children's educational and informational television programming, and any special effort to produce or support educational and informational television programming by another station in the licensee's marketplace, may also contribute to meeting the licensee's obligation to serve, over the term of its license, the educational and informational needs of children.

(c) For purposes of this section, educational and informational television programming is any television programming that furthers the educational and informational needs of children 16 years of age and under in any respect, including the child's intellectual/cognitive or social/emotional needs. Programming specifically designed to serve the educational and informational needs of children (“Core Programming”) is educational and informational programming that satisfies the following additional criteria:

(1) It has serving the educational and informational needs of children ages 16 and under as a significant purpose;

(2) It is aired between the hours of 7:00 a.m. and 10:00 p.m.;

(3) It is a regularly scheduled weekly program;

(4) It is at least 30 minutes in length;

(5) The program is identified as specifically designed to educate and inform children by the display on the television screen throughout the program of the symbol E/I;

(6) The educational and informational objective and the target child audience are specified in writing in the licensee's Children's Television Programming Report, as described in §73.3526(e)(11)(iii); and

(7) Instructions for listing the program as educational/informational, including an indication of the age group for which the program is intended, are provided by the licensee to publishers of program guides, as described in §73.673.

(d) Until analog channels are returned to the Commission, the Commission will apply the following processing guideline to analog stations in assessing whether a television broadcast licensee has complied with the Children's Television Act of 1990 (“CTA”) on its analog channel. A licensee that has aired at least three hours per week of Core Programming (as defined in paragraph (c) of this section and as averaged over a six month period) will be deemed to have satisfied its obligation to air such programming and shall have the CTA portion of its license renewal application approved by the Commission staff. A licensee will also be deemed to have satisfied this obligation and be eligible for such staff approval if the licensee demonstrates that it has aired a package of different types of educational and informational programming that, while containing somewhat less than three hours per week of Core Programming, demonstrates a level of commitment to educating and informing children that is at least equivalent to airing three hours per week of Core Programming. In this regard, specials, PSAs, short-form programs, and regularly scheduled non-weekly programs with a significant purpose of educating and informing children can count toward the three hour per week processing guideline. Licensees that do not meet these processing guidelines will be referred to the Commission, where they will have full opportunity to demonstrate compliance with the CTA (e.g., by relying in part on sponsorship of Core educational/informational programs on other stations in the market that increases the amount of Core educational and informational programming on the station airing the sponsored program and/or on special nonbroadcast efforts which enhance the value of children's educational and informational television programming).

(e) The Commission will apply the following processing guideline to digital stations in assessing whether a television broadcast licensee has complied with the Children's Television Act of 1990 (“CTA”) on its digital channel(s).

(1) A digital television licensee providing only one stream of free digital video programming will be subject to the 3 hour/week Core Programming processing guideline discussed in paragraph (d) of this section on that channel; i.e., a licensee that has aired at least three hours per week of Core Programming (as defined in paragraph (c) of this section and as averaged over a six month period) on its main program stream will be deemed to have satisfied its obligation to air such programming and shall have the CTA portion of its license renewal application approved by the Commission staff. A licensee will also be deemed to have satisfied this obligation and be eligible for such staff approval if the licensee demonstrates that it has aired a package of different types of educational and informational programming that, while containing somewhat less than three hours per week of Core Programming, demonstrates a level of commitment to educating and informing children that is at least equivalent to airing three hours per week of Core Programming. In this regard, specials, PSAs, short-form programs, and regularly scheduled non-weekly programs with a significant purpose of educating and informing children can count toward the three hour per week processing guideline. Licensees that do not meet these processing guidelines will be referred to the Commission, where they will have full opportunity to demonstrate compliance with the CTA (e.g., by relying in part on sponsorship of Core educational/informational programs on other stations in the market that increases the amount of Core educational and informational programming on the station airing the sponsored program and/or on special nonbroadcast efforts which enhance the value of children's educational and informational television programming).

(2)(i) A digital television licensee providing streams of free digital video programming in addition to its main program stream will be subject to the processing guideline described in paragraph (e)(1) of this section on its main program stream and to the following guideline applied to the additional programming: 1/2 hour per week of additional Core Programming (as defined in paragraph (c) of this section and as averaged over a six month period) for every increment of 1 to 28 hours of free video programming provided in addition to the main program stream. Thus, digital broadcasters providing between 1 and 28 hours per week of free video programming in addition to their main program stream will have a guideline of 1/2 hour per week of core programming in addition to the 3 hours per week on the main program stream. Digital broadcasters providing between 29 and 56 hours per week of free video programming in addition to their main program stream will have a guideline of 1 hour per week of core programming in addition to the 3 hours per week on the main program stream. Digital broadcasters providing between 57 and 84 hours per week of free video programming in addition to their main program stream will have a guideline of 11/2 hours per week of core programming in addition to the 3 hours per week on the main program stream. The guideline will continue to increase in this manner for additional hours of free video programming.

(ii) Broadcasters providing more than one stream of free digital video programming may air all of their additional core programming, apart from the 3 hours of core programming that must be aired on the main program stream, on one free video channel, or distribute it across multiple free video channels, at their discretion, as long as the stream on which the core programming is aired has comparable MVPD carriage as the stream whose programming generates the core programming obligation under the processing guideline described in paragraph (e)(2)(i) of this section.

(3) For purposes of the guideline described in paragraphs (e)(1) and (e)(2) of this section at least 50 percent of core programming cannot be repeated during the same week to qualify as core. This requirement does not apply to any program stream that merely time shifts the entire programming line-up of another program stream and, during the digital transition, to core programs aired on both the analog station and a digital program stream.

(f) No more than 10 percent of Core Programs may be preempted in each calendar quarter to qualify as Core Programming.

Note 1 to §73.671: For purposes of determining under this section whether programming has a significant purpose of serving the educational and informational needs of children, the Commission will ordinarily rely on the good faith judgments of the licensee. Commission review of compliance with that element of the definition will be done only as a last resort.

[56 FR 19616, Apr. 29, 1991. Redesignated at 56 FR 28825, June 25, 1991, as amended at 61 FR 43997, Aug. 27, 1996; 70 FR 37, Jan. 3, 2005]

Effective Date Note 1:  At 70 FR 37, Jan. 3, 2005, in §73.671, paragraph (c)(5) was revised, effective Jan. 1, 2006. This paragraph contains information collection and recordkeeping requirements and will not become effective until approval has been given by the Office of Management and Budget.

Effective Date Note 2:  At 71 FR 5177, Feb. 1, 2006, in §73.671, paragraphs (e) and (f) were stayed until further notice, effective Feb. 1, 2006.

§ 73.672   [Reserved]

Each commercial television broadcast station licensee shall provide information identifying programming specifically designed to educate and inform children to publishers of program guides. Such information shall include an indication of the age group for which the program is intended.

[70 FR 9877, Mar. 1, 2005]

Amplitude modulation (AM). A system of modulation in which the envelope of the transmitted wave contains a component similar to the wave form of the signal to be transmitted.

Antenna electrical beam tilt. The shaping of the radiation pattern in the vertical plane of a transmitting antenna by electrical means so that maximum radiation occurs at an angle below the horizontal plane.

Antenna height above average terrain. The average of the antenna heights above the terrain from approximately 3.2 (2 miles) to 16.1 kilometers (10 miles) from the antenna for the eight directions spaced evenly for each 45 degrees of azimuth starting with True North. (In general, a different antenna height will be determined in each direction from the antenna. The average of these various heights is considered the antenna height above the average terrain. In some cases less than 8 directions may be used. See §73.684(d)). Where circular or elliptical polarization is employed, the antenna height above average terrain shall be based upon the height of the radiation center of the antenna which transmits the horizontal component of radiation.

Antenna mechanical beam tilt. The intentional installation of a transmitting antenna so that its axis is not vertical, in order to change the normal angle of maximum radiation in the vertical plane.

Antenna power gain. The square of the ratio of the root-mean-square free space field strength produced at 1 kilometer in the horizontal plane, in millivolts per meter for one kW antenna input power to 221.4 mV/m. This ratio should be expressed in decibels (dB). (If specified for a particular direction, antenna power gain is based on the field strength in that direction only.)

Aspect ratio. The ratio of picture width to picture height as transmitted.

Aural center frequency. (1) The average frequency of the emitted wave when modulated by a sinusoidal signal; (2) the frequency of the emitted wave without modulation.

Aural transmitter. The radio equipment for the transmission of the aural signal only.

Auxiliary facility. An auxiliary facility is an antenna separate a from the main facility's antenna, permanently installed on the same tower or at a different location, from which a station may broadcast for short periods without prior Commission authorization or notice to the Commission while the main facility is not in operation (e.g., where tower work necessitates turning off the main antenna or where lightning has caused damage to the main antenna or transmission system) (See §73.1675).

BTSC. Broadcast Television systems committee recommendation for multichannel television sound transmission and audio processing as defined in FCC Bulletin OET 60.

Baseband. Aural transmitter input signals between 0 and 120 kHz.

Blanking level. The level of the signal during the blanking interval, except the interval during the scanning synchronizing pulse and the chrominance subcarrier synchronizing burst.

Chrominance. The colorimetric difference between any color and a reference color of equal luminance, the reference color having a specific chromaticity.

Chrominance subcarrier. The carrier which is modulated by the chrominance information.

Color transmission. The transmission of color television signals which can be reproduced with different values of hue, saturation, and luminance.

Effective radiated power. The product of the antenna input power and the antenna power gain. This product should be expressed in kW and in dB above 1 kW (dBk). (If specified for a particular direction, effective radiated power is based on the antenna power gain in that direction only. The licensed effective radiated power is based on the maximum antenna power gain. When a station is authorized to use a directional antenna or an antenna beam tilt, the direction of the maximum effective radiated power will be specified.) Where circular or elliptical polarization is employed, the term effective radiated power is applied separately to the horizontally and vertically polarized components of radiation. For assignment purposes, only the effective radiated power authorized for the horizontally polarized component will be considered.

Equivalent isotropically radiated power (EIRP). The term “equivalent isotropically radiated power” (also known as “effective radiated power above isotropic”) means the product of the antenna input power and the antenna gain in a given direction relative to an isotropic antenna.

Field. Scanning through the picture area once in the chosen scanning pattern. In the line interlaced scanning pattern of two to one, the scanning of the alternate lines of the picture area once.

Frame. Scanning all of the picture area once. In the line interlaced scanning pattern of two to one, a frame consists of two fields.

Free space field strength. The field strength that would exist at a point in the absence of waves reflected from the earth or other reflecting objects.

Frequency departure. The amount of variation of a carrier frequency or center frequency from its assigned value.

Frequency deviation. The peak difference between the instantaneous frequency of the modulated wave and the carrier frequency.

Frequency modulation (FM). A system of modulation where the instantaneous radio frequency varies in proportion to the instantaneous amplitude of the modulating signal (amplitude of modulating signal to be measured after pre-emphasis, if used) and the instantaneous radio frequency is independent of the frequency of the modulating signal.

Frequency swing. The peak difference between the maximum and the minimum values of the instantaneous frequency of the carrier wave during modulation.

Interlaced scanning. A scanning process in which successively scanned lines are spaced an integral number of line widths, and in which the adjacent lines are scanned during successive cycles of the field frequency.

IRE standard scale. A linear scale for measuring, in IRE units, the relative amplitudes of the components of a television signal from a zero reference at blanking level, with picture information falling in the positive, and synchronizing information in the negative domain.

Note: When a carrier is amplitude modulated by a television signal in accordance with §73.682, the relationship of the IRE standard scale to the conventional measure of modulation is as follows:

Luminance. Luminous flux emitted, reflected, or transmitted per unit solid angle per unit projected area of the source.

Main channel. The band of frequencies from 50 to 15,000 Hertz which frequency modulate the main aural carrier.

Monochrome transmission. The transmission of television signals which can be reproduced in gradations of a single color only.

Multichannel Television Sound (MTS). Any system of aural transmission that utilizes aural baseband operation between 15 kHz and 120 kHz to convey information or that encodes digital information in the video portion of the television signal that is intended to be decoded as audio information.

Multiplex Transmission (Aural). A subchannel added to the regular aural carrier of a television broadcast station by means of frequency modulated subcarriers.

Negative transmission. Where a decrease in initial light intensity causes an increase in the transmitted power.

Peak power. The power over a radio frequency cycle corresponding in amplitude to synchronizing peaks.

Percentage modulation. As applied to frequency modulation, the ratio of the actual frequency deviation to the frequency deviation defined as 100% modulation expressed in percentage. For the aural transmitter of TV broadcast stations, a frequency deviation of ±25 kHz is defined as 100% modulation.

Pilot subcarrier. A subcarrier used in the reception of TV stereophonic aural or other subchannel broadcasts.

Polarization. The direction of the electric field as radiated from the transmitting antenna.

Program related data signal. A signal, consisting of a series of pulses representing data, which is transmitted simultaneously with and directly related to the accompanying television program.

Reference black level. The level corresponding to the specified maximum excursion of the luminance signal in the black direction.

Reference white level of the luminance signal. The level corresponding to the specified maximum excursion of the luminance signal in the white direction.

Scanning. The process of analyzing successively, according to a predetermined method, the light values of picture elements constituting the total picture area.

Scanning line. A single continuous narrow strip of the picture area containing highlights, shadows, and half-tones, determined by the process of scanning.

Standard television signal. A signal which conforms to the television transmission standards.

Synchronization. The maintenance of one operation in step with another.

Television broadcast band. The frequencies in the band extending from 54 to 806 megahertz which are assignable to television broadcast stations. These frequencies are 54 to 72 megahertz (channels 2 through 4), 76 to 88 megahertz (channels 5 and 6), 174 to 216 megahertz (channels 7 through 13), and 470 to 806 megahertz (channels 14 through 69).

Television broadcast station. A station in the television broadcast band transmitting simultaneous visual and aural signals intended to be received by the general public.

Television channel. A band of frequencies 6 MHz wide in the television broadcast band and designated either by number or by the extreme lower and upper frequencies.

Television transmission standards. The standards which determine the characteristics of a television signal as radiated by a television broadcast station.

Television transmitter. The radio transmitter or transmitters for the transmission of both visual and aural signals.

Vestigial sideband transmission. A system of transmission wherein one of the generated sidebands is partially attenuated at the transmitter and radiated only in part.

Visual carrier frequency. The frequency of the carrier which is modulated by the picture information.

Visual transmitter. The radio equipment for the transmission of the visual signal only.

Visual transmitter power. The peak power output when transmitting a standard television signal.

[28 FR 13660, Dec. 14, 1963, as amended at 35 FR 5692, Apr. 8, 1970; 36 FR 5505, Mar. 24, 1971; 36 FR 17429, Aug. 31, 1971; 41 FR 56325, Dec. 28, 1976; 42 FR 20823, Apr. 22, 1977; 44 FR 36039, June 20, 1979; 47 FR 35990, Aug. 18, 1982; 49 FR 18106, Apr. 27, 1984; 49 FR 38131, Sept. 27, 1984; 49 FR 50048, Dec. 26, 1984; 50 FR 23699, June 5, 1985; 51 FR 12616, Apr. 14, 1986; 56 FR 49707, Oct. 1, 1991; 58 FR 44951, Aug. 25, 1993; 62 FR 51059, Sept. 30, 1997]

(a) Transmission standards. (1) The width of the television broadcast channel shall be 6 MHz.

(2) The visual carrier frequency shall be nominally 1.25 MHz above the lower boundary of the channel.

(3) The aural center frequency shall be 4.5 MHz higher than the visual carrier frequency.

(4) The visual transmission amplitude characteristic shall be in accordance with the chart designated as Figure 5 of §73.699: Provided, however, That for stations operating on Channel 15 through 69 and employing a transmitter with maximum peak visual power output of 1 kW or less the visual transmission amplitude characteristic may be in accordance with the chart designated as Figure 5a of §73.699.

(5) The chrominance subcarrier frequency is 63/88 times precisely 5 MHz (3.57954545 . . . MHz). The tolerance is ±10 Hz and the rate of frequency drift must not exceed 0.1 Hz per second (cycles per second squared).

(6) For monochrome and color transmissions the number of scanning lines per frame shall be 525, interlaced two to one in successive fields. The horizontal scanning frequency shall be 2/455 times the chrominance subcarrier frequency; this corresponds nominally to 15,750 Hz with an actual value of 15,734.264 ±0.044 Hz). The vertical scanning frequency is 2/525 times the horizontal scanning frequency; this corresponds nominally to 60 Hz (the actual value is 59.94 Hz). For monochrome transmissions only, the nominal values of line and field frequencies may be used.

(7) The aspect ratio of the transmitted television picture shall be 4 units horizontally to 3 units vertically.

(8) During active scanning intervals, the scene shall be scanned from left to right horizontally and from top to bottom vertically, at uniform velocities.

(9) A carrier shall be modulated within a single television channel for both picture and synchronizing signals. The two signals comprise different modulation ranges in amplitude in accordance with the following:

(i) Monochrome transmissions shall comply with synchronizing waveform specifications in Figure 7 of §73.699.

(ii) Color transmissions shall comply with the synchronizing waveform specifications in Figure 6 of §73.699.

(iii) All stations operating on Channels 2 through 14 and those stations operating on Channels 15 through 69 licensed for a peak visual transmitter output power greater than one kW shall comply with the picture transmission amplitude characteristics shown in Figure 5 of §73.699.

(iv) Stations operating on Channels 15 through 69 licensed for a peak visual transmitter output power of one kW or less shall comply with the picture transmission amplitude characteristic shown in Figure 5 or 5a of §73.699.

(10) A decrease in initial light intensity shall cause an increase in radiated power (negative transmission).

(11) The reference black level shall be represented by a definite carrier level, independent of light and shade in the picture.

(12) The blanking level shall be transmitted at 75±2.5 percent of the peak carrier level.

(13) The reference white level of the luminance signal shall be 12.5±2.5 percent of the peak carrier level.

(14) It shall be standard to employ horizontal polarization. However, circular or elliptical polarization may be employed if desired, in which case clockwise (right hand) rotation, as defined in the IEEE Standard Definition 42A65–3E2, and transmission of the horizontal and vertical components in time and space quadrature shall be used. For either omnidirectional or directional antennas the licensed effective radiated power of the vertically polarized component may not exceed the licensed effective radiated power of the horizontally polarized component. For directional antennas, the maximum effective radiated power of the vertically polarized component shall not exceed the maximum effective radiated power of the horizontally polarized component in any specified horizontal or vertical direction.

(15) The effective radiated power of the aural transmitter must not exceed 22% of the peak radiated power of the visual transmitter.

(16) The peak-to-peak variation of transmitter output within one frame of video signal due to all causes, including hum, noise, and low-frequency response, measured at both scanning synchronizing peak and blanking level, shall not exceed 5 percent of the average scanning synchronizing peak signal amplitude. This provision is subject to change but is considered the best practice under the present state of the art. It will not be enforced pending a further determination thereof.

(17) The reference black level shall be separated from the blanking level by the setup interval, which shall be 7.5±2.5 percent of the video range from blanking level to the reference white level.

(18) For monochrome transmission, the transmitter output shall vary in substantially inverse logarithmic relation to the brightness of the subject. No tolerances are set at this time. This provision is subject to change but is considered the best practice under the present state of the art. It will not be enforced pending a further determination thereof.

(19) The color picture signal shall correspond to a luminance component transmitted as amplitude modulation of the picture carrier and a simultaneous pair of chrominance components transmitted as the amplitude modulation sidebands of a pair of suppressed subcarriers in quadrature.

(20) Equation of complete color signal.

(i) The color picture signal has the following composition:

EM=EY′+[EQ′ sin (ωt+33°)+EI′ cos (ωt+33°)]

Where:

For color-difference frequencies below 500 kHz (see (iii) below), the signal can be represented by:

EM=EY′+[(1/1.14)[(1/1.78)(EB′−EY′) sin ωt+(ER′−EY′) cos ωt]]

(ii) The symbols in paragraph (a)(20)(i) of this section have the following significance:

EM is the total video voltage, corresponding to the scanning of a particular picture element, applied to the modulator of the picture transmitter.

Note: Forming of the high frequency portion of the monochrome signal in a different manner is permissible and may in fact be desirable in order to improve the sharpness on saturated colors.

EQ′ and EI′ are the amplitudes of two orthogonal components of the chrominance signal corresponding respectively to narrow-band and wide-band axes.

(iii) The equivalent bandwidth assigned prior to modulation to the color difference signals EQ′ and EI′ are as follows:

Q-channel bandwidth:

(iv) The gamma corrected voltages ER′, EG′, and EB′ are suitable for a color picture tube having primary colors with the following chromaticities in the CIE system of specification:

and having a transfer gradient (gamma exponent) of 2.2 associated with each primary color. The voltages ER′, EG′, and EB′ may be respectively of the form ER¹ /γ, EG¹/γ, and EB¹ /γ although other forms may be used with advances in the state of the art.

Note: At the present state of the art it is considered inadvisable to set a tolerance on the value of gamma and correspondingly this portion of the specification will not be enforced.

(v) The radiated chrominance subcarrier shall vanish on the reference white of the scene.

Note: The numerical values of the signal specification assume that this condition will be reproduced as CIE Illuminant C (x=0.310, y=0.316).

(vi) EY′, EQ′, EI′, and the components of these signals shall match each other in time to 0.05 µsecs.

(vii) The angles of the subcarrier measured with respect to the burst phase, when reproducing saturated primaries and their complements at 75 percent of full amplitude, shall be within ±10° and their amplitudes shall be within ±20 percent of the values specified above. The ratios of the measured amplitudes of the subcarrier to the luminance signal for the same saturated primaries and their complements shall fall between the limits of 0.8 and 1.2 of the values specified for their ratios. Closer tolerances may prove to be practicable and desirable with advance in the art.

(21) The interval beginning with line 17 and continuing through line 20 of the vertical blanking interval of each field may be used for the transmission of test signals, cue and control signals, and identification signals, subject to the conditions and restrictions set forth below. Test signals may include signals designed to check the performance of the overall transmission system or its individual components. Cue and control signals shall be related to the operation of the TV broadcast station. Identification signals may be transmitted to identify the broadcast material or its source, and the date and time of its origination. Figures 6 and 7 of §73.699 identify the numbered lines referred to in this paragraph.

(i) Modulation of the television transmitter by such signals shall be confined to the area between the reference white level and the blanking level, except where test signals include chrominance subcarrier frequencies, in which case positive excursions of chrominance components may exceed reference white, and negative excursions may extend into the synchronizing area. In no case may the modulation excursions produced by test signals extend beyond peak-of-sync, or to zero carrier level.

(ii) The use of such signals shall not result in significant degradation of the program transmission of the television broadcast station, nor produce emission outside of the frequency band occupied for normal program transmissions.

(iii) Such signals may not be transmitted during that portion of each line devoted to horizontal blanking.

(iv) Regardless of other provisions of this paragraph, after June 30, 1994, Line 19, in each field, may be used only for the transmission of the ghost-canceling reference signal described in OET Bulletin No. 68, which is available from the FCC Warehouse, 9300 East Hampton Drive, Capitol Heights, MD 20743. Notwithstanding the modulation limits contained in paragraph (a)(23)(i) of this section, the vertical interval reference signal formerly permitted on Line 19 and described in Figure 16 of §73.699, may be transmitted on any of lines 10 through 16 without specific Commission authorization, subject to the conditions contained in paragraphs (a)(21)(ii) and (a)(22)(ii) of this section.

(22)(i) Line 21, in each field, may be used for the transmission of a program-related data signal which, when decoded, provides a visual depiction of information simultaneously being presented on the aural channel (captions). Line 21, field 2 may be used for transmission of a program-related data signal which, when decoded, identifies a rating level associated with the current program. Such data signals shall conform to the format described in figure 17 of §73.699 of this chapter, and may be transmitted during all periods of regular operation. On a space available basis, line 21 field 2 may also be used for text-mode data and extended data service information.

Note: The signals on Fields 1 and 2 shall be distinct data streams, for example, to supply captions in different languages or at different reading levels.

(ii) At times when Line 21 is not being used to transmit a program related data signal, data signals which are not program related may be transmitted, Provided: the same data format is used and the information to be displayed is of a broadcast nature.

(iii) The use of Line 21 for transmission of other data signals conforming to other formats may be used subject to prior authorization by the Commission.

(iv) The data signal shall cause no significant degradation to any portion of the visual signal nor produce emissions outside the authorized television channel.

(v) Transmission of visual emergency messages pursuant to §73.1250 shall take precedence and shall be cause for interrupting transmission of data signals permitted under this paragraph.

(23) Specific scanning lines in the vertical blanking interval may be used for the purpose of transmitting telecommunications signals in accordance with §73.646, subject to certain conditions:

(i) Telecommunications may be transmitted on Lines 10–18 and 20, all of Field 2 and Field 1. Modulation level shall not exceed 70 IRE on lines 10, 11, and 12; and, 80 IRE on lines 13–18 and 20.

(ii) No observable degradation may be caused to any portion of the visual or aural signals.

(iii) Telecommunications signals must not produce emissions outside the authorized television channel bandwidth. Digital data pulses must be shaped to limit spectral energy to the nominal video baseband.

(iv) Transmission of emergency visual messages pursuant to §73.1250 must take precedence over, and shall be cause for interrupting, a service such as teletext that provides a visual depiction of information simultaneously transmitted on the aural channel.

(v) A reference pulse for a decoder associated adaptive equalizer filter designed to improve the decoding of telecommunications signals may be inserted on any portion of the vertical blanking interval authorized for data service, in accordance with the signal levels set forth in paragraph (a)(23)(i) of this section.

(vi) All lines authorized for telecommunications transmissions may be used for other purposes upon prior approval by the Commission.

(24) Licensees and permittees of TV broadcast and low power TV stations may insert non-video data into the active video portion of their TV transmission, subject to certain conditions:

(i) The active video portion of the visual signal begins with line 22 and continues through the end of each field, except it does not include that portion of each line devoted to horizontal blanking. Figures 6 and 7 of §73.699 identify the numbered line referred to in this paragraph;

(ii) Inserted non-video data may be used for the purpose of transmitting a telecommunications service in accordance with §73.646. In addition to a telecommunications service, non-video data can be used to enhance the station's broadcast program service or for purposes related to station operations. Signals relating to the operation of TV stations include, but are not limited to program or source identification, relay of broadcast materials to other stations, remote cueing and order messages, and control and telemetry signals for the transmitting system; and

(iii) A station may only use systems for inserting non-video information that have been approved in advance by the Commission. The criteria for advance approval of systems are as follows:

(A) The use of such signals shall not result in significant degradation to any portion of the visual, aural, or program-related data signals of the television broadcast station;

(B) No increase in width of the television broadcast channel (6 MHz) is permitted. Emissions outside the authorized television channel must not exceed the limitations given in §73.687(e). Interference to reception of television service either of co-channel or adjacent channel stations must not increase over that resulting from the transmission of programming without inserted data; and

(C) Where required, system receiving or decoding devices must meet the TV interface device provisions of Part 15, Subpart H of this chapter.

(iv) No protection from interference of any kind will be afforded to reception of inserted non-video data.

(v) Upon request by an authorized representative of the Commission, the licensee of a TV station transmitting encoded programming must make available a receiving decoder to the Commission to carry out its regulatory responsibilities.

(b) Subscription TV technical systems. The FCC may specify, as part of the advance approval of the technical system for transmitting encoded subscription programming, deviations from the power determination procedures, operating power levels, aural or video baseband signals, modulation levels or other characteristics of the transmitted signal as otherwise specified in this Subpart. Any decision to approve such operating deviations shall be solely at the discretion of the FCC.

(c) TV multiplex subcarrier/stereophonic aural transmission standards.

(1) The modulating signal for the main channel shall consist of the sum of the stereophonic (biphonic, quadraphonic, etc.) input signals.

(2) The instantaneous frequency of the baseband stereophonic subcarrier must at all times be within the range 15 kHz to 120 kHz. Either amplitude or frequency modulation of the stereophonic subcarrier may be used.

(3) One or more pilot subcarriers between 16 kHz and 120 kHz may be used to switch a TV receiver between the stereophonic and monophonic reception modes or to activate a stereophonic audio indicator light, and one or more subcarriers between 15 kHz and 120 kHz may be used for any other authorized purpose; except that stations employing the BTSC system of stereophonic sound transmission and audio processing may transmit a pilot subcarrier at 15,734 Hz, ±2 Hz. Other methods of multiplex subcarrier or stereophonic aural transmission systems must limit energy at 15,734 Hz, ±20 Hz, to no more than ±0.125 kHz aural carrier deviation.

(4) Aural baseband information above 120 kHz must be attenuated 40 dB referenced to 25 kHz main channel deviation of the aural carrier.

(5) For required transmitter performance, all of the requirements of §73.687(b) shall apply to the main channel, with the transmitter in the multiplex subcarrier or stereophonic aural mode.

(6) For electrical performance standards of the transmitter, the requirements of §73.687(b) apply to the main channel.

(7) Multiplex subcarrier or stereophonic aural transmission systems must be capable of producing and must not exceed ±25 kHz main channel deviation of the aural carrier.

(8) The arithmetic sum of non-multiphonic baseband signals between 15 kHz and 120 kHz must not exceed ±50 kHz deviation of the aural carrier.

(9) Total modulation of the aural carrier must not exceed ±75 kHz.

(d) Digital broadcast television transmission standard. Effective February 1, 2005, transmission of digital broadcast television (DTV) signals shall comply with the standards for such transmissions set forth in ATSC A/52: “ATSC Standard Digital Audio Compression (AC–3)” (incorporated by reference, see §73.8000), ATSC Doc. A/53B, Revision B with Amendment 1 and Amendment 2: “ATSC Digital Television Standard,” except for Section 5.1.2 (“Compression format constraints”) of Annex A (“Video Systems Characteristics”) and the phrase “see Table 3” in Section 5.1.1. Table 2 and Section 5.1.2 Table 4 (incorporated by reference, see §73.8000), and ATSC A/65B: “ATSC Program and System Information Protocol for Terrestrial Broadcast and Cable,” (Revision B) 2003 (incorporated by reference, see §73.8000). Although not incorporated by reference, licensees may also consult ATSC Doc. A/54, Guide to Use of the ATSC Digital Television Standard, (October 4, 1995), and ATSC Doc. A/69, Recommended Practice PSIP Implementation Guidelines for Broadcasters (June 25, 2002)

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13660, Dec. 14, 1963]

Editorial Note:  For Federal Register citations affecting §73.682, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO Access.

§ 73.683   Field strength contours and presumptive determination of field strength at individual locations.

(a) In the authorization of TV stations, two field strength contours are considered. These are specified as Grade A and Grade B and indicate the approximate extent of coverage over average terrain in the absence of interference from other television stations. Under actual conditions, the true coverage may vary greatly from these estimates because the terrain over any specific path is expected to be different from the average terrain on which the field strength charts were based. The required field strength, F (50,50), in dB above one micro-volt per meter (dBu) for the Grade A and Grade B contours are as follows:

(b) It should be realized that the F (50,50) curves when used for Channels 14–69 are not based on measured data at distances beyond about 48.3 kilometers (30 miles). Theory would indicate that the field strengths for Channels 14–69 should decrease more rapidly with distance beyond the horizon than for Channels 2–6, and modification of the curves for Channels 14–69 may be expected as a result of measurements to be made at a later date. For these reasons, the curves should be used with appreciation of their limitations in estimating levels of field strength. Further, the actual extent of service will usually be less than indicated by these estimates due to interference from other stations. Because of these factors, the predicted field strength contours give no assurance of service to any specific percentage of receiver locations within the distances indicated. In licensing proceedings these variations will not be considered.

(c) The field strength contours will be considered for the following purposes only:

(1) In the estimation of coverage resulting from the selection of a particular transmitter site by an applicant for a TV station.

(2) In connection with problems of coverage arising out of application of §73.3555.

(3) In determining compliance with §73.685(a) concerning the minimum field strength to be provided over the principal community to be served.

(d) For purposes of determining the eligibility of individual households for satellite retransmission of distant network signals under the copyright law provisions of 17 U.S.C. 119(d)(10)(A), field strength shall be determined by the Individual Location Longley-Rice (ILLR) propagation prediction model. Guidance for use of the ILLR model for these purposes is provided in OET Bulletin No. 72. This document is available through the Internet on the FCC Home Page at http://www.fcc.gov.

(e) In the case of measurements to determine the eligibility of individual households to receive satellite retransmission of distant network signals under the copyright law provisions of 17 U.S.C. 119(d)(10), if a satellite carrier and the network station or stations asserting that the retransmission of a signal of a distant network station is prohibited are unable to agree on a person to conduct the test, the American Radio Relay League, Inc., 225 Main Street, Newington, CT 06111–1494, shall designate the person or organization to conduct measurements based on the technical qualifications and independence of proposed testers. The satellite carrier and network station shall propose testers and provide their qualifications in writing to the American Radio Relay League (ARRL). Individuals may also volunteer themselves as testers by submitting their qualifications to the ARRL. The ARRL can be reached by telephone at 860–594–0200, or email at [email protected].

(f) A satellite carrier is exempt from the verification requirements of 47 U.S.C. 339(c)(4)(A) with respect to a test requested by a satellite subscriber to whom the retransmission of the signals of local broadcast stations is available under 47 U.S.C. 338 from such carrier. The definitions of satellite carrier, subscriber, and local market contained in 47 CFR 76.66(a) apply to this paragraph (f).

[44 FR 36039, June 20, 1979, as amended at 47 FR 35990, Aug. 18, 1982; 50 FR 23699, June 5, 1985; 50 FR 32416, Aug. 12, 1985; 65 FR 36641, June 9, 2000; 70 FR 21670, Apr. 27, 2005]

(a) All predictions of coverage made pursuant to this section shall be made without regard to interference and shall be made only on the basis of estimated field strengths. The peak power of the visual signal is used in making predictions of coverage.

(b) Predictions of coverage shall be made only for the same purposes as relate to the use of field strength contours as specified in §73.683(c).

(c) In predicting the distance to the field strength contours, the F (50,50) field strength charts (Figures 9 and 10 of §73.699) shall be used. If the 50% field strength is defined as that value exceeded for 50% of the time, these F (50,50) charts give the estimated 50% field strengths exceeded at 50% of the locations in dB above 1 uV/m. The charts are based on an effective power of 1 kW radiated form a half-wave dipole in free space, which produces an unattenuated field strength at 1.61 kilometers (1 mile) of about 103 dB above 1 uV/m. To use the charts to predict the distance to a given contour, the following procedure is used: Convert the effective radiated power in kilowatts for the appropriate azimuth into decibel value referenced to 1 kW (dBu). If necessary, convert the selected contour to the decibel value (dBu) above 1 microvolt per meter (1 uV/m). Subtract the power value in dBk from the contour value in dBu. Note that for power less than 1 kW, the difference value will be greater than the contour value because the power in dBk is negative. Locate the difference value obtained on the vertical scale at the left edge of the chart. Follow the horizontal line for that value into the chart to the point of intersection with the vertical line above the height of the antenna above average terrain for the appropriate azimuth located on the scale at the bottom of the chart. If the point of intersection does not fall exactly on a distance curve, interpolate between the distance curves below and above the intersection point. The distance values for the curves are located along the right edge of the chart.

(1) In predicting the distance to the Grade A and Grade B field strength contours, the effective radiated power to be used is that radiated at the vertical angle corresponding to the depression angle between the transmitting antenna center of radiation and the radio horizon as determined individually for each azimuthal direction concerned. The depression angle is based on the difference in elevation of the antenna center of radiation above the average terrain and the radio horizon, assuming a smooth sperical earth with a radius of 8,495.5 kilometers (5,280 miles) and shall be determined by the following equation:

A = 0.0277√ H

Where:

This formula is empirically derived for the limited purpose specified here. Its use for any other purpose may be inappropriate.

(2) In case where the relative field strength at the depression angle determined by the above formula is 90% or more of the maximum field strength developed in the vertical plane containing the pertaining radial, the maximum radiation shall be used.

(3) In predicting field strengths for other than the Grade A and Grade B contours, the effective radiated power to be used is to be based on the appropriate antenna vertical plane radiation pattern for the azimuthal direction concerned.

(4) Applicants for new TV stations or changes in the facilities of existing TV stations must submit to the FCC a showing as to the location of their stations' or proposed stations' predicted Grade A and Grade B contours, determined in accordance with §73.684. This showing is to include maps showing these contours, except where applicants have previously submitted material to the FCC containing such information and it is found upon careful examination that the contour locations indicated therein would not change, on any radial, when the locations are determined under this Section. In the latter cases, a statement by a qualified engineer to this effect will satisfy this requirement and no contour maps need be submitted.

(d) The antenna height to be used with these charts is the height of the radiation center of the antenna above the average terrain along the radial in question. In determining the average elevation of the terrain, the elevations between 3.2–16.1 kilometers (2–10 miles) from the antenna site are employed. Profile graphs shall be drawn for 8 radials beginning at the antenna site and extending 16.1 kilometers (10 miles) therefrom. The radials should be drawn for each 45 degrees of azimuth starting with the True North. At least one radial must include the principal community to be served even though such community may be more than 16.1 kilometers (10 miles) from the antenna site. However, in the event none of the evenly spaced radials include the principal community to be served and one or more such radials are drawn in addition to the 8 evenly spaced radials, such additional radials shall not be employed in computing the antenna height above average terrain. Where the 3.2–16.1 kilometers (2–10 mile) portion of a radial extends in whole or in part over large bodies of water as specified in paragraph (e) of this section or extends over foreign territory but the Grade B strength contour encompasses land area within the United States beyond the 16.1 kilometers (10 mile) portion of the radial, the entire 3.2–16.1 kilometers (2–10 mile) portion of the radial shall be included in the computation of antenna height above average terrian. However, where the Grade B contour does not so encompass United States land area and (1) the entire 3.2–16.1 kilometers (2–10 mile) portion of the radial extends over large bodies of water of foreign territory, such radial shall be completely omitted from the computation of antenna height above average terrain, and (2) where a part of the 3.2–16.1 kilometers (2–10 mile) portion of a radial extends over large bodies of water or over foreign territory, only that part of the radial extending from the 3.2 kilometer (2 mile) sector to the outermost portion of land area within the United States covered by the radial shall be employed in the computation of antenna height above average terrian. The profile graph for each radial should be plotted by contour intervals of from 12.2–30.5 meters (40–100 feet) and, where the data permits, at least 50 points of elevation (generally uniformly spaced) should be used for each radial. In instances of very rugged terrain where the use of contour intervals of 30.5 meters (100 feet) would result in several points in a short distance, 61.0–122.0 meter (200–400 foot) contour intervals may be used for such distances. On the other hand, where the terrain is uniform or gently sloping the smallest contour interval indicated on the topograhic may (see paragraph (g) of this section) should be used, although only relatively few points may be available. The profile graphs should indicate the topography accurately for each radial, and the graphs should be plotted with the distance in kilometers as the abscissa and the elevation in meters above mean sea level as the ordinate. The profile graphs should indicate the source of the topographical data employed. The graph should also show the elevation of the center of the radiating system. The graph may be plotted either on rectangular coordinate paper or on special paper which shows the curvature of the earth. It is not necessary to take the curvature of the earth into consideration in this procedure, as this factor is taken care of in the charts showing signal strengths. The average elevation of the 12.9 kilometer (8 miles) distance between 3.2–16.1 kilometers (2–10 miles) from the antenna site should then be determined from the profile graph for each radial. This may be obtained by averaging a large number of equally spaced points, by using a planimeter, or by obtaining the median elevation (that exceeded for 50% of the distance) in sectors and averaging those values.

Note: The Commission will, upon a proper showing by an existing station that the application of this rule will result in an unreasonable power reduction in relation to other stations in close proximity, consider requests for adjustment in power on the basis of a common average terrain figure for the stations in question as determined by the FCC.

(e) In instance where it is desired to determine the area in square kilometers within the Grade A and Grade B field strength contours, the area may be determined from the coverage map by planimeter or other approximate means; in computing such areas, exclued (1) areas beyond the borders of the United States, and (2) large bodies of water, such as ocean areas, gulfs sounds, bays, large lakes, etc., but not rivers.

(f) In cases where terrain in one or more directions from the antenna site departs widely from the average elevation of the 3.2 to 16.1 kilometers (2 to 10 mile) sector, the prediction method may indicate contour distances that are different from what may be expected in practice. For example, a mountain ridge may indicate the practical limit of service although the prediction method may indicate otherwise. In such case the prediction method should be followed, but a supplemental showing may be made concerning the contour distances as determined by other means. Such supplemental showing should describe the procedure employed and should include sample calculations. Maps of predicted coverage should include both the coverage as predicted by the regular method and as predicted by a supplemental method. When measurements of area are required, these should include the area obtained by the regular predicted method and the area obtained by the supplemental method. In directions where the terrain is such that negative antenna heights or heights below 30.5 meters (100 feet) for the 3.2 to 16.1 kilometers (2 to 10 mile) sector are obtained, an assumed height of 30.5 meters (100 feet) shall be used for the prediction of coverage. However, where the actual contour distances are critical factors, a supplemental showing of expected coverage must be included together with a description of the method employed in predicting such coverage. In special cases, the Commission may require additional information as to terrain and coverage.

(g) In the preparation of the profile graph previously described, and in determining the location and height above sea level of the antenna site, the elevation or contour intervals shall be taken from the United States Geological Survey Topographic Quadrangle Maps, United States Army Corps of Engineers' maps or Tennessee Valley Authority maps, whichever is the latest, for all areas for which such maps are available. If such maps are not published for the area in question, the next best topographic information should be used. Topographic data may sometimes be obtained from State and Municipal agencies. Data from Sectional Aeronautical Charts (including bench marks) or railroad depot elevations and highway elevations from road maps may be used where no better information is available. In cases where limited topographic data is available, use may be made of an altimeter in a car driven along roads extending generally radially from the transmitter site. Ordinarily the Commission will not require the submission of topographical maps for areas beyond 24.1 kilometers (15 miles) from the antenna site, but the maps must include the principal community to be served. If it appears necessary, additional data may be requested. United States Geological Survey Topographic Quadrangle Maps may be obtained from the United States Geological Survey, Department of the Interior, Washington, DC 20240. Sectional Aeronautical Charts are available from the United States Coast and Geodetic Survey, Department of Commerce, Washington, DC 20235. In lieu of maps, the average terrain elevation may be computer generated, except in the cases of dispute, using elevations from a 30 second point or better topographic data file. The file must be identified and the data processed for intermediate points along each radial using linear interpolation techniques. The height above mean sea level of the antenna site must be obtained manually using appropriate topographic maps.

(h) The effect of terrain roughness on the predicted field strength of a signal at points distant from a television broadcast station is assumed to depend on the magnitude of a terrain roughness factor (Δ h) which, for a specific propagation path, is determined by the characteristics of a segment of the terrain profile for that path 40.2 kilometers (25 miles) in length, located between 9.7 and 49.9 kilometers (6 and 31 miles) from the transmitter. The terrain roughness factor has a value equal to the difference, in meters, between elevations exceeded by all points on the profile for 10 percent and 90 percent, respectively, of the length of the profile segment (see §73.699, Fig. 10d).

(i) If the lowest field strength value of interest is initially predicted to occur over a particular propagation path at a distance which is less than 49.9 kilometers (31 miles) from the transmitter, the terrain profile segment used in the determination of the terrain roughness factor over that path shall be that included between points 9.7 kilometers (6 miles) from the transmitter and such lesser distance. No terrain roughness correction need be applied when all field strength values of interest are predicted to occur 9.7 kilometers (6 miles) or less from the transmitter.

(j) Profile segments prepared for terrain roughness factor determinations should be plotted in rectangular coordinates, with no less than 50 points evenly spaced within the segment, using data obtained from topographic maps, if available, with contour intervals of 15.2 meters (50 feet), or less.

(k) The field strength charts (§73.699, Figs. 9–10c) were developed assuming a terrain roughness factor of 50 meters, which is considered to be representative of average terrain in the United States. Where the roughness factor for a particular propagation path is found to depart appreciably from this value, a terrain roughness correction (ΔF) should be applied to field strength values along this path as predicted with the use of these charts. The magnitude and sign of this correction, for any value of Δh, may be determined from a chart included in §73.699 as Figure 10e, with linear interpolation as necessary, for the frequency of the UHF signal under consideration.

(l) Alternatively, the terrain roughness correction may be computed using the following formula:

ΔF=C−0.03(Δh)(1+f/300)

Where:

[28 FR 13660, Dec. 13, 1963, as amended at 40 FR 27683, July 1, 1975; 44 FR 36039, June 20, 1979; 48 FR 44807, Sept. 30, 1983; 50 FR 23699, June 5, 1985; 51 FR 26251, July 22, 1986; 52 FR 36879, Oct. 1, 1987]

Effective Date Note:  At 42 FR 25736, May 19, 1977, in §73.684, paragraphs (k) and (l) were stayed indefinitely.

§ 73.685   Transmitter location and antenna system.

(a) The transmitter location shall be chosen so that, on the basis of the effective radiated power and antenna height above average terrain employed, the following minimum field strength in dB above one uV/m will be provided over the entire principal community to be served:

(b) Location of the antenna at a point of high elevation is necessary to reduce to a minimum the shadow effect on propagation due to hills and buildings which may reduce materially the strength of the station's signals. In general, the transmitting antenna of a station should be located at the most central point at the highest elevation available. To provide the best degree of service to an area, it is usually preferable to use a high antenna rather than a low antenna with increased transmitter power. The location should be so chosen that line-of-sight can be obtained from the antenna over the principal community to be served; in no event should there be a major obstruction in this path. The antenna must be constructed so that it is as clear as possible of surrounding buildings or objects that would cause shadow problems. It is recognized that topography, shape of the desired service area, and population distribution may make the choice of a transmitter location difficult. In such cases, consideration may be given to the use of a directional antenna system, although it is generally preferable to choose a site where a nondirectional antenna may be employed.

(c) In cases of questionable antenna locations it is desirable to conduct propagation tests to indicate the field strength expected in the principal community to be served and in other areas, particularly where severe shadow problems may be expected. In considering applications proposing the use of such locations, the Commission may require site tests to be made. Such tests should be made in accordance with the measurement procedure in §73.686, and full data thereon must be supplied to the Commission. Test transmitters should employ an antenna having a height as close as possible to the proposed antenna height, using a balloon or other support if necessary and feasible. Information concerning the authorization of site tests may be obtained from the Commission upon request.

(d) Present information is not sufficiently complete to establish “blanket areas” of television broadcast stations. A “blanket area” is that area adjacent to a transmitter in which the reception of other stations is subject to interference due to the strong signal from this station. The authorization of station construction in areas where blanketing is found to be excessive will be on the basis that the applicant will assume full responsibility for the adjustment of reasonable complaints arising from excessively strong signals of the applicant's station or take other corrective action.

(e) An antenna designed or altered to produce a noncircular radiation pattern in the horizontal plane is considered to be a directional antenna. Antennas purposely installed in such a manner as to result in the mechanical beam tilting of the major vertical radiation lobe are included in this category. Directional antennas may be employed for the purpose of improving service upon an appropriate showing of need. Stations operating on Channels 2–13 will not be permitted to employ a directional antenna having a ratio of maximum to minimum radiation in the horizontal plane in excess of 10 dB. Stations operating on Channels 14–69 with transmitters delivering a peak visual power output of more than 1 kW may employ directive transmitting antennas with a maximum to minimum radiation in the horizontal plane of not more than 15 dB. Stations operating on Channels 14–69 and employing transmitters delivering a peak visual power output of 1 kW or less are not limited as to the ratio of maximum to minimum radiation.

(f) Applications proposing the use of directional antenna systems must be accompanied by the following:

(1) Complete description of the proposed antenna system, including the manufacturer and model number of the proposed directional antenna.

(2) Relative field horizontal plane pattern (horizontal polarization only) of the proposed directional antenna. A value of 1.0 should be used for the maximum radiation. The plot of the pattern should be oriented so that 0° corresponds to true North. Where mechanical beam tilt is intended, the amount of tilt in degrees of the antenna vertical axis and the orientation of the downward tilt with respect to true North must be specified, and the horizontal plane pattern must reflect the use of mechanical beam tilt.

(3) A tabulation of the relative field pattern required in paragraph (b)(2), of this section. The tabulation should use the same zero degree reference as the plotted pattern, and be tabulated at least every 10°. In addition, tabulated values of all maxima and minima, with their corresponding azimuths, should be submitted.

(4) Horizontal and vertical plane radiation patterns showing the effective radiated power, in dBk, for each direction. Sufficient vertical plane patterns must be included to indicate clearly the radiation characteristics of the antenna above and below the horizontal plane. In cases where the angles at which the maximum vertical radiation varies with azimuth, a separate vertical radiation pattern must be provided for each pertinent radial direction.

(5) All horizontal plane patterns must be plotted to the largest scale possible on unglazed letter-size polar coordinate paper (main engraving approximately 18 cm × 25 cm (7 inches × 10 inches)) using only scale divisions and subdivisions of 1, 2, 2.5 or 5 times 10-nth. All vertical plane patterns must be plotted on unglazed letter-size rectangular coordinate paper. Values of field strength on any pattern less than 10% of the maximum field strength plotted on that pattern must be shown on an enlarged scale.

(6) The horizontal and vertical plane patterns that are required are the patterns for the complete directional antenna system. In the case of a composite antenna composed of two or more individual antennas, this means that the patterns for the composite antenna, not the patterns for each of the individual antennas, must be submitted.

(g) Applications proposing the use of television broadcast antennas within 61.0 meters (200 feet) of other television broadcast antennas operating on a channel within 20 percent in frequency of the proposed channel, or proposing the use of television broadcast antennas on Channels 5 or 6 within 61.0 meters (200 feet) of FM broadcast antennas, must include a showing as to the expected effect, if any, of such proximate operation.

(h) Where a TV licensee or permittee proposes to mount an antenna on an AM antenna tower, or locate within 3.2 km of an AM antenna tower, the TV licensee or permittee must comply with §73.1692.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13660, Dec. 14, 1963, as amended at 35 FR 5693, Apr. 8, 1970; 40 FR 25461, June 16, 1975; 43 FR 53740, Nov. 17, 1978; 44 FR 22740, Apr. 17, 1979; 45 FR 26065, Apr. 17, 1980; 47 FR 35990, Aug. 18, 1982; 48 FR 21486, May 12, 1983; 50 FR 23701, June 5, 1985; 58 FR 44951, Aug. 25, 1993; 62 FR 51059, Sept. 30, 1997]

(a) Except as provided for in §73.612, television broadcast stations shall not be protected from any type of interference or propagation effect. Persons desiring to submit testimony, evidence or data to the Commission for the purpose of showing that the technical standards contained in this subpart do not properly reflect the levels of any given type of interference or propagation effect may do so only in appropriate rulemaking proceedings concerning the amendment of such technical standards. Persons making field strength measurements for formal submission to the Commission in rulemaking proceedings, or making such measurements upon the request of the Commission, shall follow the procedure for making and reporting such measurements outlined in paragraph (b) of this section. In instances where a showing of the measured level of a signal prevailing over a specific community is appropriate, the procedure for making and reporting field strength measurements for this purpose is set forth in paragraph (c) of this section.

(b) Collection of field strength data for propagation analysis—(1) Preparation for measurements. (i) On large scale topographic maps, eight or more radials are drawn from the transmitter location to the maximum distance at which measurements are to be made, with the angles included between adjacent radials of approximately equal size. Radials should be oriented so as to traverse representative types of terrain. The specific number of radials and their orientation should be such as to accomplish this objective.

(ii) At a point exactly 16.1 kilometers (10 miles) from the transmitter, each radial is marked, and at greater distances at successive 3.2 kilometer (2 mile) intervals. Where measurements are to be conducted at UHF, or over extremely rugged terrain, shorter intervals may be employed, but all such intervals shall be of equal length. Accessible roads intersecting each radial as nearly as possible at each 3.2 kilometer (2 mile) marker are selected. These intersections are the points on the radial at which measurements are to be made, and are referred to subsequently as measuring locations. The elevation of each measuring location should approach the elevation at the corresponding 3.2 kilometer (2 mile) marker as nearly as possible.

(2) Measurement procedure. The field strength of the visual carrier shall be measured with a voltmeter capable of indicating accurately the peak amplitude of the synchronizing signal. All measurements shall be made utilizing a receiving antenna designed for reception of the horizontally polarized signal component, elevated 9.1 meters (30 feet) above the roadbed. At each measuring location, the following procedure shall be employed.

(i) The instrument calibration is checked.

(ii) The antenna is elevated to a height of 30 feet.

(iii) The receiving antenna is rotated to determine if the strongest signal is arriving from the direction of the transmitter.

(iv) The antenna is oriented so that the sector of its response pattern over which maximum gain is realized is in the direction of the transmitter.

(v) A mobile run of at least 30.5 meters (100 feet) is made, which is centered on the intersection of the radial and the road, and the measured field strength is continuously recorded on a chart recorder over the length of the run.

(vi) The actual measuring location is marked exactly on the topographic map, and a written record, keyed to the specific location, is made of all factors which may affect the recorded field, such as topography, height and types of vegetation, buildings, obstacles, weather, and other local features.

(vii) If, during the test conducted as described in paragraph (b)(2)(iii) of this section, the strongest signal is found to come from a direction other than from the transmitter, after the mobile run prescribed in paragraph (b)(2)(v) of this section is concluded, additional measurements shall be made in a “cluster” of at least five fixed points. At each such point, the field strengths with the antenna oriented toward the transmitter, and with the antenna oriented so as to receive the strongest field, are measured and recorded. Generally, all points should be within 61.0 meters (200 feet) of the center point of the mobile run.

(viii) If overhead obstacles preclude a mobile run of at leat 30.5 meters (100 feet), a “cluster” of five spot measurements may be made in lieu of this run. The first measurement in the cluster is identified. Generally, the locations for other measurements shall be within 61.0 meters (200 feet) of the location of the first.

(3) Method of reporting measurements. A report of measurements to the Commission shall be submitted in affidavit form, in triplicate, and should contain the following information:

(i) Tables of field strength measurements, which, for each measuring location, set forth the following data:

(A) Distance from the transmitting antenna.

(B) Ground elevation at measuring location.

(C) Date, time of day, and weather.

(D) Median field in dBu for 0 dBk, for mobile run or for cluster, as well as maximum and minimum measured field strengths.

(E) Notes describing each measuring location.

(ii) U.S. Geological Survey topographic maps, on which is shown the exact location at which each measurement was made. The original plots shall be made on maps of the largest available scale. Copies may be reduced in size for convenient submission to the Commission, but not to the extent that important detail is lost. The original maps shall be made available, if requested. If a large number of maps is involved, an index map should be submitted.

(iii) All information necessary to determine the pertinent characteristics of the transmitting installation, including frequency, geographical coordinates of antenna site, rated and actual power output of transmitter, measured transmission line loss, antenna power gain, height of antenna above ground, above mean sea level, and above average terrain. The effective radiated power should be computed, and horizontal and vertical plane patterns of the transmitting antenna should be submitted.

(iv) A list of calibrated equipment used in the field strength survey, which, for each instrument, specifies its manufacturer, type, serial number and rated accuracy, and the date of its most recent calibration by the manufacturer, or by a laboratory. Complete details of any instrument not of standard manufacture shall be submitted.

(v) A detailed description of the calibration of the measuring equipment, including field strength meters, measuring antenna, and connecting cable.

(vi) Terrain profiles in each direction in which measurements were made, drawn on curved earth paper for equivalent 4/3 earth radius, of the largest available scale.

(c) Collection of field strength data to determine television service in specific communities—(1) Preparation for measurement. (i) The population (P) of the community, and its suburbs, if any, is determined by reference to an appropriate source, e.g., the 1970 U.S. Census tables of population of cities and urbanized areas.

(ii) The number of locations at which measurements are to be made shall be at least 15, and shall be approximately equal to 0.1 (P) 1/2, if this product is a number greater than 15.

(iii) A rectangular grid, of such size and shape as to encompass the boundaries of the community is drawn on an accurate map of the community. The number of line intersections on the grid included within the boundaries of the community shall be at least equal to the required number of measuring locations. The position of each intersection on the community map determines the location at which a measurement shall be made.

(2) Measurement procedure. The field strength of the visual carrier shall be measured, with a voltmeter capable of indicating accurately the peak amplitude of the synchronizing signal. All measurements shall be made utilizing a receiving antenna designed for reception of the horizontally polarized signal component, elevated 9.1 meter (30 feet) above street level.

(i) Each measuring location shall be chosen as close as feasible to a point indicated on the map, as previously prepared, and at as nearly the same elevation as that point as possible.

(ii) At each measuring location, after equipment calibration and elevation of the antenna, a check is made to determine whether the strongest signal arrives from a direction other than from the transmitter.

(iii) At 20 percent or more of the measuring locations, mobile runs, as described in paragraph (b)(2) of this section shall be made, with no less than three such mobile runs in any case. The points at which mobile measurements are made shall be well separated. Spot measurements may be made at other measuring points.

(iv) Each actual measuring location is marked exactly on the map of the community, and suitably keyed. A written record shall be maintained, describing, for each location, factors which may affect the recorded field, such as the approximate time of measurement, weather, topography, overhead wiring, heights and types of vegetation, buildings and other structures. The orientation, with respect to the measuring location shall be indicated of objects of such shape and size as to be capable of causing shadows or reflections. If the strongest signal received was found to arrive from a direction other than that of the transmitter, this fact shall be recorded.

(3) Method of reporting measurements. A report of measurements to the Commission shall be submitted in affidavit form, in triplicate, and should contain the following information:

(i) A map of the community showing each actual measuring location, specifically identifying the points at which mobile runs were made.

(ii) A table keyed to the above map, showing the field strength at each measuring point, reduced to dBu for the actual effective radiated power of the station. Weather, date, and time of each measurement shall be indicated.

(iii) Notes describing each measuring location.

(iv) A topographic map of the largest available scale on which are marked the community and the transmitter site of the station whose signals have been measured, which includes all areas on or near the direct path of signal propagation.

(v) Computations of the mean and standard deviation of all measured field strengths, or a graph on which the distribution of measured field strength values is plotted.

(vi) A list of calibrated equipment used for the measurements, which for each instrument, specifies its manufacturer, type, serial number and rated accuracy, and the date of its most recent calibration by the manufacturer, or by a laboratory. Complete details of any instrument not of standard manufacture shall be submitted.

(vii) A detailed description of the procedure employed in the calibration of the measuring equipment, including field strength meters measuring antenna, and connecting cable.

(d) Collection of field strength data to determine television signal intensity at an individual location—cluster measurements—(1) Preparation for measurements—(i) Testing antenna. The test antenna shall be either a standard half-wave dipole tuned to the visual carrier frequency of the channel being measured or a gain antenna, provided its antenna factor for the channel(s) under test has been determined. Use the antenna factor supplied by the antenna manufacturer as determined on an antenna range.

(ii) Testing locations. At the location, choose a minimum of five locations as close as possible to the specific site where the site's receiving antenna is located. If there is no receiving antenna at the site, choose the minimum of five locations as close as possible to a reasonable and likely spot for the antenna. The locations shall be at least three meters apart, enough so that the testing is practical. If possible, the first testing point should be chosen as the center point of a square whose corners are the four other locations. Calculate the median of the five measurements (in units of dBu) and report it as the measurement result.

(iii) Multiple signals. If more than one signal is being measured (i.e., signals from different transmitters), use the same locations to measure each signal.

(2) Measurement procedure. Measurements shall be made in accordance with good engineering practice and in accordance with this section of the Rules. At each measuring location, the following procedure shall be employed:

(i) Testing equipment. Measure the field strength of the visual carrier with a calibrated instrument with an i.f. bandwidth of at least 200 kHz, but no greater than one megahertz (1,000 kHz). Perform an on-site calibration of the instrument in accordance with the manufacturer's specifications. The instrument must accurately indicate the peak amplitude of the synchronizing signal. Take all measurements with a horizontally polarized antenna. Use a shielded transmission line between the testing antenna and the field strength meter. Match the antenna impedance to the transmission line at all frequencies measured, and, if using an unbalanced line, employ a suitable balun. Take account of the transmission line loss for each frequency being measured.

(ii) Weather. Do not take measurements in inclement weather or when major weather fronts are moving through the measurement area.

(iii) Antenna elevation. When field strength is being measured for a one-story building, elevate the testing antenna to 6.1 meters (20 feet) above the ground. In situations where the field strength is being measured for a building taller than one-story, elevate the testing antenna 9.1 meters (30 feet) above the ground.

(iv) Antenna orientation. Orient the testing antenna in the direction which maximizes the value of field strength for the signal being measured. If more than one station's signal is being measured, orient the testing antenna separately for each station.

(3) Written record shall be made and shall include at least the following:

(i) A list of calibrated equipment used in the field strength survey, which for each instrument, specifies the manufacturer, type, serial number and rated accuracy, and the date of the most recent calibration by the manufacturer or by a laboratory. Include complete details of any instrument not of standard manufacture.

(ii) A detailed description of the calibration of the measuring equipment, including field strength meters, measuring antenna, and connecting cable.

(iii) For each spot at the measuring site, all factors which may affect the recorded field, such as topography, height and types of vegetation, buildings, obstacles, weather, and other local features.

(iv) A description of where the cluster measurements were made.

(v) Time and date of the measurements and signature of the person making the measurements.

(vi) For each channel being measured, a list of the measured value of field strength (in units of dBu and after adjustment for line loss and antenna factor) of the five readings made during the cluster measurement process, with the median value highlighted.

[40 FR 27683, July 1, 1975, as amended at 50 FR 23701, June 5, 1985; 64 FR 7127, Feb. 12, 1999; 64 FR 73433, Dec. 30, 1999]

(a) Visual transmitter. (1) The field strength or voltage of the lower sideband, as radiated or dissipated and measured as described in paragraph (a)(2) of this section, shall not be greater than −20 dB for a modulating frequency of 1.25 MHz or greater and in addition, for color, shall not be greater than −42 dB for a modulating frequency of 3.579545 MHz (the color subcarrier frequency). For both monochrome and color, the field strength or voltage of the upper sideband as radiated or dissipated and measured as described in paragraph (a)(2) of this section shall not be greater than −20 dB for a modulating frequency of 4.75 MHz or greater. For stations operating on Channels 15–69 and employing a transmitter delivering maximum peak visual power output of 1 kW or less, the field strength or voltage of the upper and lower sidebands, as radiated or dissipated and measured as described in paragraph (a)(2) of this section, shall depart from the visual amplitude characteristic (Figure 5a of §73.699) by no more than the following amounts:

−2 dB at 0.5 MHz below visual carrier frequency;

The field strength or voltage of the upper and lower sidebands, as radiated or dissipated and measured as described in paragraph (a)(2) of this section, shall not exceed a level of −20 dB for a modulating frequency of 4.75 MHz or greater. If interference to the reception of other stations is caused by out-of-channel lower sideband emission, the technical requirements applicable to stations operating on Channels 2–13 shall be met.

(2) The attenuation characteristics of a visual transmitter shall be measured by application of a modulating signal to the transmitter input terminals in place of the normal composite television video signal. The signal applied shall be a composite signal composed of a synchronizing signal to establish peak output voltage plus a variable frequency sine wave voltage occupying the interval between synchronizing pulses. (The “synchronizing signal” referred to in this section means either a standard synchronizing wave form or any pulse that will properly set the peak.) The axis of the sine wave in the composite signal observed in the output monitor shall be maintained at an amplitude 0.5 of the voltage at synchronizing peaks. The amplitude of the sine wave input shall be held at a constant value. This constant value should be such that at no modulating frequency does the maximum excursion of the sine wave, observed in the composite output signal monitor, exceed the value 0.75 of peak output voltage. The amplitude of the 200 kHz sideband shall be measured and designated zero dB as a basis for comparison. The modulation signal frequency shall then be varied over the desired range and the field strength or signal voltage of the corresponding sidebands measured. As an alternate method of measuring, in those cases in which the automatic d-c insertion can be replaced by manual control, the above characteristic may be taken by the use of a video sweep generator and without the use of pedestal synchronizing pulses. The d-c level shall be set for midcharacteristic operation.

(3) A sine wave, introduced at those terminals of the transmitter which are normally fed the composite color picture signal, shall produce a radiated signal having an envelope delay, relative to the average envelope delay between 0.05 and 0.20 MHz, of zero microseconds up to a frequency of 3.0 MHz; and then linearly decreasing to 4.18 MHz so as to be equal to −0.17 µsecs at 3.58 MHz. The tolerance on the envelope delay shall be ±0.05 µsecs at 3.58 MHz. The tolerance shall increase linearly to ±0.1 µsec down to 2.1 MHz, and remain at ±0.1 µsec down to 0.2 MHz. (Tolerances for the interval of 0.0 to 0.2 MHz are not specified at the present time.) The tolerance shall also increase linearly to ±0.1 µsec at 4.18 MHz.

(4) The radio frequency signal, as radiated, shall have an envelope as would be produced by a modulating signal in conformity with §73.682 and Figure 6 or 7 of §73.699, as modified by vestigial sideband operation specified in Figure 5 of §73.699. For stations operating on Channels 15–69 the radio frequency signal as radiated, shall have an envelope as would be produced by a modulating signal in conformity with §73.682 and Figure 6 or 7 of §73.699.

(5) The time interval between the leading edges of successive horizontal pulses shall vary less than one half of one percent of the average interval. However, for color transmissions, §73.682(a) (5) and (6) shall be controlling.

(6) The rate of change of the frequency of recurrence of the leading edges of the horizontal synchronizing signals shall be not greater than 0.15 percent per second, the frequency to be determined by an averaging process carried out over a period of not less than 20, nor more than 100 lines, such lines not to include any portion of the blanking interval. However, for color transmissions, §73.682(a) (5) and (6) shall be controlling.

(b) Aural transmitter. (1) Pre-emphasis shall be employed as closely as practicable in accordance with the impedance-frequency characteristic of a series inductance-resistance network having a time constant of 75 microseconds. (See upper curve of Figure 12 §73.699.)

(2) If a limiting or compression amplifier is employed, precaution should be maintained in its connection in the circuit due to the use of pre-emphasis in the transmitting system.

(3) Aural modulation levels are specified in §73.1570.

(c) Requirements applicable to both visual and aural transmitters. (1) Automatic means shall be provided in the visual transmitter to maintain the carrier frequency within ±1 kHz of the authorized frequency; automatic means shall be provided in the aural transmitter to maintain the carrier frequency 4.5 MHz above the actual visual carrier frequency within ±1 kHz.

(2) The transmitters shall be equipped with suitable indicating instruments for the determination of operating power and with other instruments necessary for proper adjustment, operation, and maintenance of the equipment.

(3) Adequate provision shall be made for varying the output power of the transmitters to compensate for excessive variations in line voltage or for other factors affecting the output power.

(4) Adequate provisions shall be provided in all component parts to avoid overheating at the rated maximum output powers.

(d) The construction, installation, and operation of broadcast equipment is expected to conform with all applicable local, state, and federally imposed safety regulations and standards, enforcement of which is the responsibility of the issuing regulatory agency.

(e) Operation. (1) Spurious emissions, including radio frequency harmonics, shall be maintained at as low a level as the state of the art permits. As measured at the output terminals of the transmitter (including harmonic filters, if required) all emissions removed in frequency in excess of 3 MHz above or below the respective channel edge shall be attenuated no less than 60 dB. below the visual transmitted power. (The 60 dB. value for television transmitters specified in this rule should be considered as a temporary requirement which may be increased at a later date, especially when more higher-powered equipment is utilized. Stations should, therefore, give consideration to the installation of equipment with greater attenuation than 60 dB.) In the event of interference caused to any service greater attenuation will be required.

(2) If a limiting or compression amplifier is used in conjunction with the aural transmitter, due operating precautions should be maintained because of pre-emphasis in the transmitting system.

(3) TV broadcast stations operating on Channel 14 and Channel 69 must take special precautions to avoid interference to adjacent spectrum land mobile radio service facilities. Where a TV station is authorized and operating prior to the authorization and operation of the land mobile facility, a Channel 14 station must attenuate its emissions within the frequency range 467 to 470 MHz and a Channel 69 station must attentuate its emissions within the frequency range 806 to 809 MHz if necessary to permit reasonable use of the adjacent frequencies by land mobile licensees.

(4) The requirements listed below apply to permittees authorized to construct a new station on TV Channel 14 or TV Channel 69, and to licensees authorized to change the channel of an existing station to Channel 14 or to Channel 69, to increase effective radiated power (ERP) (including any change in directional antenna characteristics that results in an increase in ERP in any direction), or to change the transmitting location of an existing station.

(i) For the purposes of this paragraph, a protected land mobile facility is a receiver that is intended to receive transmissions from licensed land mobile stations within the frequency band below 470 MHz (as relates to Channel 14) or above 806 MHz (as relates to Channel 69), and is associated with one or more land mobile stations for which a license has been issued by the Commission, or a proper application has been received by the Commission prior to the date of the filing of the TV construction permit application. However, a land mobile facility will not be protected if it is proposed in an application that is denied or dismissed and that action is no longer subject to Commission review. Further, if the land mobile station is not operating when the TV facility commences operation and it does not commence operation within the time permitted by its authorization in accordance with part 90 of this chapter, it will not be protected.

(ii) A TV permittee must take steps before construction to identify potential interference to normal land mobile operation that could be caused by TV emissions outside the authorized channel, land mobile receiver desensitization or intermodulation. It must install filters and take other precautions as necessary, and submit evidence that no interference is being caused before it will be permitted to transmit programming on the new facilities pursuant to the provisions of §73.1615 or §73.1620 of this part. A TV permittee must reduce its emissions within the land mobile channel of a protected land mobile facility that is receiving interference caused by the TV emission producing a vertically polarized signal and a field strength in excess of 17 dBu at the land mobile receiver site on the land mobile frequency. The TV emission should be measured with equipment set to a 30 kHz measurement bandwidth including the entire applicable land mobile channel. A TV permittee must correct a desensitization problem if its occurrence can be directly linked to the start of the TV operation and the land mobile station is using facilities with typical desensitization rejection characteristics. A TV permittee must identify the source of an intermodulation product that is generated when the TV operation commences. If the intermodulation source is under its control, the TV permittee must correct the problem. If the intermodulation source is beyond the TV permittee's control, it must cooperate in the resolution of the problem and should provide whatever technical assistance it can.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[28 FR 13660, Dec. 14, 1963]

Editorial Note:  For Federal Register citations affecting §73.687, see the List of CFR Sections Affected which appears in the Finding Aids section of the printed volume and on GPO Access.

§ 73.688   Indicating instruments.

(a) Each TV broadcast station shall be equipped with indicating instruments which conform with the specifications described in §73.1215 for measuring the operating parameters of the last radio stage of the visual transmitter, and with such other instruments as are necessary for the proper adjustment, operation, and maintenance of the visual transmitting system.

(b) The function of each instrument shall be clearly and permanently shown on the instrument itself or on the panel immediately adjacent thereto.

(c) In the event that any one of these indicating instruments becomes defective, when no substitute which conforms with the required specifications is available, the station may be operated without the defective instrument pending its repair or replacement for a period not in excess of 60 days without further authority of the FCC, provided that:

(1) If the defective instrument is the transmission line meter used for determining the output power by the direct method, the operating power shall be determined or maintained by the indirect method whenever possible or by using the operating parameters of the last radio stage of the transmitter during the time the station is operated without the transmission line meter.

(2) If conditions beyond the control of the licensee prevent the restoration of the meter to service within the above allowed period, informal request in accordance with §73.3549 may be filed with the Engineer in Charge of the radio district in which the station is located for such additional time as may be required to complete repairs of the defective instrument.

[41 FR 36818, Sept. 1, 1976, as amended at 48 FR 38480, Aug. 24, 1983; 49 FR 50048, Dec. 26, 1984; 50 FR 26568, June 27, 1985]

(a) Each TV station must have measuring equipment for determining that the transmitted visual signal conforms to the provisions of this subpart. The licensee shall decide the monitoring and measurement methods or procedures for indicating and controlling the visual signal.

(b) In the event technical problems make it impossible to operate in accordance with the timing and carrier level tolerance requirements of §73.682 (a)(9)(i), (a)(9)(ii), (a)(12), (a)(13), and (a)(17), a TV broadcast station may operate at variance for a period of not more than 30 days without specific authority from the FCC: provided that, the date and time of the initial out-of-tolerance condition has been entered in the station log. If the operation at variance will exceed 10 consecutive days, a notification must be sent to the FCC in Washington, D.C., not later than the 10th day of such operation. In the event normal operation is resumed prior to the end of the 30 day period, the licensee must notify the FCC upon restoration of normal operation. If causes beyond the control of the licensee prevent restoration of normal operation within 30 days, a written request must be made to the FCC in Washington, D.C., no later than the 30th day for such additional time as may be necessary.

[60 FR 55480, Nov. 1, 1995]

Table I [Reserved]

[28 FR 13660, Dec. 14, 1963, as amended at 39 FR 20377, June 10, 1974; 47 FR 35990, Aug. 18, 1982; 50 FR 23701, June 5, 1985; 54 FR 9807, Mar. 8, 1989]

This section consists of the following Figures 1–5, 5a, 6–10, 10a–10e, 11–12, 13–16.

Note: The charts as reproduced herein, due to their small scale, are not to be used in connection with material submitted to the F.C.C.

Figures 13 through 15 [Reserved]

[28 FR 13660, Dec. 14, 1963, as amended at 36 FR 17429, Aug. 31, 1971; 39 FR 40957, Nov. 22, 1974; 40 FR 27684, July 1, 1975; 41 FR 56326, Dec. 28, 1976; 44 FR 36040, June 20, 1979; 47 FR 3790, Jan. 27, 1982; 47 FR 35990, Aug. 18, 1982; 50 FR 13972, Apr. 9, 1985; 50 FR 23701, June 5, 1985; 50 FR 32205, Aug. 9, 1985; 52 FR 11656, Apr. 10, 1987; 54 FR 9807, Mar. 8, 1989; 58 FR 29983, May 25, 1993]

Effective Date Note:  At 42 FR 25736, May 19, 1977, the effective date of §73.699 Figure 10e was stayed indefinitely.

Subpart F—International Broadcast Stations

The following definitions apply to terminology employed in this subpart:

(a) International broadcast stations. A broadcasting station employing frequencies allocated to the broadcasting service between 5900 and 26100 kHz, the transmissions of which are intended to be received directly by the general public in foreign countries. (A station may be authorized more than one transmitter.) There are both Federal and non-Federal Government international broadcast stations; only the latter are licensed by the Commission and are subject to the rules of this subpart.

(b) Transmitter-hour. One frequency used on one transmitter for one hour.

(c) Frequency-hour. One frequency used for one hour regardless of the number of transmitters over which it is simultaneously broadcast by a station during that hour.

(d) Multiple operation. Broadcasting by a station on one frequency over two or more transmitters simultaneously. If a station uses the same frequency simultaneously on each of two (three, etc.) transmitters for an hour, it uses one frequency-hour and two (three, etc.) transmitter-hours.

(e) Coordinated Universal Time (UTC). Time scale, based on the second (SI), as defined in Recommendation ITU–R TF.460–6. For most practical purposes associated with the ITU Radio Regulations, UTC is equivalent to mean solar time at the prime meridian (0° longitude), formerly expressed in GMT. (RR)

(f) Sunspot number. The 12–month running average of the number of sunspots for any month as indicated in the U.S. Department of Commerce Telecommunications Research and Engineering Report No. 13—available from the Superintendent of Documents, Washington, DC 20402. The sunspot number varies in an approximate 11–year cycle.

(g) Day. Any twenty-four hour period beginning 0100 UTC and ending 0100 UTC.

(h) Schedule A. That portion of any year commencing at 0100 UTC on the last Sunday in March and ending at 0100 UTC on the last Sunday in October.

(i) Schedule B. That portion of any year commencing at 0100 UTC on the last Sunday in October and ending at 0100 UTC on the last Sunday in March.

(j) [Reserved]

(k) Seasonal schedule. An assignment, for a season, of a frequency or frequencies, and other technical parameters, to be used by a station for transmission to particular zones or areas of reception during specified hours.

(l) Reference month. That month of a season which is used for determining predicted propagation characteristics for the season. The reference month for Schedule A is July and the reference month for Schedule B is December.

(m) Maximum usable frequency (MUF). The highest frequency which is returned by ionospheric radio propagation to the surface of the earth for a particular path and time of day for 50 percent of the days of the reference month.

(n) Optimum working frequency (FOT). The highest frequency which is returned by ionospheric radio propagation to the surface of the earth for a particular path and time of day for 90 percent of the days of the reference month.

Note: The international abbreviation for optimum working frequency, FOT, is formed with the initial letters of the French words for “optimum working frequency” which are “frequence optimum de travail.”

(o) Zone of reception. Any geographic zone indicated in §73.703 in which the reception of particular programs is specifically intended and in which broadcast coverage is contemplated.

(p) Area of reception. Any geographic area smaller than a zone of reception in which the reception of particular programs is specifically intended and in which broadcast coverage is contemplated, such areas being indicated by countries or parts of countries.

(q) Delivered median field strength, or field strength. The field strength incident upon the zone or area of reception expressed in microvolts per meter, or decibels above one microvolt per meter, which is exceeded by the hourly median value for 50 percent of the days of the reference month.

(r) Carrier power. The average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle under conditions of no modulation.

[38 FR 18892, July 16, 1973, as amended at 68 FR 25538, May 13, 2003; 70 FR 46676, Aug. 10, 2005]

(a) Frequencies will be assigned by the Commission prior to the start of each season to authorized international broadcasting stations for use during the season at specified hours and for transmission to specified zones or areas of reception, with specified power and antenna bearing. Six months prior to the start of each season, licensees and permittees shall by informal written request, submitted to the Commission in triplicate, indicate for the season the frequency or frequencies desired for transmission to each zone or area of reception specified in the license or permit, the specific hours during which it desires to transmit to such zones or areas on each frequency, and the power, antenna gain, and antenna bearing it desires to use. Requests will be honored to the extent that interference and propagation conditions permit and that they are otherwise in accordance with the provisions of this section.

(b) After necessary processing of the requests required by paragraph (a) of this section, the Commission will notify each licensee and permittee of the frequencies, hours of use thereof to specified zones or areas of reception, power, and antenna bearing which it intends to authorize for the season in question. After receipt of such notification, the licensee or permittee shall, in writing, not later than two months before the start of the season in question, inform the Commission either that it plans to operate in accordance with the authorization which the Commission intends to issue, or that it plans to operate in another manner. If the licensee or permittee indicates that it plans to operate in another manner, it shall furnish explanatory details.

(c) If after submitting the request required under the provisions of paragraph (a) of this section, but before receipt of the Commission's notification referred to in paragraph (b) of this section, the licensee or permittee submits a request for changes of its original request, such requests will be accepted for consideration only if accompanied by statements showing good cause therefor and will be honored only if conditions permit. If the information required to be submitted by the licensee or permittee under the provisions of paragraph (b) of this section indicates that operation in another manner is contemplated, and the explanatory details contain a request for change in the originally proposed manner of operation, such requests will be accepted for consideration only if accompanied by statements showing good cause therefor and will be honored only if conditions permit. If after the licensee or permittee submits the information required under the provisions of paragraph (b) of this section, but before the start of the season in question, the licensee or permittee submits a request for changes in its manner of operation for the season in question, the request will be accepted for consideration only if accompanied by statements showing good cause therefor and will be honored only if conditions permit. If after the start of a season the licensee or permittee submits a request for changes in the manner of operation as authorized, the request will be considered only if accompanied by statements showing good cause therefor, and will be honored only if conditions permit.

(d) The provisions of paragraphs (a), (b), and (c) of the section shall apply to licensees, to permittees operating under program test authority, and to permittees who anticipate applying for and receiving program test authority for operation during the specified season.

Note: Permittees who during the process of construction wish to engage in equipment tests shall by informal written request, submitted to the Commission in triplicate not less than 30 days before they desire to begin such testing, indicate the frequencies they desire to use for testing and the hours they desire to use those frequencies. No equipment testing shall occur until the Commission has authorized frequencies and hours for such testing. Such authorizations shall be only for one season, and if it is desired to continue equipment testing in a following season, new requests for frequencies and hours must be submitted at least 30 days before it is desired to begin testing in the following season.

(e) Within 14 days after the end of each season, a report shall be filed with the Commission by each licensee or permittee operating under program test authority who has been issued a seasonal schedule for that season. The report shall state whether the licensee or permittee has operated the number of frequency-hours authorized by the seasonal schedule to each of the zones or areas of reception specified in the schedule. If such operation has not occurred, a detailed explanation of that fact shall also be submitted which includes specific dates, frequency-hours not used, and reasons for the failure to operate as authorized. The report shall also contain information that has been received by the licensee or permittee as to reception or interference, and conclusions with regard to propagation characteristics of frequencies that were assigned for the season in question.

(f) Exclusive allocations. Where practical, assigned frequencies shall be within the following bands, which are allocated to the broadcasting service on a primary and exclusive basis:

(1) Worldwide allocations. The following bands are allocated to the broadcasting service on a primary and exclusive basis throughout the world: 5950–6200 kHz, 9500–9900 kHz, 11650–12050 kHz, 13600–13800 kHz, 15100–15600 kHz, 17550–17900 kHz, 21450–21850 kHz, and 25670–26100 kHz.

(2) Regional allocation. The band 7200–7300 kHz is allocated to the broadcasting service on a primary and exclusive basis in Region 1 and Region 3.

Note to (f)(2): For the allocation of frequencies, the ITU has divided the world into three Regions, which are defined in 47 CFR 2.104(b). The bands 7100–7300 kHz and 7400–7450 kHz are not allocated to the broadcasting service in Region 2.

(g) Co-primary allocations. Frequencies may also be assigned from within the following bands, which are allocated on a primary, but not exclusive, basis to the broadcasting service:

(1) Worldwide allocations. (i) Until April 1, 2007, the following frequency bands are allocated to the broadcasting and fixed services on a co-primary basis throughout the world: 5900–5950 kHz, 7300–7350 kHz, 9400–9500 kHz, 11600–11650 kHz, 12050–12100 kHz, 13570–13600 kHz, 13800–13870 kHz, 15600–15800 kHz, 17480–17550 kHz, and 18900–19020 kHz (WARC–92 HFBC bands). In addition, the band 5900–5950 kHz is allocated to the land mobile service on a primary basis in Region 1 and to the mobile except aeronautical mobile (R) service on a primary basis in Region 2 until April 1, 2007. After April 1, 2007, the WARC–92 HFBC bands are allocated to the broadcasting service on an exclusive basis throughout the world.

(ii) Until March 29, 2009, the band 7350–7400 kHz is allocated to the broadcasting and fixed services on a co-primary basis throughout the world. After March 29, 2009, the band 7350–7400 kHz is allocated to the broadcasting service on an exclusive basis throughout the world, except in the countries listed in 47 CFR 2.106, footnote 5.143C where the band 7350–7400 kHz continues to be allocated to the broadcasting and fixed services on a co-primary basis.

(2) Regional allocations. (i) Until March 29, 2009, the band 7100–7200 kHz is allocated to the amateur and broadcasting services on a co-primary basis in Region 1 and Region 3; however, during this transition period, the use of the band 7100–7200 kHz by the amateur service shall not impose constraints on the broadcasting service intended for use within Region 1 and Region 3. After March 27, 2005, where practical, requests for frequency assignments in the band 7100–7200 kHz shall be satisfied within the band 7200–7350 kHz. After March 29, 2009, the band 7100–7200 kHz is no longer allocated to the broadcasting service.

(ii) Until March 29, 2009, the band 7400–7450 kHz is allocated to the broadcasting service on a co-primary basis with the fixed service in Region 1 and Region 3. After March 29, 2009, the band 7400–7450 kHz is allocated on an exclusive basis to the broadcasting service in Region 1 and Region 3, except in the countries listed in 47 CFR 2.106, footnote 5.143C where the band 7400–7450 kHz continues to be allocated to the broadcasting and fixed services on a co-primary basis.

(h) Requirements for Regional operation. (1) Frequency assignments in the bands 7100–7300 kHz (7200–7300 kHz after March 29, 2009) and 7400–7450 kHz shall be limited to international broadcast stations that are located in the Pacific insular areas located in Region 3 (as defined in 47 CFR 2.105(a), note 4) that transmit to geographical zones and areas of reception in Region 1 or Region 3.

(2) During the hours of 0800–1600 UTC (Coordinated Universal Time) antenna gain with reference to an isotropic radiator in any easterly direction that would intersect any area in Region 2 shall not exceed 2.15 dBi, except in the case where a transmitter power of less than 100 kW is used. In this case, antenna gain on restricted azimuths shall not exceed that which is determined in accordance with equation below. Stations desiring to operate in this band must submit sufficient antenna performance information to ensure compliance with these restrictions. Permitted gain for transmitter powers less than 100 kW:

Where:

Gi = maximum gain permitted with reference to an isotropic radiator.

Pa = Transmitter power employed in kW.

(i) Frequencies requested for assignment must be as near as practicable to the optimum working frequency (unless otherwise justified) for the zone or area of reception for the period and path of transmission, and should be chosen so that a given frequency will provide the largest period of reliable transmission to the selected zone or area of reception. Moreover, at the zone or area of reception frequencies shall provide protection to the transmissions of other broadcasting stations which, in the opinion of the Commission, have priority of assignment.

Note 1: Requests for frequency-hours shall be accompanied by all pertinent technical data with reference to the frequencies and hours of operation, including calculated field strengths delivered to the zones or areas of reception.

Note 2: It is preferable that calculated field strengths delivered to zones or areas of reception be equal to or greater than those required by I.F.R.B. Technical Standards, Series A (and supplements thereto), in order for the I.F.R.B. to afford the notified assignment protection from interference. Nevertheless, calculated field strengths less than those required by the I.F.R.B. standards for protection will be acceptable to the Commission. However, licensees should note that if such lesser field strengths are submitted no protection from interference will be provided by the I.F.R.B. if their technical examination of such notifications show incompatibilities with other notified assignments fully complying with I.F.R.B. technical standards.

Note 3: Licensees are permitted to engage in multiple operation as defined in §73.701(d).

Note 4: Seasonal requests for frequency-hours will be only for transmissions to zones or areas of reception specified in the basic instrument of authorization. Changes in such zones or areas will be made only on separate application for modification of such instruments.

(j) Not more than one frequency will be assigned for use at any one time for any one program transmission except in instances where a program is intended for reception in more than one zone or area of reception and the intended zones or areas cannot be served by a single frequency: Provided, however, That on a showing of good cause a licensee may be authorized to operate on more than one frequency at any one time to transmit any one program to a single zone or area of reception.

(k) Any frequency assigned to a licensee or permittee shall also be available for assignment to other licensees or permittees.

(l) All assignments of frequencies and the hours during which they will be used will be made with the express understanding that they are subject to immediate cancellation or change without hearing whenever the Commission determines that interference or propagation conditions so require and that each frequency-hour assignment for a given seasonal schedule is unique unto itself and not necessarily available for use during a subsequent season.

(m) The total maximum number of frequency-hours which will be authorized to all licensees of international broadcasting stations during any one day for any season is 100. The number of frequency-hours allocated to any licensee will depend on past usage, availability, and need. If for a forthcoming season the total of the requests for daily frequency-hours of all licensees exceeds 100, all licensees will be notified and each licensee that makes an adequate showing that good cause exists for not having its requested number of frequency-hours reduced and that operation of its station without such reduction would be consistent with the public interest may be authorized the frequency-hours requested.

Note: The provisions of this paragraph are not to be construed to mean that a total of 100 (or more) frequency-hours per day is assured licensees. Frequency-hours will only be assigned to the extent that they are available. It is the responsibility of each licensee to make all technical studies to show that frequency-hours requested by it are available and suitable for use as proposed.

[38 FR 18892, July 16, 1973, as amended at 51 FR 9965, Mar. 24, 1986; 68 FR 25538, May 13, 2003; 70 FR 46676, Aug. 10, 2005]

The zones or areas of reception to be served by international broadcasting stations shall be based on the following map, and directive antennas shall be employed to direct transmissions thereto:

[38 FR 18893, July 16, 1973, as amended at 68 FR 25538, May 13, 2003]

(a) During the process of construction of an international broadcasting station, the permittee, having obtained authorization for frequencies and hours as set forth in the Note to §73.702(d) may, without further authority of the FCC, conduct equipment tests for the purpose of such adjustments and measurements as may be necessary to assure compliance with the terms of the construction permit, the technical provisions of the application therefor and the rules and regulations. Such tests shall use voice identification and test tones only. No programming shall be conducted during equipment tests.

(b) The Commission may notify the permittee to conduct no tests or may cancel, suspend, or change the date for the beginning of equipment tests when and if such action may appear to be in the public interest, convenience, and necessity.

(c) Equipment tests may be continued so long as the construction permit shall remain valid: Provided, however, That the procedure set forth in paragraph (a) of this section must be repeated prior to the conducting of such tests in each season after the season in which the testing began.

(d) The authorization for tests embodied in this section shall not be construed as constituting a license to operate but as a necessary part of construction.

[28 FR 13696, Dec. 14, 1963, as amended at 37 FR 25842, Dec. 5, 1972. Redesignated and amended at 38 FR 18894, July 16, 1973; 47 FR 40174, Sept. 13, 1982]

(a) Upon completion of construction of an international broadcasting station in accordance with the terms of the construction permit, the technical provisions of the application therefor, and the rules and regulations and the applicable engineering standards, and when an application for station license has been filed showing the station to be in satisfactory operating condition, the permittee may request authority to conduct program tests. Such request shall be filed with the FCC at least 10 days prior to the date on which it is desired to begin such operation. All data necessary to show compliance with the terms and conditions of the construction permit must be filed with the license application.

(b) Program tests shall not commence until specific Commission authority is received. The Commission reserves the right to change the date of the beginning of such tests or to suspend or revoke the authority for program tests as and when such action may appear to be in the public interest, convenience, and necessity.

(c) Unless sooner suspended or revoked, program test authority continues valid during Commission consideration of the application for license and during this period further extension of the construction permit is not required. Program test authority shall be automatically terminated by final determination upon the application for station license.

(d) All operation under program test authority shall be in strict compliance with the rules governing international broadcasting stations and in strict accordance with representations made in the application for license pursuant to which the tests were authorized.

(e) The granting of program test authority shall not be construed as approval by the Commission of the application for station license.

[38 FR 18894, July 16, 1973, as amended at 47 FR 40174, Sept. 13, 1982]

(a) A license for an international broadcasting station will be issued only after a satisfactory showing has been made in regard to the following, among others:

(1) That there is a need for the international broadcasting service proposed to be rendered.

(2) That the necessary program sources are available to the applicant to render the international service proposed.

(3) That the production of the program service and the technical operation of the proposed station will be conducted by qualified persons.

(4) That the applicant is legally, technically and financially qualified and possesses adequate technical facilities to carry forward the service proposed.

(5) That the public interest, convenience and necessity will be served through the operation of the proposed station.

[38 FR 18895, July 16, 1973]

Authorizations issued to international broadcasting stations by the Commission will be authorizations to permit the construction or use of a particular transmitting equipment combination and related antenna systems for international broadcasting, and to permit broadcasting to zones or areas of reception specified on the instrument of authorization. The authorizations will not specify the frequencies to be used or the hours of use. Requests for frequencies and hours of use will be made as provided in §73.702. Seasonal schedules, when issued pursuant to the provisions of §73.702, will become attachments to and part of the instrument of authorization, replacing any such prior attachments.

[38 FR 18895, July 16, 1973]

All international broadcast station licenses will be issued so as to expire at the hour of 3 a.m. local time and will be issued for a normal period of 8 years expiring November 1.

[62 FR 5347, Feb. 5, 1997]

No international broadcast station shall be authorized to install, or be licensed for operation of, transmitter equipment with:

(a) A rated carrier power of less than 50 kilowatts (kW) if double-sideband (DSB) modulation is used,

(b) A peak envelope power of less than 50 kW if single-sideband (SSB) modulation is used, or

(c) A mean power of less than 10 kW if digital modulation is used.

[70 FR 46676, Aug. 10, 2005]

All international broadcasting stations shall operate with directional antennas. Such antennas shall be designed and operated so that the radiated power in the maximum lobe toward the specific zone or area of reception intended to be served shall be at least 10 times the average power from the antenna in the horizontal plane. Radiation in all other directions shall be suppressed to the maximum extent technically feasible. In order to eliminate or mitigate harmful interference, the direction of the maximum lobe may be adjusted upon approval of the Commission.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[38 FR 18895, July 16, 1973, as amended at 44 FR 65765, Nov. 15, 1979]

(a) The licensee of each international broadcast station shall operate a frequency monitor at the transmitter independent of the frequency control of the transmitter.

(b) The frequency monitor shall be designed and constructed in accordance with good engineering practice. It shall have an accuracy sufficient to determine that the operating frequency is within one-half of the allowed tolerance.

[37 FR 25842, Dec. 5, 1972]

The licensee of each international broadcast station shall have a modulation monitor in operation at the transmitter.

[37 FR 25842, Dec. 5, 1972]

(a) Channel spacing. The nominal spacing for DSB shall be 10 kHz. However, the interleaved channels with a separation of 5 kHz may be used in accordance with the relative protection criteria, provided that the interleaved emission is not to the same geographical area as either of the emissions between which it is interleaved.

(b) Emission characteristics—(1) Nominal carrier frequencies. Nominal carrier frequencies shall be integral multiples of 5 kHz.

(2) Audio-frequency band. The upper limit of the audio-frequency band (at—3 dB) of the transmitter shall not exceed 4.5 kHz and the lower limit shall be 150 Hz, with lower frequencies attenuated at a slope of 6 dB per octave.

(3) Modulation processing. If audio-frequency signal processing is used, the dynamic range of the modulating signal shall be not less than 20 dB.

(4) Necessary bandwidth. The necessary bandwidth shall not exceed 9 kHz.

[70 FR 46677, Aug. 10, 2005]

(a) System parameters—(1) Channel spacing. In a mixed DSB, SSB and digital environment (see Resolution 517 (Rev.WRC–03)), the channel spacing shall be 10 kHz. In the interest of spectrum conservation, it is also permissible to interleave SSB emissions midway between two adjacent DSB channels, i.e., with 5 kHz separation between carrier frequencies, provided that the interleaved emission is not to the same geographical area as either of the emissions between which it is interleaved. In an all inclusive SSB environment, the channel spacing and carrier frequency separation shall be 5 kHz.

(2) Equivalent sideband power. When the carrier reduction relative to peak envelope power is 6 dB, an equivalent SSB emission is one giving the same audio-frequency signal-to-noise ratio at the receiver output as the corresponding DSB emission, when it is received by a DSB receiver with envelope detection. This is achieved when the sideband power of the SSB emission is 3 dB larger than the total sideband power of the DSB emission. (The peak envelope power of the equivalent SSB emission and the carrier power are the same as that of the DSB emission.)

(b) Emission characteristics—(1) Nominal carrier frequencies. Nominal carrier frequencies shall be integral multiples of 5 kHz.

(2) Frequency tolerance. The frequency tolerance shall be 10 Hz.

Note 1 to Paragraph (b)(2): The ITU suggests that administrations avoid carrier frequency differences of a few hertz, which cause degradations similar to periodic fading. This could be avoided if the frequency tolerance were 0.1 Hz, a tolerance which would be suitable for SSB emissions.

Note 2 to Paragraph (b)(2): The SSB system adopted for the bands allocated exclusively to HF broadcasting does not require a frequency tolerance less than 10 Hz. The degradation mentioned in Note 1 occurs when the ratio of wanted-to-interfering signal is well below the required protection ratio. This remark is equally valid for both DSB and SSB emissions.

(3) Audio-frequency band. The upper limit of the audio-frequency band (at—3 dB) of the transmitter shall not exceed 4.5 kHz with a further slope of attenuation of 35 dB/kHz and the lower limit shall be 150 Hz with lower frequencies attenuated at a slope of 6 dB per octave.

(4) Modulation processing. If audio-frequency signal processing is used, the dynamic range of the modulating signal shall be not less than 20 dB.

(5) Necessary bandwidth. The necessary bandwidth shall not exceed 4.5 kHz.

(6) Carrier reduction (relative to peak envelope power). In a mixed DSB, SSB and digital environment, the carrier reduction shall be 6 dB to allow SSB emissions to be received by conventional DSB receivers with envelope detection without significant deterioration of the reception quality.

(7) Sideband to be emitted. Only the upper sideband shall be used.

(8) Attenuation of the unwanted sideband. The attenuation of the unwanted sideband (lower sideband) and of intermodulation products in that part of the emission spectrum shall be at least 35 dB relative to the wanted sideband signal level. However, since there is in practice a large difference between signal amplitudes in adjacent channels, a greater attenuation is recommended.

[70 FR 46677, Aug. 10, 2005]

(a) For digitally modulated emissions, the Digital Radio Mondiale (DRM) standard shall be employed. Both digital audio broadcasting and datacasting are authorized. The RF requirements for the DRM system are specified in paragraphs (b) and (c), of this section.

(b) System parameters—(1) Channel spacing. The initial spacing for digitally modulated emissions shall be 10 kHz. However, interleaved channels with a separation of 5 kHz may be used in accordance with the appropriate protection criteria appearing in Resolution 543 (WRC–03), provided that the interleaved emission is not to the same geographical area as either of the emissions between which it is interleaved.

(2) Channel utilization. Channels using digitally modulated emissions may share the same spectrum or be interleaved with analog emissions in the same high frequency broadcasting (HFBC) band, provided the protection afforded to the analog emissions is at least as great as that which is currently in force for analog-to-analog protection. Accomplishing this may require that the digital spectral power density (and total power) be lower by several dB than is currently used for either DSB or SSB emissions.

(c) Emission characteristics—(1) Bandwidth and center frequency. A full digitally modulated emission will have a 10 kHz bandwidth with its center frequency at any of the 5 kHz center frequency locations in the channel raster currently in use within the HFBC bands. Among several possible “simulcast” modes are those having a combination of analog and digital emissions of the same program in the same channel, that may use a digital emission of 5 kHz or 10 kHz bandwidth, next to either a 5 kHz or 10 kHz analog emission. In all cases of this type, the 5 kHz interleaved raster used in HFBC shall be adhered to in placing the emission within these bands.

(2) Frequency tolerance. The frequency tolerance shall be 10 Hz. See Section 73.757(b)(2), notes 1 and 2.

(3) Audio-frequency band. The quality of service, using digital source coding within a 10 kHz bandwidth, taking into account the need to adapt the emission coding for various levels of error avoidance, detection and correction, can range from the equivalent of monophonic FM (approximately 15 kHz) to the low-level performance of a speech codec (of the order of 3 kHz). The choice of audio quality is connected to the needs of the broadcaster and listener, and includes the consideration of such characteristics as the propagation conditions expected. There is no single specification, only the upper and lower bounds noted in this paragraph.

(4) Modulation. Quadrature amplitude modulation (QAM) with orthogonal frequency division multiplexing (OFDM) shall be used. 64–QAM is feasible under many propagation conditions; others such as 32–, 16– and 8–QAM are specified for use when needed.

(5) RF protection ratio values. The protection ratio values for analogue and digital emissions for co-channel and adjacent channel conditions shall be in accordance with Resolution 543 (WRC–03) as provisional RF protection ratio values subject to revision or confirmation by a future competent conference.

[70 FR 46677, Aug. 10, 2005]

Upon showing that a need exists for the use of auxiliary transmitters, a license may be issued provided that:

(a) Auxiliary transmitters may be installed either at the same location as the main transmitters or at another location.

(b) [Reserved]

(c) The auxiliary transmitters shall be maintained so that they may be put into immediate operation at any time for the following purposes:

(1) The transmission of the regular programs upon the failure of the main transmitters.

(2) The transmission of regular programs during maintenance or modification work on the main transmitter, necessitating discontinuance of its operation for a period not to exceed 5 days. (This includes the equipment changes which may be made without authority as set forth elsewhere in the rules and regulations or as authorized by the Commission by letter or by construction permit. Where such operation is required for periods in excess of 5 days, request therefor shall be in accordance with §73.3542 of this chapter.)

(3) Upon request by a duly authorized representative of the Commission.

(d) The auxiliary transmitters shall be tested at least once each week to determine that they are in proper operating condition and that they are adjusted to the proper frequency except that in the case of operation in accordance with paragraph (c) of this section during any week, the test in that week may be omitted provided the operation under paragraph (c) of this section is satisfactory. A record shall be kept of the time and result of each test. Such records shall be retained for a period of two years.

(e) The auxiliary transmitters shall be equipped with satisfactory control equipment which will enable the maintenance of the frequency emitted by the station within the limits prescribed by the regulations in this part.

(f) The operating power of an auxiliary transmitter may be less but not greater than the authorized power of the main transmitters.

[28 FR 13696, Dec. 14, 1963, as amended at 37 FR 25843, Dec. 5, 1972; 60 FR 55480, Nov. 1, 1995. Redesignated at 70 FR 46677, Aug. 10, 2005]

The licensee of an international broadcast station may be licensed for alternate main transmitters provided that a technical need for such alternate transmitters is shown and that the following conditions are met: Both transmitters:

(a) Are located at the same place;

(b) Shall have the same power rating; and

(c) Shall meet the construction, installation, operation, and performance requirements of good engineering practice.

[37 FR 25843, Dec. 5, 1972. Redesignated at 70 FR 46677, Aug. 10, 2005]

Specific authority, upon filing formal application (FCC Form 309) therefor, is required for any of the following changes:

(a) Change involving an increase or decrease in the power rating of the transmitters.

(b) A replacement of the transmitters as a whole.

(c) Change in the location of the transmitting antenna.

(d) Change in location of main studio, if it is proposed to move the main studio to a different city from that specified in the license.

(e) Change in the power delivered to the antenna.

(f) Change in frequency control and/or modulation system.

(g) Change in direction or gain of antenna system.

Other changes, not specified above in this section, may be made at any time without the authority of the Commission: Provided, That the Commission shall be immediately notified thereof and such changes shall be shown in the next application for renewal of license.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[38 FR 18895, July 16, 1973, as amended at 44 FR 65765, Nov. 15, 1979. Redesignated at 70 FR 46677, Aug. 10, 2005]

(a) All international broadcasting stations shall operate in accordance with the times indicated on their seasonal schedules.

(b) In the event that causes beyond a licensee's control make it impossible to adhere to the seasonal schedule or to continue operating, the station may limit or discontinue operation for a period of not more than 10 days, without further authority from the FCC. However, in such cases, the FCC shall be immediately notified in writing of such limitation or discontinuance of operation and shall subsequently be notified when the station resumes regular operation.

(c) In the event that causes beyond a licensee's control make it impossible to adhere to the seasonal schedule or to continue operating for a temporary period of more than 10 days, the station may not limit or discontinue operation until it requests and receives specific authority to do so from the FCC. When the station subsequently resumes regular operation after such limited operation or discontinuance of operation, it shall notify the FCC in Washington, DC. The license of a broadcasting station that fails to transmit broadcast signals for any consecutive 12-month period expires as a matter of law at the end of that period, notwithstanding any provision, term, or condition of the license to the contrary.

[38 FR 18895, July 16, 1973, as amended at 47 FR 40174, Sept. 13, 1982; 61 FR 28767, June 6, 1996. Redesignated at 70 FR 46677, Aug. 10, 2005]

The operating power specified in §73.751 shall be determined by use of a calibrated dummy load or by any other method specified by the licensee and accepted by the Commission. Such method may subsequently be used by the licensee to maintain the authorized operating power.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[38 FR 18895, July 16, 1973, as amended at 44 FR 65765, Nov. 15, 1979]

The licensee or permittee of each international broadcast station must maintain the station log in the following manner:

(a) In the program log:

(1) An entry of the time each station identification announcement (call letters and location) is made.

(2) An entry briefly describing each program broadcast, such as “music”, “drama”, “speech”, etc., together with the name or title thereof, language, and the sponsor's name, with the time of the beginning and ending of the complete program.

(3) For each program of network origin, an entry showing the name of the network originating the program.

[28 FR 13696, Dec. 14, 1963, as amended at 37 FR 25843, Dec. 5, 1972; 48 FR 38480, Aug. 24, 1983]

Logs of international broadcast stations shall be retained by the licensee or permittee for a period of two years: Provided, however, That logs involving communications incident to a disaster or which include communications incident to or involved in an investigation by the Commission and concerning which the licensee or permittee has been notified, shall be retained by the licensee or permittee until he is specifically authorized in writing by the Commission to destroy them: Provided, further, That logs incident to or involved in any claim or complaint of which the licensee or permittee has notice shall be retained by the licensee or permittee until such claim or complaint has been fully satisfied or until the same has been barred by statute limiting the time for the filing of suits upon such claims.

[28 FR 13696, Dec. 14, 1963]

(a) A licensee of an international broadcast station shall make station identification announcement (call letters and location), at the beginning and ending of each time of operation and during the operation on the hour.

(b) Station identification, program announcements, and oral continuity shall be made with international significance (language particularly) which is designed for the foreign country or countries for which the service is primarily intended.

[28 FR 13696, Dec. 14, 1963, as amended at 34 FR 19762, Dec. 17, 1969; 38 FR 18896, July 16, 1973]

(a) A licensee of an international broadcast station shall render only an international broadcast service which will reflect the culture of this country and which will promote international goodwill, understanding, and cooperation. Any program solely intended for and directed to an audience in the continental United States does not meet the requirements for this service.

(b) Such international broadcast service may include commercial or sponsored programs: Provided, That:

(1) Commercial program continuities give no more than the name of the sponsor of the program and the name and general character of the commodity, utility or service, or attraction advertised.

(2) In case of advertising a commodity, the commodity is regularly sold or is being promoted for sale on the open market in the foreign country or countries to which the program is directed in accordance with paragraph (c) of this section.

(3) In case of advertising an American utility or service to prospective tourists or visitors to the United States, the advertisement continuity is particularly directed to such persons in the foreign country or countries where they reside and to which the program is directed in accordance with paragraph (c) of this section.

(4) In case of advertising an international attraction (such as a world fair, resort, spa, etc.) to prospective tourists or visitors to the United States, the oral continuity concerning such attraction is consistent with the purpose and intent of this section.

(5) In case of any other type of advertising, such advertising is directed to the foreign country or countries to which the program is directed and is consistent with the purpose and intent of this section.

(c) The geographic areas to be served by international broadcasting stations are the zones and areas of reception shown in §73.703.

(d) An international broadcast station may transmit the program of a AM broadcast station or network system: Provided, That the conditions in paragraph (b) of this section as to any commercial continuities are observed and when station identifications are made, only the call letter designation of the international station is given and its assigned frequency: And provided further, That in the case of chain broadcasting the program is not carried simultaneously by another international station (except another station owned by the same licensee operated on a frequency in a different group to obtain continuity of signal service), the signals from which are directed to the same area. (See section 3(p) of the Communications Act of 1934 for the definition of “chain broadcasting.”)

[28 FR 13696, Dec. 14, 1963, as amended at 37 FR 25843, Dec. 5, 1972; 38 FR 18896, July 16, 1973]

Source:  65 FR 7640, Feb. 15, 2000, unless otherwise noted.

§ 73.801   Broadcast regulations applicable to LPFM stations.

The following rules are applicable to LPFM stations:

Section 73.201  Numerical definition of FM broadcast channels.

Except as provided in §73.220 of this chapter, all of the frequencies listed in §73.201 of this chapter are available for LPFM stations.

Minimum separation requirements for LP100 and LP10 stations, as defined in §§73.811 and 73.853, are listed in the following paragraphs. An LPFM station will not be authorized unless these separations are met. Minimum distances for co-channel and first-adjacent channel are separated into two columns. The left-hand column lists the required minimum separation to protect other stations and the right-hand column lists (for informational purposes only) the minimum distance necessary for the LPFM station to receive no interference from other stations assumed to operating at the maximum permitted facilities for the station class. For second- and third-adjacent channels and IF channels, the required minimum distance separation is sufficient to avoid interference received from other stations.

(a)(1) An LP100 station will not be authorized initially unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period for LP100 stations, authorized LP100 stations, LP100 station applications that were timely-filed within a previous window, and vacant FM allotments. LP100 stations are not required to protect LP10 stations. LPFM modification applications must either meet the distance separations in the following table or, if short-spaced, not lessen the spacing to subsequently authorized stations.

(2) LP100 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (a)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency.

(b)(1) An LP10 station will not be authorized unless the minimum distance separations in the following table are met with respect to authorized FM stations, applications for new and existing FM stations filed prior to the release of the public notice announcing an LPFM window period for LP10 stations, vacant FM allotments, or LPFM stations.

(2) LP10 stations must satisfy the second-adjacent channel minimum distance separation requirements of paragraph (b)(1) of this section with respect to any third-adjacent channel FM station that, as of September 20, 2000 (the adoption date of this MO&O) broadcasts a radio reading service via a subcarrier frequency.

(c) In addition to meeting or exceeding the minimum separations for Class LP100 and Class LP10 stations in paragraphs (a) and (b) of this section, new LP100 and LP10 stations will not be authorized in Puerto Rico or the Virgin Islands unless the minimum distance separations in the following tables are met with respect to authorized or proposed FM stations:

(1) LP100 stations in Puerto Rico and the Virgin Islands:

(2) LP10 stations in Puerto Rico and the Virgin Islands:

Note to paragraphs (a), (b), and (c): Minimum distance separations towards “grandfathered” superpowered Reserved Band stations are as specified.

(d) In addition to meeting the separations (a) through (c), LPFM applications must meet the minimum separation requirements with respect to authorized FM translator stations, cutoff FM translator applications, and FM translator applications filed prior to the release of the Public Notice announcing the LPFM window period:

(1) LP100 stations:

(2) LP10 Stations:

(e) Existing Class LP100 and LP10 stations which do not meet the separations in paragraphs (a) through (e) of this section may be relocated provided that the separation to any short-spaced station is not reduced.

(f) Commercial and noncommercial educational stations authorized under subparts B and C of this part, as well as new or modified commercial FM allotments, are not required to adhere to the separations specified in this rule section, even where new or increased interference would be created.

(g) International considerations within the border zones. (1) Within 320 km of the Canadian border, LP100 stations must meet the following minimum separations with respect to any Canadian stations:

(2) Within 320 km of the Mexican border, LP100 stations must meet the following separations with respect to any Mexican stations:

(3) Within 320 km of the Canadian border, LP10 stations must meet the following minimum separations with respect to any Canadian stations:

(4) Within 320 km of the Mexican border, LP10 stations must meet the following separations with respect to any Mexican stations:

(5) The Commission will notify the International Telecommunications Union (ITU) of any LPFM authorizations in the US Virgin Islands. Any authorization issued for a US Virgin Islands LPFM station will include a condition that permits the Commission to modify, suspend or terminate without right to a hearing if found by the Commission to be necessary to conform to any international regulations or agreements.

(6) The Commission will initiate international coordination of a LPFM proposal even where the above Canadian and Mexican spacing tables are met, if it appears that such coordination is necessary to maintain compliance with international agreements.

[65 FR 7640, Feb. 15, 2000, as amended at 65 FR 67299, Nov. 9, 2000; 65 FR 79779, Dec. 20, 2000; 66 FR 23863, May 10, 2001]

For the purposes of determining compliance with any LPFM distance requirements, distances shall be calculated in accordance with §73.208(c) of this part.

(a) It shall be the responsibility of the licensee of an LPFM station to correct at its expense any condition of interference to the direct reception of the signal of any subsequently authorized commercial or NCE FM station that operates on the same channel, first-adjacent channel, second-adjacent channel or intermediate frequency (IF) channels as the LPFM station, where interference is predicted to occur and actually occurs within:

(1) The 3.16 mV/m (70 dBu) contour of such stations;

(2) The community of license of a commercial FM station; or

(3) Any area of the community of license of an NCE FM station that is predicted to receive at least a 1 mV/m (60 dBu) signal. Predicted interference shall be calculated in accordance with the ratios set forth in §§73.215(a)(1) and 73.215(a)(2). Intermediate Frequency (IF) channel interference overlap will be determined based upon overlap of the 91 dBu F(50,50) contours of the FM and LPFM stations. Actual interference will be considered to occur whenever reception of a regularly used signal is impaired by the signals radiated by the LPFM station.

(b) An LPFM station will be provided an opportunity to demonstrate in connection with the processing of the commercial or NCE FM application that interference as described in paragraph (a) of this section is unlikely. If the LPFM station fails to so demonstrate, it will be required to cease operations upon the commencement of program tests by the commercial of NCE FM station.

(c) Complaints of actual interference by an LPFM station subject to paragraphs (a) and (b) of this section must be served on the LPFM licensee and the Federal Communications Commission, attention Audio Services Division. The LPFM station must suspend operations within twenty-four hours of the receipt of such complaint unless the interference has been resolved to the satisfaction of the complainant on the basis of suitable techniques. An LPFM station may only resume operations at the direction of the Federal Communications Commission. If the Commission determines that the complainant has refused to permit the LPFM station to apply remedial techniques that demonstrably will eliminate the interference without impairment of the original reception, the licensee of the LPFM station is absolved of further responsibility for the complaint.

(d) It shall be the responsibility of the licensee of an LPFM station to correct any condition of interference that results from the radiation of radio frequency energy outside its assigned channel. Upon notice by the FCC to the station licensee or operator that such interference is caused by spurious emissions of the station, operation of the station shall be immediately suspended and not resumed until the interference has been eliminated. However, short test transmissions may be made during the period of suspended operation to check the efficacy of remedial measures.

(e) In each instance where suspension of operation is required, the licensee shall submit a full report to the FCC in Washington, DC, after operation is resumed, containing details of the nature of the interference, the source of the interfering signals, and the remedial steps taken to eliminate the interference.

[65 FR 7640, Feb. 15, 2000, as amended at 65 FR 67302, Nov. 9, 2000]

(a) An LPFM station is required to provide copies of all complaints alleging that the signal of such LPFM station is interfering with or impairing the reception of the signal of a full power station to such affected full power station.

(b) A full power station shall review all complaints it receives, either directly or indirectly, from listeners regarding alleged interference caused by the operations of an LPFM station. Such full power station shall also identify those that qualify as bona fide complaints under this section and promptly provide such LPFM station with copies of all bona fide complaints. A bona fide complaint:

(1) Is a complaint alleging third adjacent channel interference caused by an LPFM station that has its transmitter site located within the predicted 60 dBu contour of the affected full power station as such contour existed as of the date the LPFM station construction permit was granted;

(2) Must be in the form of an affidavit, and state the nature and location of the alleged interference;

(3) Must involve a fixed receiver located within the 60 dBu contour of the affected full power station and not more than one kilometer from the LPFM transmitter site; and

(4) Must be received by either the LPFM or full power station within one year of the date on which the LPFM station commenced broadcasts with its currently authorized facilities.

(c) An LPFM station will be given a reasonable opportunity to resolve all interference complaints. A complaint will be considered resolved where the complainant does not reasonably cooperate with an LPFM station's remedial efforts.

(d) In the event that the number of unresolved complaints plus the number of complaints for which the source of interference remains in dispute equals at least one percent of the households within one kilometer of the LPFM transmitter site or thirty households, whichever is less, the LPFM and full power stations must cooperate in an “on-off” test to determine whether the interference is traceable to the LPFM station.

(e) If the number of unresolved and disputed complaints exceeds the numeric threshold specified in subsection (d) following an “on-off” test, the full power station may request that the Commission initiate a proceeding to consider whether the LPFM station license should be modified or cancelled, which will be completed by the Commission within 90 days. Parties may seek extensions of the 90 day deadline consistent with Commission rules.

(f) An LPFM station may stay any procedures initiated pursuant to paragraph (e) of this section by voluntarily ceasing operations and filing an application for facility modification within twenty days of the commencement of such procedures.

[65 FR 67302, Nov. 9, 2000; 65 FR 69458, Nov. 17, 2000]

(a) LP100 stations: (1) Maximum facilities. LP100 stations will be authorized to operate with maximum facilities of 100 watts effective radiated power (ERP) at 30 meters antenna height above average terrain (HAAT). An LP100 station with a HAAT that exceeds 30 meters will not be permitted to operate with an ERP greater than that which would result in a 60 dBu contour of 5.6 kilometers. In no event will an ERP less than one watt be authorized. No facility will be authorized in excess of one watt ERP at 450 meters HAAT.

(2) Minimum facilities. LP100 stations may not operate with facilities less than 50 watts ERP at 30 meters HAAT or the equivalent necessary to produce a 60 dBu contour that extends at least 4.7 kilometers.

(b) LP10 stations: (1) Maximum Facilities. LP10 stations will be authorized to operate with maximum facilities of 10 watts ERP at 30 meters HAAT. An LP10 station with a HAAT that exceeds 30 meters will not be permitted to operate with an ERP greater than that which would result in a 60 dBu contour of 3.2 kilometers. In no event will an ERP less than one watt be authorized. No facility will be authorized in excess of one watt ERP at 100 meters HAAT.

(2) Minimum Facilities. LP10 stations may not operate with less than one watt ERP.

(a) Effective radiated power (ERP) will be rounded to the nearest watt on LPFM authorizations.

(b) Antenna radiation center, antenna height above average terrain (HAAT), and antenna supporting structure height will all be rounded to the nearest meter on LPFM authorizations.

HAAT determinations for LPFM stations will be made in accordance with the procedure detailed in §73.313(d) of this part.

(a) Permittees and licensees may employ nondirectional antennas with horizontal only polarization, vertical only polarization, circular polarization or elliptical polarization.

(b) Directional antennas will not be authorized and may not be utilized in the LPFM service, except as provided in paragraph (c) of this section.

(c) Public safety and transportation permittees and licensees, eligible pursuant to §73.853(a)(ii), may utilize directional antennas in connection with the operation of a Travelers' Information Service (TIS) provided each LPFM TIS station utilizes only a single antenna with standard pattern characteristics that are predetermined by the manufacturer. In no event may composite antennas (i.e., antennas that consist of multiple stacked and/or phased discrete transmitting antennas) and/or transmitters be employed.

(d) LPFM TIS stations will be authorized as nondirectional stations. The use of a directional antenna as provided for in paragraph (c) of this section will not be considered in the determination of compliance with any requirements of this part.

[65 FR 67303, Nov. 9, 2000]

(a) LPFM stations will be authorized on Channels 201 through 220 only if the pertinent minimum separation distances in the following table are met with respect to all full power TV Channel 6 stations.

(b) LPFM stations will be authorized on Channels 201 through 220 only if the pertinent minimum separation distances in the following table are met with respect to all low power TV, TV translator, and Class A TV stations authorized on TV Channel 6.

[65 FR 67303, Nov. 9, 2000]

(a) An authorized LPFM station will not be permitted to continue to operate if an FM translator or FM booster station demonstrates that the LPFM station is causing actual interference to the FM translator or FM booster station's input signal, provided that the same input signal was in use at the time the LPFM station was authorized.

(b) Complaints of actual interference by an LPFM station subject to paragraph (a) of this section must be served on the LPFM licensee and the Federal Communications Commission, attention Audio Services Division. The LPFM station must suspend operations upon the receipt of such complaint unless the interference has been resolved to the satisfaction of the complainant on the basis of suitable techniques. Short test transmissions may be made during the period of suspended operation to check the efficacy of remedial measures. An LPFM station may only resume full operation at the direction of the Federal Communications Commission. If the Commission determines that the complainant has refused to permit the LPFM station to apply remedial techniques that demonstrably will eliminate the interference without impairment of the original reception, the licensee of the LPFM station is absolved of further responsibility for the complaint.

[65 FR 67303, Nov. 9, 2000]

The transmitter power output (TPO) of an LPFM station must be determined by the procedures set forth in §73.267 of this part. The operating TPO of an LPFM station with an authorized TPO of more than ten watts must be maintained as near as practicable to its authorized TPO and may not be less than 90% of the minimum TPO nor greater than 105% of the maximum authorized TPO. An LPFM station with an authorized TPO of ten watts or less may operate with less than the authorized power, but not more than 105% of the authorized power.

Each LPFM licensee is responsible for maintaining and operating its broadcast station in a manner that complies with the technical rules set forth elsewhere in this part and in accordance with the terms of the station authorization. In the event that an LPFM station is operating in a manner that is not in compliance with the technical rules set forth elsewhere in this part or the terms of the station authorization, broadcast operation must be terminated within three hours.

(a) All LPFM stations will be licensed for unlimited time operation, except those stations operating under a time sharing agreement pursuant to §73.872.

(b) All LPFM stations are required to operate at least 36 hours per week, consisting of at least 5 hours of operation per day on at least 6 days of the week; however, stations licensed to educational institutions are not required to operate on Saturday or Sunday or to observe the minimum operating requirements during those days designated on the official school calendar as vacation or recess periods.

(a) An LPFM station may be licensed only to:

(1) Nonprofit educational organizations and upon a showing that the proposed station will be used for the advancement of an educational program; and

(2) State and local governments and non-government entities that will provide non-commercial public safety radio services.

(b) Only local applicants will be permitted to submit applications for a period of two years from the date that LP100 and LP10 stations, respectively, are first made available for application. For the purposes of this paragraph, an applicant will be deemed local if it can certify that:

(1) The applicant, its local chapter or branch is physically headquartered or has a campus within 16.1 km (10 miles) of the proposed site for the transmitting antenna;

(2) It has 75% of its board members residing within 16.1 km (10 miles) of the proposed site for the transmitting antenna; or

(3) In the case of any applicant proposing a public safety radio service, the applicant has jurisdiction within the service area of the proposed LPFM station.

No application for an LPFM station may be granted unless the applicant certifies, under penalty of perjury, that neither the applicant, nor any party to the application, has engaged in any manner including individually or with persons, groups, organizations or other entities, in the unlicensed operation of any station in violation of Section 301 of the Communications Act of 1934, as amended, 47 U.S.C. 301.

[66 FR 23863, May 10, 2001]

(a) No authorization for an LPFM station shall be granted to any party if the grant of that authorization will result in any such party holding an attributable interest in two LPFM stations separated by less than 12 km (7 miles).

(b) Except as provided in paragraph (b)(4) of this section, nationwide ownership limits will be phased in according to the following schedule:

(1) For a period of two years from the date that the LPFM stations are first made available for application, a party may hold an attributable interest in no more than one LPFM station.

(2) For the period between two and three years from the date that the initial filing window opens for LPFM applications, a party may hold an attributable interest in no more than five LPFM stations.

(3) After three years from the date that the initial filing window opens for LPFM stations, a party may hold an attributable interest in no more than ten stations.

(4) Not-for-profit organizations and governmental entities with a public safety purpose may be granted multiple licenses only if:

(i) One of the multiple applications is submitted as a priority application, and;

(ii) The remaining non-priority applications do not face a mutually exclusive challenge.

[65 FR 7640, Feb. 15, 2000, as amended at 65 FR 67303, Nov. 9, 2000]

Ownership and other interests in LPFM station permittees and licensees will be attributed to their holders and deemed cognizable for the purposes of §§73.855 and 73.860, in accordance with the provisions of §73.3555, subject to the following exceptions:

(a) A director of an entity that holds an LPFM license will not have such interest treated as attributable if such director also holds an attributable interest in a broadcast licensee or other media entity but recuses himself or herself from any matters affecting the LPFM station.

(b) A local chapter of a national or other large organization shall not have the attributable interests of the national organization attributed to it provided that the local chapter is separately incorporated and has a distinct local presence and mission.

(c) A parent or subsidiary of a LPFM licensee or permittee that is a non-stock corporation will be treated as having an attributable interest in such corporation. The officers, directors, and members of a non-stock corporation's governing body and of any parent or subsidiary entity will have such positional interests attributed to them.

(a) Except as provided in paragraph (b) of this section, no license for an LPFM station shall be granted to any party if the grant of such authorization will result in the same party holding an attributable interest in any other non-LPFM broadcast station, including any FM translator or low power television station, or any other media subject to our broadcast ownership restrictions.

(b) A party with an attributable interest in a broadcast radio station must divest such interest prior to the commencement of operations of an LPFM station in which the party also holds an interest unless such party is a college or university that can certify that the existing broadcast radio station is not student run. This exception applies only to parties that;

(1) Are accredited educational institutions, and;

(2) Own attributable interest in non-student run broadcast stations;

(3) Apply for an authorization for an LPFM station that will be managed and operated on a day-to-day basis by students of the accredited educational institution; and

(4) Do not face competing applications for the LPFM authorization.

(c) No LPFM licensee may enter into an operating agreement of any type, including a time brokerage or management agreement, with either a full power broadcast station or another LPFM station.

[65 FR 7640, Feb. 15, 2000, as amended at 65 FR 67303, Nov. 9, 2000; 65 FR 69458, Nov. 17, 2000]

(a) An LPFM authorization may not be transferred or assigned except for a transfer or assignment that involves:

(1) Less than a substantial change in ownership and control; or

(2) An involuntary assignment of license or transfer of control.

(b) A change in the name of an LPFM licensee where no change in ownership or control is involved may be accomplished by written notification by the licensee to the Commission.

(a) A minor change for an LP100 station authorized under this subpart is limited to transmitter site relocations of 5.6 kilometers or less. A minor change for an LP10 station authorized under this subpart is limited to transmitter site relocations of 3.2 kilometers or less. Minor changes of LPFM stations may include changes in frequency to adjacent or IF frequencies or, upon a technical showing of reduced interference, to any frequency.

(b) The Commission will specify by Public Notice a window filing period for applications for new LPFM stations and major modifications in the facilities of authorized LPFM stations. LPFM applications for new facilities and for major modifications in authorized LPFM stations will be accepted only during the appropriate window. Applications submitted prior to the window opening date identified in the Public Notice will be returned as premature. Applications submitted after the deadline will be dismissed with prejudice as untimely.

(c) Applications subject to paragraph (b) of this section that fail to meet the §73.807 minimum distance separations with respect to all applications and facilities in existence as the date of the pertinent public notice in paragraph (b) of this section other than to LPFM station facilities proposed in applications filed in the same window, will be dismissed without any opportunity to amend such applications.

(d) Following the close of the window, the Commission will issue a Public Notice of acceptance for filing of applications submitted pursuant to paragraph (b) of this section that meet technical and legal requirements and that are not in conflict with any other application filed during the window. Following the close of the window, the Commission also will issue a Public Notice of the acceptance for filing of all applications tentatively selected pursuant to the procedures for mutually exclusive LPFM applications set forth at §73.872. Petitions to deny such applications may be filed within 30 days of such public notice and in accordance with the procedures set forth at §73.3584. A copy of any petition to deny must be served on the applicant.

(e) Minor change LPFM applications may be filed at any time, unless restricted by the staff, and generally, will be processed in the order in which they are tendered. Such applications must meet all technical and legal requirements applicable to new LPFM station applications.

[65 FR 7640, Feb. 15, 2000, as amended at 65 FR 67304, Nov. 9, 2000; 70 FR 39186, July 7, 2005]

Effective Date Note:  At 70 FR 39186, July 7, 2005, in §73.870, paragraph (a) was revised. This paragraph contains information collection and recordkeeping requirements and will not become effective until approval has been given by the Office of Management and Budget.

§ 73.871   Amendment of LPFM broadcast station applications.

(a) New and major change applications may be amended without limitation during the pertinent filing window.

(b) Amendments that would improve the comparative position of new and major change applications will not be accepted after the close of the pertinent filing window.

(c) Only minor amendments to new and major change applications will be accepted after the close of the pertinent filing window. Subject to the provisions of this section, such amendments may be filed as a matter of right by the date specified in the FCC's Public Notice announcing the acceptance of such applications. For the purposes of this section, minor amendments are limited to:

(1) Site relocations of 3.2 kilometers or less for LP10 stations;

(2) Site relocations of 5.6 kilometers or less for LP100 stations;

(3) Changes in ownership where the original party or parties to an application retain more than a 50 percent ownership interest in the application as originally filed; and

(4) Other changes in general and/or legal information.

(d) Unauthorized or untimely amendments are subject to return by the FCC's staff without consideration.

[66 FR 23863, May 10, 2001, as amended at 70 FR 39186, July 7, 2005]

Effective Date Note:  At 70 FR 39186, July 7, 2005, in §73.871, paragraph (c) was revised. This paragraph contains information collection and recordkeeping requirements and will not become effective until approval has been given by the Office of Management and Budget.

§ 73.872   Selection procedure for mutually exclusive LPFM applications.

(a) Following the close of each window for new LPFM stations and for modifications in the facilities of authorized LPFM stations, the Commission will issue a public notice identifying all groups of mutually exclusive applications. Such applications will be awarded points to determine the tentative selectee. Unless resolved by settlement pursuant to paragraph (e) of this section, the tentative selectee will be the applicant within each group with the highest point total under the procedure set forth in this section, except as provided in paragraphs (c) and (d) of this section .

(b) Each mutually exclusive application will be awarded one point for each of the following criteria, based on application certification that the qualifying conditions are met:

(1) Established community presence. An applicant must, for a period of at least two years prior to application, have been physically headquartered, have had a campus, or have had seventy-five percent of its board members residing within 10 miles of the coordinates of the proposed transmitting antenna. Applicants claiming a point for this criterion must submit the documentation set forth in the application form at the time of filing their applications.

(2) Proposed operating hours. The applicant must pledge to operate at least 12 hours per day.

(3) Local program origination. The applicant must pledge to originate locally at least eight hours of programming per day. For purposes of this criterion, local origination is the production of programming, by the licensee, within ten miles of the coordinates of the proposed transmitting antenna.

(c) Voluntary time-sharing. If mutually exclusive applications have the same point total, any two or more of the tied applicants may propose to share use of the frequency by submitting, within 30 days of the release of a public notice announcing the tie, a time-share proposal. Such proposals shall be treated as amendments to the time-share proponents' applications, and shall become part of the terms of the station license. Where such proposals include all of the tied applications, all of the tied applications will be treated as tentative selectees; otherwise, time-share proponents' points will be aggregated to determine the tentative selectees.

(1) Time-share proposals shall be in writing and signed by each time-share proponent, and shall satisfy the following requirements:

(i) The proposal must specify the proposed hours of operation of each time-share proponent;

(ii) The proposal must not include simultaneous operation of the time-share proponents; and (iii) Each time-share proponent must propose to operate for at least 10 hours per week.

(2) Where a station is licensed pursuant to a time-sharing proposal, a change of the regular schedule set forth therein will be permitted only where a written agreement signed by each time-sharing licensee and complying with requirements in paragraphs (c)(1)(i) through (iii) of this section is filed with the Commission, Attention: Audio Division, Media Bureau, prior to the date of the change.

(d) Successive license terms. (1) If a tie among mutually exclusive applications is not resolved through time-sharing in accordance with paragraph (c) of this section, the tied applications will be reviewed for acceptability and applicants with tied, grantable applications will be eligible for equal, successive, non-renewable license terms of no less than one year each for a total combined term of eight years, in accordance with §73.873. Eligible applications will be granted simultaneously, and the sequence of the applicants' license terms will be determined by the sequence in which they file applications for licenses to cover their construction permits based on the day of filing, except that eligible applicants proposing same-site facilities will be required, within 30 days of written notification by the Commission staff, to submit a written settlement agreement as to construction and license term sequence. Failure to submit such an agreement will result in the dismissal of the applications proposing same-site facilities and the grant of the remaining, eligible applications.

(2) Groups of more than eight tied, grantable applications will not be eligible for successive license terms under this section. Where such groups exist, the staff will dismiss all but the applications of the eight entities with the longest established community presences, as provided in paragraph (b)(1) of this section. If more than eight tied, grantable applications remain, the applicants must submit, within 30 days of written notification by the Commission staff, a written settlement agreement limiting the group to eight. Failure to do so will result in dismissal of the entire application group.

(e) Mutually exclusive applicants may propose a settlement at any time during the selection process after the release of a public notice announcing the mutually exclusive groups. Settlement proposals must include all of the applicants in a group and must comply with the Commission's rules and policies regarding settlements, including the requirements of §§73.3525, 73.3588, and 73.3589. Settlement proposals may include time-share agreements that comply with the requirements of paragraph (c) of this section, provided that such agreements may not be filed for the purpose of point aggregation outside of the thirty-day period set forth in paragraph (c) of this section.

[65 FR 7640, Feb.15, 2000, as amended at 65 FR 67304, Nov. 9, 2000; 67 FR 13232, Mar. 21, 2002]

(a) Initial licenses for LPFM stations not subject to successive license terms will be issued for a period running until the date specified in §73.1020 for full service stations operating in the LPFM station's state or territory, or if issued after such date, determined in accordance with §73.1020.

(b) The station license period issued under the successive license term tiebreaker procedures will be determined pursuant to §73.872(d) and shall be for the period specified in the station license.

(c) The license of an LPFM station that fails to transmit broadcast signals for any consecutive 12-month period expires as a matter of law at the end of that period, notwithstanding any provision, term, or condition of the license to the contrary.

The following procedures and restrictions apply to licensee modifications of authorized broadcast transmission system facilities.

(a) The following changes are prohibited:

(1) Those that would result in the emission of signals outside of the authorized channel exceeding limits prescribed for the class of service.

(2) Those that would cause the transmission system to exceed the equipment performance measurements prescribed in §73.508.

(b) The following changes may be made only after the grant of a construction permit application on FCC Form 318.

(1) Any construction of a new tower structure for broadcast purposes, except for replacement of an existing tower with a new tower of identical height and geographic coordinates.

(2) Any change in station geographic coordinates, including coordinate corrections and any move of the antenna to another tower structure located at the same coordinates.

(3) Any change in antenna height more than 2 meters above or 4 meters below the authorized value.

(4) Any change in channel.

(c) The following LPFM modifications may be made without prior authorization from the Commission. A modification of license application (FCC Form 319) must be submitted to the Commission within 10 days of commencing program test operations pursuant to §73.1620. For applications filed pursuant to paragraph (c)(1) of this section, the modification of license application must contain an exhibit demonstrating compliance with the Commission's radiofrequency radiation guidelines. In addition, applications solely filed pursuant to paragraphs (c)(1) or (c)(2) of this section, where the installation is located within 3.2 km of an AM tower or is located on an AM tower, an exhibit demonstrating compliance with §73.1692 is also required.

(1) Replacement of an antenna with one of the same or different number of antenna bays, provided that the height of the antenna radiation center is not more than 2 meters above or 4 meters below the authorized values. Program test operations at the full authorized ERP may commence immediately upon installation pursuant to §73.1620(a)(1).

(2) Replacement of a transmission line with one of a different type or length which changes the transmitter operating power (TPO) from the authorized value, but not the ERP, must be reported in a license modification application to the Commission.

(3) Changes in the hours of operation of stations authorized pursuant to time-share agreements in accordance with §73.872.

The licensee of each LPFM station must maintain a station log. Each log entry must include the time and date of observation and the name of the person making the entry. The following information must be entered in the station log:

(a) Any extinguishment or malfunction of the antenna structure obstruction lighting, adjustments, repairs, or replacement to the lighting system, or related notification to the FAA. See §§17.48 and 73.49 of this chapter.

(b) Brief explanation of station outages due to equipment malfunction, servicing, or replacement;

(c) Operations not in accordance with the station license; and

(d) EAS weekly log requirements set forth in §11.61(a)(1)(v) of this chapter.

[65 FR 67304, Nov. 9, 2000]

(a) The licensee of a broadcast station shall make the station available for inspection by representatives of the FCC during the station's business hours, and at any time it is in operation. In the course of an inspection or investigation, an FCC representative may require special equipment or program tests.

(b) Station records and logs shall be made available for inspection or duplication at the request of the FCC or its representatives. Such logs or records may be removed from the licensee's possession by an FCC representative or, upon request, shall be mailed by the licensee to the FCC by either registered mail, return receipt requested, or certified mail, return receipt requested. The return receipt shall be retained by the licensee as part of the station records until such records or logs are returned to the licensee. A receipt shall be furnished when the logs or records are removed from the licensee's possession by an FCC representative and this receipt shall be retained by the licensee as part of the station records until such records or logs are returned to the licensee. When the FCC has no further need for such records or logs, they shall be returned to the licensee. The provisions of this rule shall apply solely to those station logs and records that are required to be maintained by the provisions of this part.

(1) Where records or logs are maintained as the official records of a recognized law enforcement agency and the removal of the records from the possession of the law enforcement agency will hinder its law enforcement activities, such records will not be removed pursuant to this section if the chief of the law enforcement agency promptly certifies in writing to the FCC that removal of the logs or records will hinder law enforcement activities of the agency, stating insofar as feasible the basis for his decision and the date when it can reasonably be expected that such records will be released to the FCC.

An LPFM licensee may not retransmit, either terrestrially or via satellite, the signal of a full-power radio broadcast station.

General EEO policy. Equal employment opportunity shall be afforded by all LPFM licensees and permittees to all qualified persons, and no person shall be discriminated against because of race, color , religion, national origin, or sex.

(a) The rules in this subpart are common to all AM, FM, TV and Class A TV broadcast services, commercial and noncommercial.

(b) Rules in part 73 applying exclusively to a particular broadcast service are contained in the following: AM, subpart A; FM, subpart B; Noncommercial Educational FM, subpart C; TV, subpart E; LPFM, subpart G; and Class A TV, subpart J.

(c) Certain provisions of this subpart apply to International Broadcast Stations (subpart F, part 73), LPFM (subpart G, part 73), and Low Power TV, TV Translator and TV Booster Stations (subpart G, part 74) where the rules for those services so provide.

(d) The provisions of this part applying to licensees also apply to holders of construction permits (permittees).

[43 FR 32781, July 28, 1978, as amended at 52 FR 31399, Aug. 20, 1987; 65 FR 7648, Feb. 15, 2000; 65 FR 30003, May 10, 2000]

Certain rules applicable to broadcast services, some of which are also applicable to other services, are set forth in the following Parts of the FCC Rules and Regulations.

(a) Part 1, “Practice and Procedure.”

(1) Subpart A, “General Rules of Practice and Procedure”. (§§1.1 to 1.120).

(2) Subpart B, “Hearing Proceedings”. (§§1.201 to 1.364)

(3) Subpart C, “Rulemaking Proceedings”. (§§1.399 to 1.430).

(4) Subpart G, “Schedule of Statutory Charges and Procedures for Payment”. (§§1.1101 to 1.1117.)

(5) Subpart H, “Ex Parte Communications”. (§§1.1200 to 1.1216).

(6) Subpart I, “Procedures Implementing the National Environmental Policy Act of 1969”. (§§1.1301 to 1.1319).

(7) Subpart P, “Implementation of the Anti-Drug Abuse Act of 1988”. (§§1.2001–1.2003.)

(8) Subpart Q, “Competitive Bidding Proceedings” (§§1.2101–1.2112).

(9) Part 1, Subpart W of this chapter, “FCC Registration Number”. (§§1.8001–1.8005.)

(b) Part 2, “Frequency Allocations and Radio Treaty Matters, General Rules and Regulations”, including Subparts A, “Terminology”; B, “Allocation, Assignments and Use of Radio Frequencies”; C, “Emissions”; D, “Call Signs and Other Forms of Identifying Radio Transmissions”; and J, “Equipment Authorization Procedures”.

(c) [Reserved]

(d) Part 17, “Construction, Marking and Lighting of Antenna Structures”.

(e) Part 74, “Experimental, Auxiliary and Special Broadcast and Other Program Distributional Services” including:

(1) Subpart A, “Experimental Broadcast Stations”;

(2) Subpart D, “Remote Pickup Broadcast Stations”;

(3) Subpart E, “Aural Broadcast Auxiliary Stations”;

(4) Subpart F, “Television Broadcast Auxiliary Stations”;

(5) Subpart G, “Low Power TV, TV Translator and TV Booster Stations”;

(6) Subpart H, “Low Power Auxiliary Stations”;

(7) Subpart L, “FM Broadcast Translator Stations and FM Broadcast Booster Stations”.

[53 FR 2498, Jan. 28, 1988, as amended at 57 FR 48333, Oct. 23, 1992; 60 FR 55480, Nov. 1, 1995; 63 FR 48622, Sept. 11, 1998; 66 FR 47896, Sept. 14, 2001; 69 FR 72043, Dec. 10, 2004]

The Commission or its representatives may, in writing, require from any applicant, permittee, or licensee written statements of fact relevant to a determination whether an application should be granted or denied, or to a determination whether a license should be revoked, or to any other matter within the jurisdiction of the Commission, or, in the case of a proceeding to amend the FM or Television Table of Allotments, require from any person filing an expression of interest, written statements of fact relevant to that allotment proceeding. Any such statements of fact are subject to the provisions of §1.17 of this chapter.

[68 FR 15098, Mar. 28, 2003]

(a) Initial licenses for broadcast stations will ordinarily be issued for a period running until the date specified in this section for the State or Territory in which the station is located. If issued after such date, it will run to the next renewal date determined in accordance with this section. Both radio and TV broadcasting stations will ordinarily be renewed for 8 years. However, if the FCC finds that the public interest, convenience and necessity will be served thereby, it may issue either an initial license or a renewal thereof for a lesser term. The time of expiration of normally issued initial and renewal licenses will be 3 a.m., local time, on the following dates and thereafter at 8-year intervals for radio and TV broadcast stations located in:

(1) Maryland, District of Columbia, Virginia and West Virginia:

(i) Radio stations, October 1, 1995.

(ii) Television stations, October 1, 1996.

(2) North Carolina and South Carolina:

(i) Radio stations, December 1, 1995.

(ii) Television stations, December 1, 1996.

(3) Florida, Puerto Rico and the Virgin Islands:

(i) Radio stations, February 1, 1996.

(ii) Television stations, February 1, 1997.

(4) Alabama and Georgia:

(i) Radio stations, April 1, 1996.

(ii) Television stations, April 1, 1997.

(5) Arkansas, Louisiana and Mississippi:

(i) Radio stations, June 1, 1996.

(ii) Television stations, June 1, 1997.

(6) Tennessee, Kentucky and Indiana:

(i) Radio stations, August 1, 1996.

(ii) Television stations, August 1, 1997.

(7) Ohio and Michigan:

(i) Radio stations, October 1, 1996.

(ii) Television stations, October 1, 1997.

(8) Illinois and Wisconsin:

(i) Radio stations, December 1, 1996.

(ii) Television stations, December 1, 1997.

(9) Iowa and Missouri:

(i) Radio stations, February 1, 1997.

(ii) Television stations, February 1, 1998.

(10) Minnesota, North Dakota, South Dakota, Montana and Colorado:

(i) Radio stations, April 1, 1997.

(ii) Television stations, April 1, 1998.

(11) Kansas, Oklahoma and Nebraska:

(i) Radio stations, June 1, 1997.

(ii) Television stations, June 1, 1998.

(12) Texas:

(i) Radio stations, August 1, 1997.

(ii) Television stations, August 1, 1998.

(13) Wyoming, Nevada, Arizona, Utah, New Mexico and Idaho:

(i) Radio stations, October 1, 1997.

(ii) Television stations, October 1, 1998.

(14) California:

(i) Radio stations, December 1, 1997.

(ii) Television stations, December 1, 1998.

(15) Alaska, American Samoa, Guam, Hawaii, Mariana Islands, Oregon and Washington:

(i) Radio stations, February 1, 1998.

(ii) Television stations, February 1, 1999.

(16) Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont:

(i) Radio stations, April 1, 1998.

(ii) Television stations, April 1, 1999.

(17) New Jersey and New York:

(i) Radio stations, June 1, 1998.

(ii) Television stations, June 1, 1999.

(18) Delaware and Pennsylvania:

(i) Radio stations, August 1, 1998.

(ii) Television stations, August 1, 1999.

(b) For the cutoff date for the filing of applications mutually exclusive with renewal applications that are filed on or before May 1, 1995 and for the deadline for filing petitions to deny renewal applications, see §73.3516(e).

(c) The license of a broadcasting station that fails to transmit broadcast signals for any consecutive 12-month period expires as a matter of law at the end of that period, notwithstanding any provision, term, or condition of the license to the contrary.

(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154, 155, 303))

[49 FR 4382, Feb. 6, 1984, as amended at 52 FR 25604, July 8, 1987; 59 FR 63051, Dec. 7, 1994; 61 FR 18291, Apr. 25, 1996; 61 FR 28767, June 6, 1996; 62 FR 5347, Feb. 5, 1997]

(a)(1) Radio astronomy and radio research installations. In order to minimize harmful interference at the National Radio Astronomy Observatory site located at Green, Pocahontas County, West Virginia, and at the Naval Radio Research Observatory at Sugar Grove, Pendleton County, West Virginia, a licensee proposing to operate a short-term broadcast auxiliary station pursuant to §74.24, and any applicant for authority to construct a new broadcast station, or for authority to make changes in the frequency, power, antenna height, or antenna directivity of an existing station within the area bounded by 39°15' N on the north, 78°30' W on the east, 37°30' N on the south, and 80°30' W on the west, shall notify the Interference Office, National Radio Astronomy Observatory, P.O. Box 2, Green Bank, West Virginia 24944. Telephone: (304) 456–2011. The notification shall be in writing and set forth the particulars of the proposed station, including the geographical coordinates of the antenna, antenna height, antenna directivity if any, proposed frequency, type of emission and power. The notification shall be made prior to, or simultaneously with, the filing of the application with the Commission. After receipt of such applications, the FCC will allow a period of 20 days for comments or objections in response to the notifications indicated. If an objection to the proposed operation is received during the 20-day period from the National Radio Astronomy Observatory for itself, or on behalf of the Naval Radio Research Observatory, the FCC will consider all aspects of the problem and take whatever action is deemed appropriate.

(2) Any applicant for a new permanent base or fixed station authorization to be located on the islands of Puerto Rico, Desecheo, Mona, Vieques, and Culebra, or for a modification of an existing authorization which would change the frequency, power, antenna height, directivity, or location of a station on these islands and would increase the likelihood of the authorized facility causing interference, shall notify the Interference Office, Arecibo Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612, in writing or electronically, of the technical parameters of the proposal. Applicants may wish to consult interference guidelines, which will be provided by Cornell University. Applicants who choose to transmit information electronically should e-mail to: [email protected].

(i) The notification to the Interference Office, Arecibo Observatory shall be made prior to, or simultaneously with, the filing of the application with the Commission. The notification shall state the geographical coordinates of the antenna (NAD–83 datum), antenna height above ground, ground elevation at the antenna, antenna directivity and gain, proposed frequency and FCC Rule Part, type of emission, and effective radiated power.

(ii) After receipt of such applications, the Commission will allow the Arecibo Observatory a period of 20 days for comments or objections in response to the notification indicated. The applicant will be required to make reasonable efforts to resolve or mitigate any potential interference problem with the Arecibo Observatory and to file either an amendment to the application or a modification application, as appropriate. The Commission shall determine whether an applicant has satisfied its responsibility to make reasonable efforts to protect the Observatory from interference.

(b) Radio receiving installations. Protection for Table Mountain Radio Receiving Zone, Boulder County, Colorado: Applicants for a station authorization to operate in the vicinity of Boulder County, Colorado under this Part are advised to give due consideration, prior to filing applications, to the need to protect the Table Mountain Radio Receiving Zone from harmful interference. These are the research laboratories of the Department of Commerce, Boulder County, Colorado. To prevent degradation of the present ambient radio signal level at the site, the Department of Commerce seeks to ensure that the field strengths of any radiated signals (excluding reflected signals) received on this 1800 acre site (within the area bounded by 40°09'10" N Latitude on the north, 105°13'31" W Longitude on the east, 40°07'05" N Latitude on the south, and 105°15'13" W Longitude on the west) resulting from new assignments (other than mobile stations) or from the modification of relocation of existing facilities do not exceed the following values:

(1) Advance consultation is recommended particularly for those applicants who have no reliable data which indicates whether the field strength or power flux density figures in the above table would be exceeded by their proposed radio facilities (except mobile stations). In such instances, the following is a suggested guide for determining whether coordination is recommended:

(i) All stations within 2.4 km (1.5 statute miles);

(ii) Stations within 4.8 km (3 statute miles) with 50 watts or more effective radiated power (ERP) in the primary plane polarization in the azimuthal direction of the Table Mountain Radio Receiving Zone;

(iii) Stations within 16 km (10 statute miles) with 1 kW or more ERP in the primary plane of polarization in the azimuthal direction of Table Mountain Receiving Zone;

(iv) Stations within 80 km (50 statute miles) with 25 kW or more ERP in the primary plane polarization in the azimuthal direction of Table Mountain Receiving Zone.

(2) Applicants concerned are urged to communicate with the Radio Frequency Management Coordinator, Department of Commerce, Research Support Services, NOAA R/E5X2, Boulder Laboratories, Boulder, CO 80303; telephone (303) 497–6548, in advance of filing their applications with the Commission.

(3) The Commission will not screen applications to determine whether advance consultation has taken place. However, applicants are advised that such consultation can avoid objectimns from the Department of Commerce or proceedings to modify any authorization which may be granted which, in fact, delivers a signal at the site in excess of the field strength specified herein.

(c) Protection for Federal Communications Commission monitoring stations. (1) Applicants in the vicinity of a FCC monitoring station for a radio station authorization to operate new transmitting facilities or changed transmitting facilities which would increase the field strength produced over the monitoring station in excess of that previously authorized are advised to give consideration, prior to filing applications, to the possible need to protect the FCC stations from harmful interference. Geographical coordinates of the facilities which require protection are listed in §0.121(c) of the FCC rules. Applications for stations (except mobile stations) which will produce on any frequency a direct wave fundamental field strength of greater than 10 mV/m in the authorized bandwidth of service (−65.8 dBW/m² power flux density assuming a free space characteristic impedance of 120 π ohms) at the referenced coordinates, may be examined to determine extent of possible interference. Depending on the theoretical field strength value and existing root-sum-square or other ambient radio field signal levels at the indicated coordinates, a clause protecting the monitoring station may be added to the station authorization.

(2) In the event that calculated value of expected field exceeds 10 mV/m (−65.8 dBW/m² ) at the reference coordinates, or if there is any question whether field strength levels might exceed the threshold value, advance consultation with the FCC to discuss any protection necessary should be considered. Prospective applicants may communicate with: Chief, Compliance and Information Bureau, Federal Communications Commission, Washington, DC 20554, Telephone (202) 632–6980.

(3) Advance consultation is suggested particularly for those applicants who have no reliable data which indicates whether the field strength or power flux density figure indicated would be exceeded by their proposed radio facilities (except mobile stations). In such instances, the following is a suggested guide for determining whether an applicant should coordinate:

(i) All stations within 2.4 kilometers (1.5 statute miles);

(ii) Stations within 4.8 kilometers (3 statute miles) with 50 watts or more average effective radiated power (ERP) in the primary plane of polarization in the azimuthal direction of the Monitoring Stations.

(iii) Stations within 16 kilometers (10 statute miles) with 1 kW or more average ERP in the primary plane of polarization in the azimuthal direction of the Monitoring Station;

(iv) Stations within 80 kilometers (50 statute miles) with 25 kW or more average ERP in the primary plane of polarization in the azimuthal direction of the Monitoring Station;

(4) Advance coordination for stations operating above 1000 MHz is recommended only where the proposed station is in the vicinity of a monitoring station designated as a satellite monitoring facility in §0.121(c) of the Commission's Rules and also meets the criteria outlined in paragraphs (b) (2) and (3) of this section.

(5) The Commission will not screen applications to determine whether advance consultation has taken place. However, applicants are advised that such consultation can avoid objections from the Federal Communications Commission or modification of any authorization which will cause harmful interference.

[43 FR 32782, July 28, 1978, as amended at 44 FR 77167, Dec. 31, 1979; 47 FR 9221, Mar. 4, 1982; 50 FR 39003, Sept. 26, 1985; 52 FR 25867, July 9, 1987; 52 FR 36879, Oct. 1, 1987; 52 FR 37789, Oct. 9, 1987; 56 FR 64872, Dec. 12, 1991; 61 FR 8477, Mar. 5, 1996; 62 FR 55532, Oct. 27, 1997; 63 FR 70048, Dec. 18, 1998; 70 FR 31373, June 1, 2005]

Each AM, FM, TV and Class A TV broadcast station will be licensed to the principal community or other political subdivision which it primarily serves. This principal community (city, town or other political subdivision) will be considered to be the geographical station location.

[65 FR 30003, May 10, 2000]

(a) Except for those stations described in paragraph (b) of this section, each AM, FM, and TV broadcast station shall maintain a main studio at one of the following locations:

(1) Within the station's community of license;

(2) At any location within the principal community contour of any AM, FM, or TV broadcast station licensed to the station's community of license; or

(3) Within twenty-five miles from the reference coordinates of the center of its community of license as described in §73.208(a)(1).

Note to paragraph (a): The principal community contour of AM stations that simulcast on a frequency in the 535–1605 kHz band and on a frequency in the 1605–1705 kHz band shall be the 5 mV/m contour of the lower band operation during the term of the simultaneous operating authority. Upon termination of the 535–1605 kHz band portion of the dual frequency operation, the principal community contour shall become the 5 mV/m of the remaining operation in the 1605–1705 kHz band.

(b) The following stations are not required to maintain their main studio at the locations described in paragraph (a) of this section.

(1) AM stations licensed as synchronous amplifier transmitters (“AM boosters”) or,

(2) AM, FM, or TV stations, when good cause exists for locating the main studio at a location other than that described in paragraph (a) of this section, and when so doing would be consistent with the operation of the station in the public interest.

(c) Each Class A television station shall maintain a main studio at a location within the station's predicted Grade B contour, as defined in §73.683 and calculated using the method specified in §73.684. With respect to a group of commonly controlled stations, Class A stations whose predicted Grade B contours are physically contiguous to each other may locate their main studio within any of these contours. If a Class A station is one of a group of commonly controlled Class A stations, but its predicted Grade B contour is not physically contiguous to that of another Class A station in the commonly owned group, its main studio shall be located within its own predicted Grade B contour. Alternatively, a Class A television station shall maintain a main studio at the site used by the station as of November 29, 1999.

(d) Relocation of the main studio may be made:

(1) From one point to another within the locations described in paragraph (a) or (c) of this section, or from a point outside the locations specified in paragraph (a) or (c) to one within those locations, without specific FCC authority, but notification to the FCC in Washington shall be made promptly.

(2) Written authority to locate a main studio outside the locations specified in paragraph (a) or (c) of this section for the first time must be obtained from the Audio Division, Media Bureau for AM and FM stations, or the Video Division for TV and Class A television stations before the studio may be moved to that location. Where the main studio is already authorized at a location outside those specified in paragraph (a) or (c) of this section, and the licensee or permittee desires to specify a new location also located outside those locations, written authority must also be received from the Commission prior to the relocation of the main studio. Authority for these changes may be requested by filing a letter with an explanation of the proposed changes with the appropriate division. Licensees or permittees should also be aware that the filing of such a letter request does not imply approval of the relocation request, because each request is addressed on a case-by-case basis. A filing fee is required for commercial AM, FM, TV or Class A TV licensees or permittees filing a letter request under the section (see §1.1104 of this chapter).

(e) Each AM, FM, TV and Class A TV broadcast station shall maintain a local telephone number in its community of license or a toll-free number.

[63 FR 49497, Sept. 16, 1998, as amended at 65 FR 30003, May 10, 2000; 66 FR 21690, May 1, 2001; 67 FR 13232, Mar. 21, 2002]

(a) In transferring a broadcast station, the licensee may retain no right of reversion of the license, no right to reassignment of the license in the future, and may not reserve the right to use the facilities of the station for any period whatsoever.

(b) No license, renewal of license, assignment of license or transfer of control of a corporate licensee will be granted or authorized if there is a contract, arrangement or understanding, express or implied, pursuant to which, as consideration or partial consideration for the assignment or transfer, such rights, as stated in paragraph (a) of this section, are retained.

(c) Licensees and/or permittees authorized to operate in the 535–1605 kHz and in the 1605–1705 kHz band pursuant to the Report and Order in MM Docket No. 87–267 will not be permitted to assign or transfer control of the license or permit for a single frequency during the period that joint operation is authorized.

(d) Authorizations awarded pursuant to the noncommercial educational point system in subpart K are subject to the holding period in §73.7005. Applications for an assignment or transfer filed prior to the end of the holding period must demonstrate the factors enumerated therein.

[44 FR 58720, Oct. 11, 1979, as amended at 56 FR 64872, Dec. 12, 1991; 65 FR 36378, June 8, 2000]

(a) When regularly required. Broadcast station identification announcements shall be made:

(1) At the beginning and ending of each time of operation, and

(2) Hourly, as close to the hour as feasible, at a natural break in program offerings. Television and Class A television broadcast stations may make these announcements visually or aurally.

(b) Content. (1) Official station identification shall consist of the station's call letters immediately followed by the community or communities specified in its license as the station's location; Provided, That the name of the licensee, the station's frequency, the station's channel number, as stated on the station's license, and/or the station's network affiliation may be inserted between the call letters and station location. DTV stations choosing to include the station's channel number in the station identification must use the station's major channel number and may distinguish multicast program streams. For example, a station with major channel number 26 may use 26.1 to identify an HDTV program service and 26.2 to identify an SDTV program service. No other insertion between the station's call letters and the community or communities specified in its license is permissible.

(2) A station may include in its official station identification the name of any additional community or communities, but the community to which the station is licensed must be named first.

(c) Channel—(1) General. Except as otherwise provided in this paragraph, in making the identification announcement the call letters shall be given only on the channel, or channels in the case of a broadcaster that is multicasting more than a single channel, identified thereby.

(2) Simultaneous AM (535–1605 kHz) and AM (1605–1705 kHz broadcasts. If the same licensee operates an AM broadcast station in the 535–1605 kHz band and an AM broadcast station in the 1605–1705 kHz band with both stations licensed to the same community and simultaneously broadcasts the same programs over the facilities of both such stations, station identification announcements may be made jointly for both stations for periods of such simultaneous operations.

(3) Satellite operation. When programming of a broadcast station is rebroadcast simultaneously over the facilities of a satellite station, the originating station may make identification announcements for the satellite station for periods of such simultaneous operation.

(i) In the case of a television broadcast station, such announcements, in addition to the information required by paragraph (b)(1) of this section, shall include the number of the channel on which each station is operating.

(ii) In the case of aural broadcast stations, such announcements, in addition to the information required by paragraph (b)(1) of this section, shall include the frequency on which each station is operating.

(d) Subscription television stations (STV). The requirements for official station identification applicable to TV stations will apply to Subscription TV stations except, during STV-encoded programming such station identification is not required. However, a station identification announcement will be made immediately prior to and following the encoded Subscription TV program period.

[34 FR 19762, Dec. 17, 1969, as amended at 37 FR 23726, Nov. 8, 1972; 39 FR 6707, Feb. 22, 1974; 39 FR 9442, Mar. 11, 1974; 41 FR 29394, July 16, 1976; 47 FR 3791, Jan. 27, 1982; 48 FR 51308, Nov. 8, 1983; 56 FR 64872, Dec. 12, 1991; 65 FR 30003, May 10, 2000; 69 FR 59535, Oct. 4, 2004]

All written comments and suggestions received from the public by licensees of commercial AM, FM, TV and Class A TV broadcast stations regarding operation of their station shall be maintained in the local public inspection file, unless the letter writer has requested that the letter not be made public or when the licensee feels that it should be excluded from the public inspection file because of the nature of its content, such as a defamatory or obscene letter.

(a) Letters shall be retained in the local public inspection file for three years from the date on which they are received by the licensee.

(b) Letters received by TV and Class A TV licensees shall be placed in one of the following separated subject categories: programming or non-programming. If comments in a letter relate to both categories, the licensee shall file it under the category to which the writer has given greater attention.

[65 FR 30003, May 10, 2000]

Before recording a telephone conversation for broadcast, or broadcasting such a conversation simultaneously with its occurrence, a licensee shall inform any party to the call of the licensee's intention to broadcast the conversation, except where such party is aware, or may be presumed to be aware from the circumstances of the conversation, that it is being or likely will be broadcast. Such awareness is presumed to exist only when the other party to the call is associated with the station (such as as employee or part-time reporter), or where the other party originates the call and it is obvious that it is in connection with a program in which the station customarily broadcasts telephone conversations.

[35 FR 7733, May 20, 1970]

(a) The term rebroadcast means reception by radio of the programs or other transmissions of a broadcast or any other type of radio station, and the simultaneous or subsequent retransmission of such programs or transmissions by a broadcast station.

(1) As used in this section, “program” includes any complete programs or part thereof.

(2) The transmission of a program from its point of origin to a broadcast station entirely by common carrier facilities, whether by wire line or radio, is not considered a rebroadcast.

(3) The broadcasting of a program relayed by a remote pickup broadcast station is not considered a rebroadcast.

(b) No broadcast station may retransmit the program, or any part thereof, of another U.S. broadcast station without the express authority of the originating station. A copy of the written consent of the licensee originating the program must be kept by the licensee of the station retransmitting such program and made available to the FCC upon request.

(1) Stations originating emergency communications under a State EAS plan are considered to have conferred rebroadcast authority to other participating stations.

(2) Permission must be obtained from the originating station to rebroadcast any subsidiary communications transmitted by means of a multiplex subcarrier or telecommunications service on the vertical blanking interval or in the visual signal of a television signal.

(3) Programs originated by the Voice of America (VOA) and the Armed Forces Radio and Television Services (AFRTS) cannot, in general, be cleared for domestic rebroadcast, and may therefore be retransmitted only by special arrangements among the parties concerned.

(4) Except as otherwise provided by international agreement, programs originated by foreign broadcast stations may be retransmitted without the consent of the originating station.

(c) The transmissions of non-broadcast stations may be rebroadcast under the following conditions:

(1) Messages originated by privately-owned non-broadcast stations other than those in the Amateur and Citizens Band (CB) Radio Services may be broadcast only upon receipt of prior permission from the non-broadcast licensee. Additionally, messages transmitted by common carrier stations may be rebroadcast only upon prior permission of the originator of the message as well as the station licensee.

(2) Except as provided in paragraph (d) of this section, messages originated entirely by non-broadcast stations owned and operated by the Federal Government may be rebroadcast only upon receipt of prior permission from the government agency originating the messages.

(3) Messages originated by stations in the amateur and Citizens Band (CB) radio services may be rebroadcast at the discretion of broadcast station licensees.

(4) Emergency communications originated under a State EAS plan.

(d) The rebroadcasting of time signals originated by the Naval Observatory and the National Bureau of Standards and messages from the National Weather Service stations is permitted without specific authorization under the following procedures:

(1) Naval Observatory Time Signals. (i) The time signals rebroadcast must be obtained by direct radio reception from a naval radio station, or by land line circuits.

(ii) Announcement of the time signal must be made without reference to any commercial activity.

(iii) Identification of the Naval Observatory as the source of the time signal must be made by an announcement, substantially as follows: “With the signal, the time will be . . . courtesy of the U.S. Naval Observatory.”

(iv) Schedules of time signal broadcasts may be obtained upon request from the Superintendent, U.S. Naval Observatory, Washington, DC 20390.

(2) National Bureau of Standards Time Signals. (i) Time signals for rebroadcast must be obtained by direct radio reception from a National Bureau of Standards (NBS) station.

(ii) Use of receiving and rebroadcasting equipment must not delay the signals by more than 0.05 second.

(iii) Signals must be rebroadcast live, not from tape or other recording.

(iv) Voice or code announcements of the call signs of NBS stations are not to be rebroadcast.

(v) Identification of the origin of the service and the source of the signals must be made by an announcement substantially as follows: “At the tone, 11 hours 25 minutes Coordinated Universal Time. This is a rebroadcast of a continous service furnished by the National Bureau of Standards, Ft. Collins, Colo.” No commercial sponsorship of this announcement is permitted and none may be implied.

(vi) Schedules of time signal broadcasts may be obtained from, and notice of use of NBS time signals for rebroadcast must be forwarded semiannually to:

National Bureau of Standards, Radio Stations WWV/WWVB, 2000 East County Road 58, Ft. Collins, Colorado 80524.

(vii) In the rebroadcasting of NBS time signals, announcements will not state that they are standard frequency transmissions. Voice announcements of Coordinated Universal Time are given in voice every minute. Each minute, except the first of the hour, begins with an 0.8 second long tone of 1000 hertz at WWV and 1200 hertz tone at WWVH. The first minute of every hour begins with an 0.8 second long tone of 1500 hertz at both stations. This tone is followed by a 3-second pause, than the announcement, “National Bureau of Standards Time.” This is followed by another 3-second pause before station identification. This arrangement allows broadcast stations sufficient time to retransmit the hour time tone and the words “National Bureau of Standards Time” either by manual or automatic switching.

(viii) Time signals or scales made up from integration of standard frequency signals broadcast from NBS stations may not be designated as national standard scales of time or attributed to the NBS as originator. For example, if a broadcasting station transmits time signals obtained from a studio clock which is periodically calibrated against the NBS time signals from WWV or WWVH, such signals may not be announced as NBS standard time or as having been originated by the NBS.

(3) National Weather Service Messages. (i) Messages of the National Weather Service must be rebroadcast within 1 hour of receipt.

(ii) If advertisements are given in connection with weather rebroadcast, these advertisements must not directly or indirectly convey an endorsement by the U.S. Government of the products or services so advertised.

(iii) Credit must be given to indicate that the rebroadcast message originates with the National Weather Service.

[44 FR 36040, June 20, 1979, as amended at 45 FR 26065, Apr. 17, 1980; 48 FR 28456, June 22, 1983; 50 FR 25246, June 18, 1985; 59 FR 67102, Dec. 28, 1994; 61 FR 36305, July 10, 1996]

(a) Any taped, filmed or recorded program material in which time is of special significance, or by which an affirmative attempt is made to create the impression that it is occurring simultaneously with the broadcast, shall be announced at the beginning as taped, filmed or recorded. The language of the announcement shall be clear and in terms commonly understood by the public. For television stations, the announcement may be made visually or aurally.

(b) Taped, filmed, or recorded announcements which are of a commercial, promotional or public service nature need not be identified as taped, filmed or recorded.

[37 FR 23726, Nov. 8, 1972]

Unless specifically designated as “standard (non-advanced)” or “advanced,” all references to time contained in this part, and in license documents and other authorizations issued thereunder shall be understood to mean local time; i.e., the time legally observed in the community.

[39 FR 26736, July 23, 1974]

(a) For the purpose of this section, dual-language broadcasting shall be understood to mean the telecasting of a program in one language with the simultaneous transmission, on the main channel of a participating FM broadcast station, of companion sound track information in a different language.

(b) Television and Class A television licensees in Puerto Rico may enter into dual-language time purchase agreements with FM broadcast licensees, subject to the following conditions:

(1) All such agreements shall be reduced to writing and retained by the licensee for possible Commission inspection, in accordance with §73.3613 of this chapter.

(2) All such agreements shall specify that the FM licensee will monitor sound track material with a view to rejecting any material deemed to be inappropriate or objectionable for broadcast exposure.

(3) No television, Class A television, or FM broadcast station may devote more than 15 hours per week to dual-language broadcasting, nor may more than three (3) hours of such programming be presented on any given day.

(4) Noncommercial educational television broadcast stations shall take all necessary precautions to assure that the entire operation is conducted on a noncommercial basis and otherwise in accordance with §73.621 of this part.

[40 FR 17259, Apr. 18, 1975, as amended at 49 FR 33663, Aug. 24, 1984; 50 FR 40016, Oct. 1, 1985; 65 FR 30003, May 10, 2000]

(a) No licensee of an AM, FM, television, or Class A television broadcast station, except as in paragraph (c) of this section, shall broadcast any advertisement of or information concerning any lottery, gift enterprise, or similar scheme, offering prizes dependent in whole or in part upon lot or chance, or any list of the prizes drawn or awarded by means of any such lottery, gift enterprise or scheme, whether said list contains any part or all of such prizes. (18 U.S.C. 1304, 62 Stat. 763).

(b) The determination whether a particular program comes within the provisions of paragraph (a) of this section depends on the facts of each case. However, the Commission will in any event consider that a program comes within the provisions of paragraph (a) of this section if in connection with such program a prize consisting of money or other thing of value is awarded to any person whose selection is dependent in whole or in part upon lot or chance, if as a condition of winning or competing for such prize, such winner or winners are required to furnish any money or other thing of value or are required to have in their possession any product sold, manufactured, furnished or distributed by a sponsor of a program broadcast on the station in question. (See 21 FCC 2d 846).

(c) The provisions of paragraphs (a) and (b) of this section shall not apply to an advertisement, list of prizes or other information concerning:

(1) A lottery conducted by a State acting under the authority of State law which is broadcast by a radio or television station licensed to a location in that State or any other State which conducts such a lottery. (18 U.S.C. 1307(a); 102 Stat. 3205).

(2) Fishing contests exempted under 18 U.S. Code 1305 (not conducted for profit, i.e., all receipts fully consumed in defraying the actual costs of operation).

(3) Any gaming conducted by an Indian Tribe pursuant to the Indian Gaming Regulatory Act (25 U.S.C. 2701 et seq.)

(4) A lottery, gift enterprise or similar scheme, other than one described in paragraph (c)(1) of this section, that is authorized or not otherwise prohibited by the State in which it is conducted and which is:

(i) Conducted by a not-for-profit organization or a governmental organization (18 U.S.C. 1307(a); 102 Stat. 3205); or

(ii) Conducted as a promotional activity by a commercial organization and is clearly occasional and ancillary to the primary business of that organization. (18 U.S.C. 1307(a); 102 Stat. 3205).

(d)(1) For purposes of paragraph (c) of this section, “lottery” means the pooling of proceeds derived from the sale of tickets or chances and allotting those proceeds or parts thereof by chance to one or more chance takers or ticket purchasers. It does not include the placing or accepting of bets or wagers on sporting events or contests.

(2) For purposes of paragraph (c)(4)(i) of this section, the term “not-for-profit organization” means any organization that would qualify as tax exempt under section 501 of the Internal Revenue Code of 1986.

[40 FR 6210, Feb. 10, 1975, as amended at 45 FR 6401, Jan. 28, 1980; 54 FR 20856, May 15, 1989; 55 FR 18888, May 7, 1990; 65 FR 30003, May 10, 2000]

(a) When a broadcast station transmits any matter for which money, service, or other valuable consideration is either directly or indirectly paid or promised to, or charged or accepted by such station, the station, at the time of the broadcast, shall announce:

(1) That such matter is sponsored, paid for, or furnished, either in whole or in part, and

(2) By whom or on whose behalf such consideration was supplied: Provided, however, That “service or other valuable consideration” shall not include any service or property furnished either without or at a nominal charge for use on, or in connection with, a broadcast unless it is so furnished in consideration for an identification of any person, product, service, trademark, or brand name beyond an identification reasonably related to the use of such service or property on the broadcast.

(i) For the purposes of this section, the term “sponsored” shall be deemed to have the same meaning as “paid for.”

(ii) In the case of any television political advertisement concerning candidates for public office, the sponsor shall be identified with letters equal to or greater than four percent of the vertical picture height that air for not less than four seconds.

(b) The licensee of each broadcast station shall exercise reasonable diligence to obtain from its employees, and from other persons with whom it deals directly in connection with any matter for broadcast, information to enable such licensee to make the announcement required by this section.

(c) In any case where a report has been made to a broadcast station as required by section 507 of the Communications Act of 1934, as amended, of circumstances which would have required an announcement under this section had the consideration been received by such broadcast station, an appropriate announcement shall be made by such station.

(d) In the case of any political broadcast matter or any broadcast matter involving the discussion of a controversial issue of public importance for which any film, record, transcription, talent, script, or other material or service of any kind is furnished, either directly or indirectly, to a station as an inducement for broadcasting such matter, an announcement shall be made both at the beginning and conclusion of such broadcast on which such material or service is used that such film, record, transcription, talent, script, or other material or service has been furnished to such station in connection with the transmission of such broadcast matter: Provided, however, That in the case of any broadcast of 5 minutes' duration or less, only one such announcement need be made either at the beginning or conclusion of the broadcast.

(e) The announcement required by this section shall, in addition to stating the fact that the broadcast matter was sponsored, paid for or furnished, fully and fairly disclose the true identity of the person or persons, or corporation, committee, association or other unincorporated group, or other entity by whom or on whose behalf such payment is made or promised, or from whom or on whose behalf such services or other valuable consideration is received, or by whom the material or services referred to in paragraph (d) of this section are furnished. Where an agent or other person or entity contracts or otherwise makes arrangements with a station on behalf of another, and such fact is known or by the exercise of reasonable diligence, as specified in paragraph (b) of this section, could be known to the station, the announcement shall disclose the identity of the person or persons or entity on whose behalf such agent is acting instead of the name of such agent. Where the material broadcast is political matter or matter involving the discussion of a controversial issue of public importance and a corporation, committee, association or other unincorporated group, or other entity is paying for or furnishing the broadcast matter, the station shall, in addition to making the announcement required by this section, require that a list of the chief executive officers or members of the executive committee or of the board of directors of the corporation, committee, association or other unincorporated group, or other entity shall be made available for public inspection at the location specified by the licensee under §73.3526 of this chapter. If the broadcast is originated by a network, the list may, instead, be retained at the headquarters office of the network or at the location where the originating station maintains its public inspection file under §73.3526 of this chapter. Such lists shall be kept and made available for a period of two years.

(f) In the case of broadcast matter advertising commercial products or services, an announcement stating the sponsor's corporate or trade name, or the name of the sponsor's product, when it is clear that the mention of the name of the product constitutes a sponsorship identification, shall be deemed sufficient for the purpose of this section and only one such announcement need be made at any time during the course of the broadcast.

(g) The announcement otherwise required by section 317 of the Communications Act of 1934, as amended, is waived with respect to the broadcast of “want ad” or classified advertisements sponsored by an individual. The waiver granted in this paragraph shall not extend to a classified advertisement or want ad sponsorship by any form of business enterprise, corporate or otherwise. Whenever sponsorship announcements are omitted pursuant to this paragraph, the licensee shall observe the following conditions:

(1) Maintain a list showing the name, address, and (where available) the telephone number of each advertiser;

(2) Make this list available to members of the public who have a legitimate interest in obtaining the information contained in the list. Such list must be retained for a period of two years after broadcast.

(h) Any announcement required by section 317(b) of the Communications Act of 1934, as amended, is waived with respect to feature motion picture film produced initially and primarily for theatre exhibition.

Note: The waiver heretofore granted by the Commission in its Report and Order adopted November 16, 1960 (FCC 60–1369; 40 F.C.C. 95), continues to apply to programs filmed or recorded on or before June 20, 1963, when §73.654, the predecessor television rule, went into effect.

(i) Commission interpretations in connection with the provisions of the sponsorship identification rules are contained in the Commission's Public Notice, entitled “Applicability of Sponsorship Identification Rules,” dated May 6, 1963 (40 F.C.C. 141), as modified by Public Notice, dated April 21, 1975 (FCC 75–418). Further interpretations are printed in full in various volumes of the Federal Communications Commission Reports.

[40 FR 18400, Apr. 28, 1975, as amended at 46 FR 13907, Feb. 24, 1981; 49 FR 4211, Feb. 3, 1984; 49 FR 33663, Aug. 24, 1984; 50 FR 32417, Aug. 12, 1985; 57 FR 8279, Mar. 9, 1992]

(a) The provisions of part 17 of this chapter (Construction, Marking, and Lighting of Antenna Structures), requires certain antenna structures to be painted and/or lighted in accordance with part 17.

(b) The owner of each antenna structure is responsible for ensuring that the structure, if required, is painted and/or illuminated in accordance with part 17 of this chapter. In the event of default by the owner, each licensee or permittee shall be responsible for ensuring that the structure complies with applicable painting and lighting requirements.

[61 FR 4367, Feb. 6, 1996]

The following requirements and specifications shall apply to indicating instruments used by broadcast stations:

(a) Linear scale instruments:

(1) Length of scale shall not be less than 2.3 inches (5.8 cm).

(2) Accuracy shall be at least 2 percent of the full scale reading.

(3) The maximum rating of the meter shall be such that it does not read off scale during modulation or normal operation.

(4) Scale shall have at least 40 divisions.

(5) Full scale reading shall not be greater than five times the minimum normal indication.

(b) Instruments having square-law scales:

(1) Meet the requirements of paragraphs (a) (1), (2), and (3) of this section for linear scale instruments.

(2) Full scale reading shall not be greater than three times the minimum normal indication.

(3) No scale division above one-third full scale reading shall be greater than one-thirtieth of the full scale reading. (Example: An ammeter meeting requirement (1) having full scale reading of 6 amperes is acceptable for reading currents from 2 to 6 amperes, provided no scale division between 2 and 6 amperes is greater than one-thirtieth of 6 amperes, 0.2 ampere.)

(c) Instruments having logarithmic scales:

(1) Meet the requirements of paragraphs (a) (1), (2), and (3) of this section for linear scale instruments.

(2) Full scale reading shall not be greater than five times the minimum normal indication.

(3) No scale division above one-fifth full scale reading (in watts) shall be greater than one-thirtieth of the full scale reading. (Example: A wattmeter meeting requirement (3) having full scale reading of 1,500 watts is acceptable for reading power from 300 to 1,500 watts, provided no scale division between 300 and 1,500 watts is greater than one-thirtieth of 1,500 watts or 50 watts.)

(d) Instruments having expanded scales:

(1) Shall meet the requirements of paragraphs (a) (1), (2), and (3) of this section for linear scale instruments.

(2) Full scale reading shall not be greater than five times the minimum normal indication.

(3) No scale division above one-fifth full scale reading shall be greater than one-fiftieth of the full scale reading. (Example: An ammeter meeting the requirement (1) is acceptable for indicating current from 1 to 5 amperes, provided no division between 1 and 5 amperes is greater than one-fiftieth of 5 amperes, 0.1 ampere.)

(e) Digital meters, printers, or other numerical readout devices may be used in addition to or in lieu of indicating instruments meeting the specifications of paragraphs (a), (b), (c), and (d) of this section. The readout of the device must include at least three digits and must indicate the value of the parameter being read to an accuracy of 2%. The multiplier, if any, to be applied to the reading of each parameter must be indicated at the operating position.

(f) No instrument which has been broken or appears to be damaged or defective, or the accuracy of which is questionable shall be used, until it has been checked, and if necessary repaired and recalibrated by the manufacturer or qualified instrument repair service. Repaired instruments shall not be used unless a certificate of calibration has been provided showing that the instrument conforms to the manufacturer's specifications for accuracy.

[41 FR 36818, Sept. 1, 1976; 41 FR 43152, Sept. 30, 1976, as amended at 51 FR 2707, Jan. 21, 1986]

A licensee that broadcasts or advertises information about a contest it conducts shall fully and accurately disclose the material terms of the contest, and shall conduct the contest substantially as announced or advertised. No contest description shall be false, misleading or deceptive with respect to any material term.

Note 1: For the purposes of this rule:

Note 2: In general, the time and manner of disclosure of the material terms of a contest are within the licensee's discretion. However, the obligation to disclose the material terms arises at the time the audience is first told how to enter or participate and continues thereafter. The material terms should be disclosed periodically by announcements broadcast on the station conducting the contest, but need not be enumerated each time an announcement promoting the contest is broadcast. Disclosure of material terms in a reasonable number of announcements is sufficient. In addition to the required broadcast announcements, disclosure of the material terms may be made in a non-broadcast manner.

Note 3: This rule is not applicable to licensee-conducted contests not broadcast or advertised to the general public or to a substantial segment thereof, to contests in which the general public is not requested or permitted to participate, to the commercial advertisement of non-licensee-conducted contests, or to a contest conducted by a non-broadcast division of the licensee or by a non-broadcast company related to the licensee.

[41 FR 43152, Sept. 30, 1976]

No licensee or permittee of any broadcast station shall broadcast false information concerning a crime or a catastrophe if:

(a) The licensee knows this information is false;

(b) It is forseeable that broadcast of the information will cause substantial public harm, and

(c) Broadcast of the information does in fact directly cause substantial public harm.

Any programming accompanied by a disclaimer will be presumed not to pose foreseeable harm if the disclaimer clearly characterizes the program as a fiction and is presented in a way that is reasonable under the circumstances.

Note: For purposes of this rule, “public harm” must begin immediately, and cause direct and actual damage to property or to the health or safety of the general public, or diversion of law enforcement or other public health and safety authorities from their duties. The public harm will be deemed foreseeable if the licensee could expect with a significant degree of certainty that public harm would occur. A “crime” is any act or omission that makes the offender subject to criminal punishment by law. A “catastrophe” is a disaster or imminent disaster involving violent or sudden event affecting the public.

[57 FR 28640, June 26, 1992]

(a) The licensee of a broadcast station shall make the station available for inspection by representatives of the FCC during the station's business hours, or at any time it is in operation.

(b) In the course of an inspection or investigation, an FCC representative may require special equipment tests, program tests or operation with nighttime or presunrise facilities during daytime hours pursuant to §0.314, part 0, of the FCC rules.

(c) The following records shall be made available by all broadcast stations upon request by representatives of the FCC.

(1) Equipment performance measurements required by §§73.1590 and 73.1690.

(2) The written designations for chief operators and, when applicable, the contracts for chief operators engaged on a contract basis.

(3) Application for modification of the transmission system made pursuant to §73.1690(c).

(4) Informal statements or drawings depicting any transmitter modification made pursuant to §73.1690(e).

(5) Station logs and special technical records.

(d) Commercial and noncommercial AM stations must make the following information also available upon request by representatives of the FCC.

(1) Copy of the most recent antenna or common-point impedance measurements.

(2) Copy of the most recent field strength measurements made to establish performance of directional antennas required by §73.151.

(3) Copy of the partial directional antenna proofs of performance made in accordance with §73.154 and made pursuant to the following requirements:

(i) Section 73.68, Sampling systems for antenna monitors.

(ii) Section 73.69, Antenna monitors.

(iii) Section 73.61, AM direction antenna field strength measurements.

[43 FR 45846, Oct. 4, 1978; 43 FR 50683, Oct. 31, 1978, as amended at 51 FR 41629, Nov. 18, 1986; 51 FR 44478, Dec. 10, 1986; 57 FR 48333, Oct. 23, 1992]

The following shall be made available to any authorized representative of the FCC upon request:

(a) Station records and logs shall be made available for inspection or duplication at the request of the FCC or its representative. Such logs or records may be removed from the licensee's possession by an FCC representative or, upon request, shall be mailed by the licensee to the FCC by either registered mail, return receipt requested, or certified mail, return receipt requested. The return receipt shall be retained by the licensee as part of the station records until such records or logs are returned to the licensee. A receipt shall be furnished when the logs or records are removed from the licensee's possession by an FCC representative and this receipt shall be retained by the licensee as part of the station records until such records or logs are returned to the licensee. When the FCC has no further need for such records or logs, they shall be returned to the licensee. The provisions of this rule shall apply solely to those station logs and records which are required to be maintained by the provisions of this chapter.

(1) Logs and records stored on microfilm, microfiche or other data-storage systems are subject to the requirements pertaining thereto found in §73.1840(b).

(b) Where records or logs are maintained as the official records of a recognized law enforcement agency and the removal of the records from the possession of the law enforcement agency will hinder its law enforcement activities, such records will not be removed pursuant to this section if the chief of the law enforcement agency promptly certifies in writing to the FCC that removal of the logs or records will hinder law enforcement activities of the agency, stating insofar as feasible the basis for his decision and the date when it can reasonably be expected that such records will be released to the FCC.

(c) The following contracts, agreements, or understandings, which need not be filed with the FCC (per §73.3613, Filing of contracts), must be kept at the station and made available for inspection by any authorized representative of the FCC upon request:

(1) Contracts relating to the sale of broadcast time to “time brokers” for resale.

(2) FM subchannel leasing agreements for subsidiary communications.

(3) Time sales contracts with the same sponsor for 4 or more hours per day, except where the length of the events (such as athletic contests, musical programs, and special events) broadcast pursuant to the contract is not under control of the station.

(4) Contracts with chief operators or other engineering personnel.

[43 FR 45847, Oct. 4, 1978; 43 FR 50683, Oct. 31, 1978, as amended at 45 FR 41151, June 18, 1980; 48 FR 28457, June 22, 1983]

(a) The station license and any other instrument of station authorization shall be posted in a conspicuous place and in such a manner that all terms are visible at the place the licensee considers to be the principal control point of the transmitter.

(b) Posting of the station license and any other instruments of authorization shall be done by affixing them to the wall at thee posting location, or by enclosing them in a binder or folder which is retained at the posting location so that the documents will be readily available and easily accessible.

[60 FR 55480, Nov. 1, 1995]

(a) Emergency situations in which the broadcasting of information is considered as furthering the safety of life and property include, but are not limited to the following: Tornadoes, hurricanes, floods, tidal waves, earthquakes, icing conditions, heavy snows, widespread fires, discharge of toxic gasses, widspread power failures, industrial explosions, civil disorders and school closing and changes in school bus schedules resulting from such conditions. See also §73.3542, Application for Emergency Authorization, for requirements involving emergency situations not covered by this section for which prior operating authority must be requested.

(b) If requested by responsible public officials, a station may, at its discretion, and without further FCC authority, transmit emergency point-to-point messages for the purpose of requesting or dispatching aid and assisting in rescue operations.

(c) If the Emergency Alert System (EAS) is activated for a national emergency while a Local Area or State emergency operation is in progress, the national level EAS operation must take precedence. If, during the broadcasting of Local Area or State emergency information, the EAS codes or Attention Signal described in §11.12 of this chapter are used, the broadcasts are considered as being carried out under a Local Area or State EAS plan.

(d) Any emergency operation undertaken in accordance with this section may be terminated by the FCC if required in the public interest.

(e) Immediately upon cessation of an emergency during which broadcast facilities were used for the transmission of point-to-point messages under paragraph (b) of this section, or when daytime facilities were used during nighttime hours by an AM station in accordance with paragraph (f) of this section, a report in letter form shall be forwarded to the FCC in Washington, DC, setting forth the nature of the emergency, the dates and hours of the broadcasting of emergency information, and a brief description of the material carried during the emergency. A certification of compliance with the noncommercialization provision of paragraph (f) of this section must accompany the report where daytime facilities are used during nighttime hours by an AM station, together with a detailed showing, under the provisisons of that paragraph, that no other broadcast service existed or was adequate.

(f) AM stations may, without further FCC authority, use their full daytime facilities during nighttime hours to broadcast emergency information (examples listed in paragraph (a) of this section), when necessary to the safety of life and property, in dangerous conditions of a general nature and when adequate advance warning cannot be given with the facilities authorized. Because of skywave interference impact on other stations assigned to the same channel, such operation may be undertaken only if regular, unlimited-time service, is non-existent, inadequate from the standpoint of coverage, or not serving the public need. All operation under this paragraph must be conducted on a noncommercial basis. Recorded music may be used to the extent necessary to provide program continuity.

(g) Broadcasting of emergency information shall be confined to the hours, frequencies, powers and modes of operation specified in the station license, except as otherwise provided for AM stations in paragraph (f) of this section.

(h) Any emergency information transmitted by a TV or Class A TV station in accordance with this section shall be transmitted both aurally and visually or only visually. TV and Class A TV stations may use any method of visual presentation which results in a legible message conveying the essential emergency information. Methods which may be used include, but are not necessarily limited to, slides, electronic captioning, manual methods (e.g., hand printing) or mechanical printing processes. However, when an emergency operation is being conducted under a national, State or Local Area Emergency Alert System (EAS) plan, emergency information shall be transmitted both aurally and visually unless only the EAS codes are transmitted as specified in §11.51(b) of this chapter.

[43 FR 45847, Oct. 4, 1978, as amended at 50 FR 30947, July 31, 1985; 59 FR 67102, Dec. 28, 1994; 60 FR 56000, Nov. 6, 1995; 65 FR 30003, May 10, 2000]

Broadcast stations may be operated as either attended (where a designated person is responsible for the proper operation of the transmitting apparatus either at the transmitter site, a remote control point or an ATS control point) or unattended (where highly stable equipment or automated monitoring of station operating parameters is employed). No prior FCC approval is required to operate a station in the unattended mode. Regardless of which method of station operation is employed, licensees must employ procedures which will ensure compliance with Part 11 of this chapter, the rules governing the Emergency Alert System (EAS).

[60 FR 55481, Nov. 1, 1995]

(a) Each licensee is responsible for maintaining and operating its broadcast station in a manner which complies with the technical rules set forth elsewhere in this part and in accordance with the terms of the station authorization.

(b) The licensee must designate a chief operator in accordance with §73.1870. The licensee may designate one or more technically competent persons to adjust the transmitter operating parameters for compliance with the technical rules and the station authorization.

(1) Persons so authorized by the licensee may make such adjustments directly at the transmitter site or by using control equipment at an off-site location.

(2) The transmitter control personnel must have the capability to turn the transmitter off at all times. If the personnel are at a remote location, the control system must provide this capability continuously or must include an alternate method of acquiring control that can satisfy the requirement of paragraph (d) of this section that operation be terminated within 3 minutes.

(c) The licensee must establish monitoring procedures and schedules for the station and the indicating instruments employed must comply with §73.1215.

(1) Monitoring procedures and schedules must enable the licensee to determine compliance with §73.1560 regarding operating power and AM station mode of operation, §73.1570 regarding modulation levels, and, where applicable, §73.1213 regarding antenna tower lighting, and §73.69 regarding the parameters of an AM directional antenna system.

(2) Monitoring equipment must be periodically calibrated so as to provide reliable indications of transmitter operating parameters with a known degree of accuracy. Errors inherent in monitoring equipment and the calibration procedure must be taken into account when adjusting operating parameters to ensure that the limits imposed by the technical rules and the station authorization are not exceeded.

(d) In the event that a broadcast station is operating in a manner that is not in compliance with the technical rules set forth elsewhere in this part or the terms of the station authorization, and the condition is not listed in paragraph (e) of this section, broadcast operation must be terminated within three hours.

(1) Examples of conditions that require termination of operation include excessive power or excessive modulation.

(2) Additional examples for AM stations are any mode of operation not specified by the station license for the pertinent time of day or hours of operation and any condition of antenna parameters or monitoring points out of the tolerances specified elsewhere in this part or by the station's instrument of authorization. For these conditions, operation must be terminated within three minutes unless antenna input power is reduced sufficiently to eliminate any excess radiation.

(3) For AM stations using directional arrays, additional procedures apply when array operating parameters are at variance, monitoring points exceed specified limits, or authorized directional mode capability is lost. See §73.62, Directional antenna system tolerances; §73.158, Directional antenna monitoring points; and §73.1680(b), Emergency antennas.

(e) If a broadcast station is operating in a manner that is not in compliance with one of the following technical rules, operation may continue if the station complies with relevant alternative provisions in the specified rule section.

(1) AM directional antenna system tolerances, see §73.62;

(2) AM directional antenna monitoring points, see §73.158;

(3) TV visual waveform, see §73.691(b);

(4) Reduced power operation, see §73.1560(d);

(5) Reduced modulation level, see §73.1570(a);

(6) Emergency antennas, see §73.1680.

(f) The transmission system must be maintained and inspected in accordance with §73.1580.

(g) Whenever a transmission system control point is established at a location other than the main studio or transmitter, a letter of notification of that location must be sent to the FCC in Washington, DC, Attention: Audio Division (radio) or Video Division (television), Media Bureau, within 3 days of the initial use of that point. The letter should include a list of all control points in use, for clarity. This notification is not required if responsible station personnel can be contacted at the transmitter or studio site during hours of operation.

(h) The licensee must ensure that the station is operated in compliance with Part 11 of this chapter, the rules governing the Emergency Alert System (EAS).

[60 FR 55481, Nov. 1, 1995, as amended at 63 FR 33877, June 22, 1998; 67 FR 13232, Mar. 21, 2002]

The licensee of an AM, FM, TV or Class A TV station is responsible for assuring that at all times the station operates within tolerances specified by applicable technical rules contained in this part and in accordance with the terms of the station authorization. Any method of complying with applicable tolerances is permissible. The following are typical methods of transmission system operation:

(a) Attended operation. (1) Attended operation consists of ongoing supervision of the transmission facilities by a station employee or other person designated by the licensee. Such supervision may be accomplished by either:

(i) Direct supervision and control of transmission system parameters by a person at the transmitter site; or

(ii) Remote control of the transmission system by a person at the main studio or other location. The remote control system must provide sufficient transmission system monitoring and control capability so as to ensure compliance with §73.1350.

(2) A station may also be monitored and controlled by an automatic transmission system (ATS) that is configured to contact a person designated by the licensee in the event of a technical malfunction. An automatic transmission system consists of monitoring devices, control and alarm circuitry, arranged so that they interact automatically to operate the station's transmitter and maintain technical parameters within licensed values.

(3) A hybrid system containing some remote control and some ATS features is also permissible.

(4) In the case of remote control or ATS operation, not every station parameter need be monitored or controlled if the licensee has good reason to believe that its stability is so great that its monitoring and control are unnecessary.

(b) Unattended operation. Unattended operation is either the absence of human supervision or the substitution of automated supervision of a station's transmission system for human supervision. In the former case, equipment is employed which is expected to operate within assigned tolerances for extended periods of time. The latter consists of the use of a self-monitoring or ATS-monitored and controlled transmission system that, in lieu of contacting a person designated by the licensee, automatically takes the station off the air within three hours of any technical malfunction which is capable of causing interference.

[60 FR 55481, Nov. 1, 1995, as amended at 65 FR 30003, May 10, 2000]

(a) Licensees of broadcast stations may obtain experimental authorizations to conduct technical experimentation directed toward improvement of the technical phases of operation and service, and for such purposes may use a signal other than the normal broadcast program signal.

(b) Experimental authorizations may be requested by filing an informal application with the FCC in Washington, DC, describing the nature and purpose of the experimentation to be conducted, the nature of the experimental signal to be transmitted, and the proposed schedule of hours and duration of the experimentation. Experimental authorizations shall be posted with the station license.

(c) Experimental operations are subject to the following conditions:

(1) The authorized power of the station may not be exceeded, except as specifically authorized for the experimental operations.

(2) Emissions outside the authorized bandwidth must be attenuated to the degree required for the particular type of station.

(3) The experimental operations may be conducted at any time the station is authorized to operate, but the minimum required schedule of programming for the class and type of station must be met. AM stations also may conduct experimental operations during the experimental period (12 midnight local time to local sunrise) and at additional hours if permitted by the experimental authorization provided no interference is caused to other stations maintaining a regular operating schedule within such period(s).

(4) If an experimental authorization permits the use of additional facilities or hours of operation for experimental purposes, no sponsored programs or commercial announcements may be transmitted during such experimentation.

(5) The licensee may transmit regularly scheduled programming concurrently with the experimental transmission if there is no significant impairment of service.

(6) No charges may be made, either directly or indirectly, for the experimentation; however, normal charges may be made for regularly scheduled programming transmitted concurrently with the experimental transmissions.

(d) The FCC may request a report of the research, experimentation and results at the conclusion of the experimental operation.

[43 FR 32783, July 28, 1978]

(a) A special field test authorization may be issued to conduct field strength surveys to aid in the selection of suitable sites for broadcast transmission facilities, determine coverage areas, or to study other factors influencing broadcast signal propagation. The applicant for the authorization must be qualified to hold a license under section 303(1)(l) of the Communications Act.

(b) Requests for authorizations to operate a transmitter under a Special field test authorization must be in writing using an informal application in letter form, signed by the applicant and including the following information:

(1) Purpose, duration and need for the survey.

(2) Frequency, transmitter output powers and time of operation.

(3) A brief description of the test antenna system, its estimated effective radiated field and height above ground or average terrain, and the geographic coordinates of its proposed location(s).

(c) Operation under a special field test authorization is subject to the following conditions:

(1) No objectionable interference will result to the operation of other authorized radio services; in this connection, the power requested shall not exceed that necessary for the purposes of the test.

(2) The carriers will be unmodulated except for the transmission of a test-pattern on a visual TV transmitter, and for hourly voice station identification on aural AM, FM and TV transmitters.

(3) The transmitter output power or antenna input power may not exceed those specified in the test authorization and the operating power must be maintained at a constant value for each phase of the tests.

(4) The input power to the final amplifier stage, and the AM antenna current or the FM or TV transmitter output power must be observed and recorded at half hour intervals and at any time that the power is adjusted or changed. Copies of these records must be submitted to the FCC with the required report.

(5) The test equipment may not be permanently installed, unless such installation has been separately authorized. Mobile units are not deemed permanent installations.

(6) Test transmitters must be operated by or under the immediate direction of an operator holding a commercial radio operator license (any class, unless otherwise endorsed).

(7) A report, containing the measurements, their analysis and other results of the survey shall be filed with the FCC in Washington, DC within sixty (60) days following the termination of the test authorization.

(8) The test transmission equipment, installation and operation thereof need not comply with the requirements of FCC rules and standards except as specified in this section if the equipment, installation and operation are consistent with good engineering principles and practices.

(d) A special field test authorization may be modified or terminated by notification from the FCC if in its judgment such action will promote the public interest, convenience and necessity.

[44 FR 58734, Oct. 11, 1979, as amended at 46 FR 35463, July 8, 1981; 49 FR 4211, Feb. 3, 1984; 49 FR 20670, May 16, 1984]

(a) Broadcast stations may be operated for tests and maintenance of their transmitting systems on their assigned frequencies using their licensed operating power and antennas during their authorized hours of operation without specific authorization from the FCC.

(b) Licensees of AM stations may operate for tests and maintenance during the hours from 12 midnight local time to local sunrise, if no interference is caused to other stations maintaining a regular operating schedule within such period. No AM station licensed for “daytime” or “specified hours” of operation may broadcast any regular or scheduled programs during this period of test and maintenance operation.

(c) Licensees of AM stations may obtain special antenna test authorizations, and operate under the provisions described in §73.157, to operate with nighttime facilities during daytime hours in conducting directional antenna field strength and antenna proof of performance measurements.

[43 FR 32783, July 28, 1978, as amended at 45 FR 6401, Jan. 28, 1980]

A portable test station is one that is moved from place to place for making field strength and ground conductivity measurements, for selecting station transmitter sites, and conducting other specialized propagation tests. Portable test stations are not normally used while in motion, and may not be used for the transmission of programs intended to be received by the public.

[43 FR 32783, July 28, 1978]

(a) The carrier frequency of each AM and FM station and the visual carrier frequency and the difference between the visual carrier and the aural carrier or center frequency of each TV and Class A TV station shall be measured or determined as often as necessary to ensure that they are maintained within the prescribed tolerances.

(b) In measuring the carrier frequency, the licensee may use any method or procedure that has sufficient precision to establish that the carrier frequency is within the prescribed departure limits.

(c) The primary standard of frequency for radio frequency measurements is the standard frequency maintained by the National Bureau of Standards or the standard signals of Stations WWV, WWVB, and WWVH of the National Bureau of Standards.

[43 FR 32783, July 28, 1978, as amended at 48 FR 44805, Sept. 30, 1983; 65 FR 30004, May 10, 2000]

(a) AM stations. The departure of the carrier frequency for monophonic transmissions or center frequency for stereophonic transmissions may not exceed ±20 Hz from the assigned frequency.

(b) FM stations. (1) The departure of the carrier or center frequency of an FM station with an authorized transmitter output power more than 10 watts may not exceed ±2000 Hz from the assigned frequency.

(2) The departure of the carrier or center frequency of an FM station with an authorized transmitter output power of 10 watts or less may not exceed ±3000 Hz from the assigned frequency.

(c) TV stations. (1) The departure of the visual carrier frequency of a TV station may not exceed ±1000 Hz from the assigned visual carrier frequency.

(2) The departure of the aural carrier frequency of a TV station may not exceed ±1000 Hz from the actual visual carrier frequency plus exactly 4.5 MHz.

(d) International broadcast stations. The departure of the carrier frequency of an International broadcast station may not exceed 0.0015% of the assigned frequency on which the station is transmitting.

(e) Class A TV stations. The departure of the carrier frequency of Class A TV stations may not exceed the values specified in §74.761 of this chapter. Provided, however, that Class A TV stations licensed to operate with a carrier offset, including those stations licensed with a maximum effective radiated power and/or antenna height greater than the values specified in their initial Class A TV station authorization, must comply with paragraph (c) of this section.

Note to paragraph (e): At a date not later than nine months after release of the Memorandum Opinion and Order on Reconsideration in MM Docket No. 00–10 (the proceeding that established the Class A TV service), all licensed Class A stations must operate with a carrier frequency offset. See Memorandum Opinion and Order on Reconsideration, In the Matter of Establishment of a Class A Television Service, MM Docket No. 00–10, released April 13, 2001.

[44 FR 58734, Oct. 11, 1979; 44 FR 64408, Nov. 7, 1979, as amended at 47 FR 13165, Mar. 29, 1982; 65 FR 30004, May 10, 2000; 67 FR 21691, May 1, 2001]

Effective Date Note:  At 66 FR 21691, May 1, 2001, §73.1545 was amended by revising and adding a note to paragraph (e). This paragraph contains information collection and recordkeeping requirements and will not become effective until approval has been given by the Office of Management and Budget.

§ 73.1560   Operating power and mode tolerances.

(a) AM stations. (1) Except as provided for in paragraph (d) of this section, the antenna input power of an AM station as determined by the procedures specified in §73.51 must be maintained as near as is practicable to the authorized antenna input power and may not be less than 90% nor more than 105% of the authorized power.

(2) Whenever the transmitter of an AM station cannot be placed into the specified operating mode at the time required, transmissions of the station must be immediately terminated. However, if the radiated field at any bearing or elevation does not exceed that permitted for that time of day, operation in the mode with the lesser radiated field may continue under the notification procedures of paragraph (d) of this section.

(b) FM stations. Except as provided in paragraph (d) of this section, the transmitter output power of an FM station, with power output as determined by the procedures specified in §73.267, which is authorized for output power more than 10 watts must be maintained as near as practicable to the authorized transmitter output power and may not be less than 90% nor more than 105% of the authorized power. FM stations operating with authorized transmitter output power of 10 watts or less, may operate at less than the authorized power, but not more than 105% of the authorized power.

(c) TV stations. (1) Except as provided in paragraph (d) of this section, the visual output power of a TV or Class A TV transmitter, as determined by the procedures specified in Sec. 73.664, must be maintained as near as is practicable to the authorized transmitter output power and may not be less than 80% nor more than 110% of the authorized power.

(2) The output power of the aural transmitter shall be maintained to provide an aural carrier ERP not to exceed 22% of the peak authorized visual ERP.

(3) The FCC may specify deviation from the power of tolerance requirements for subscription television operations to the extent it deems necessary to permit proper operation.

(d) Reduced power operation. In the event it becomes technically impossible to operate at authorized power, a broadcast station may operate at reduced power for a period of not more than 30 days without specific authority from the FCC. If operation at reduced power will exceed 10 consecutive days, notification must be made to the FCC in Washington, DC, Attention: Audio Division (radio) or Video Division (television), Media Bureau, not later than the 10th day of the lower power operation. In the event that normal power is restored within the 30 day period, the licensee must notify the FCC of the date that normal operation was restored. If causes beyond the control of the licensee prevent restoration of the authorized power within 30 days, a request for Special Temporary Authority (see §73.1635) must be made to the FCC in Washington, DC for additional time as may be necessary.

[44 FR 58734, Oct. 11, 1979, as amended at 49 FR 22093, May 25, 1984; 49 FR 29069, July 18, 1984; 49 FR 47610, Dec. 6, 1984; 50 FR 26568, June 27, 1985; 50 FR 40015, Oct. 1, 1985; 63 FR 33877, June 22, 1998; 65 FR 30004, May 10, 2000; 67 FR 13232, Mar. 21, 2002]

(a) The percentage of modulation is to be maintained at as high a level as is consistent with good quality of transmission and good broadcast service, with maximum levels not to exceed the values specified in paragraph (b). Generally, the modulation should not be less than 85% on peaks of frequent recurrence, but where lower modulation levels may be required to avoid objectionable loudness or to maintain the dynamic range of the program material, the degree of modulation may be reduced to whatever level is necessary for this purpose, even though under such circumstances, the level may be substantially less than that which produces peaks of frequent recurrence at a level of 85%.

(b) Maximum modulation levels must meet the following limitations:

(1) AM stations. In no case shall the amplitude modulation of the carrier wave exceed 100% on negative peaks of frequent recurrence, or 125% on positive peaks at any time.

(i) AM stations transmitting stereophonic programs not exceed the AM maximum stereophonic transmission signal modulation specifications of stereophonic system in use.

(ii) For AM stations transmitting telemetry signals for remote control or automatic transmission system operation, the amplitude of modulation of the carrier by the use of subaudible tones must not be higher than necessary to effect reliable and accurate data transmission and may not, in any case, exceed 6%.

(2) FM stations. The total modulation must not exceed 100 percent on peaks of frequent reoccurrence referenced to 75 kHz deviation. However, stations providing subsidiary communications services using subcarriers under provisions of §73.319 concurrently with the broadcasting of stereophonic or monophonic programs may increase the peak modulation deviation as follows:

(i) The total peak modulation may be increased 0.5 percent for each 1.0 percent subcarrier injection modulation.

(ii) In no event may the modulation of the carrier exceed 110 percent (82.5 kHz peak deviation).

(3) TV and Class A TV stations. In no case shall the total modulation of the aural carrier exceed 100% on peaks of frequent recurrence, unless some other peak modulation level is specified in an instrument of authorization. For monophonic transmissions, 100% modulation is defined as +/−25 kHz.

(c) If a limiting or compression amplifier is employed to maintain modulation levels, precaution must be taken so as not to substantially alter the dynamic characteristics of programs.

[44 FR 58735, Oct. 11, 1979, as amended at 47 FR 13165, Mar. 29, 1982; 49 FR 14508, Apr. 12, 1984; 49 FR 15081, Apr. 17, 1984; 49 FR 27147, July 2, 1984; 49 FR 47610, Dec. 6, 1984; 49 FR 48312, Dec. 12, 1984; 51 FR 26251, July 22, 1986; 56 FR 64872, Dec. 12, 1991; 65 FR 30004, May 10, 2000]

Each AM, FM, TV and Class A TV station licensee or permittee must conduct periodic complete inspections of the transmitting system and all required monitors to ensure proper station operation.

[65 FR 30004, May 10, 2000]

(a) The licensee of each AM, FM, TV and Class A TV station, except licensees of Class D non-commercial educational FM stations authorized to operate with 10 watts or less output power, must make equipment performance measurements for each main transmitter as follows:

(1) Upon initial installation of a new or replacement main transmitter.

(2) Upon modification of an existing transmitter made under the provisions of §73.1690, Modification of transmission systems, and specified therein.

(3) Installation of AM stereophonic transmission equipment pursuant to §73.128.

(4) Installation of FM subcarrier or stereophonic transmission equipment pursuant to §73.295, §73.297, §73.593 or §73.597.

(5) Installation of TV stereophonic or subcarrier transmission equipment pursuant to §§73.669 and 73.1690.

(6) Annually, for AM stations, with not more than 14 months between measurements.

(7) When required by other provisions of the rules or the station license.

(b) Measurements for spurious and harmonic emissions must be made to show compliance with the transmission system requirements of §73.44 for AM stations; §73.317 for FM stations and §73.687 for TV stations. Measurements must be made under all conditions of modulation expected to be encountered by the station whether transmitting monophonic or stereophonic programs and providing subsidiary communications services.

(c) TV visual equipment performance measurements must be made with the equipment adjusted for normal program operation at the transmitter antenna sampling port to yield the following information:

(1) Field strength or voltage of the lower side-band for a modulating frequency of 1.25 MHz or greater, (including 3.58 MHz for color), and of the upper side-band for a modulating frequency of 4.75 MHz or greater.

(2) Data showing that the waveform of the transmitted signal conforms to that specified by the standards for TV transmissions.

(3) Photographs of a test pattern taken from a receiver or monitor connected to the transmitter output.

(4) Data showing envelope delay characteristics of the radiated signal.

(5) Data showing the attenuation of spurious and harmonic radiation, if, after type acceptance, any changes have been made in the transmitter or associated equipment (filters, multiplexer, etc.) which could cause changes in its radiation products.

(d) The data required by paragraphs (b) and (c) of this section, together with a description of the equipment and procedure used in making the measurements, signed and dated by the qualified person(s) making the measurements, must be kept on file at the transmitter or remote control point for a period of 2 years, and on request must be made available during that time to duly authorized representatives of the FCC.

[47 FR 8589, Mar. 1, 1982, as amended at 51 FR 18450, May 20, 1986; 65 FR 30004, May 10, 2000]

(a) During the process of construction of a new broadcast station, the permittee, after notifying the FCC in Washington, D.C. may, without further authority from the FCC, conduct equipment tests for the purpose of making such adjustments and measurements as may be necessary to assure compliance with the terms of the construction permit, the technical provisions of the application therefore, the rules and regulations and the applicable engineering standards. For AM stations, equipment tests, including either a directional or nondirectional proof of performance required by the construction permit, may be conducted during daytime hours provided that the antenna system is first substantially tuned during the experimental period. The nondirectional proof shall be conducted with power adjusted to 25% of that specified in the permit for the authorized directional facilities or, if applicable, to such higher power as is specified in the same permit for authorized nondirectional facilities. For licensed stations, see §73.1615, Operation During Modification of Facilities; and §73.157, Antenna Testing During Daytime.

(b) The FCC may notify the permittee not to conduct equipment tests or may modify, cancel, suspend, or change the modes of testing or the dates and times for such tests in order to resolve interference complaints or when such action may appear to be in the public interest, convenience, and necessity.

(c) Equipment tests may be continued so long as the construction permit shall remain valid.

(d) The authorization for tests embodied in this section shall not be construed as constituting a license to operate but as a necessary part of construction.

[43 FR 32783, July 28, 1978, as amended at 47 FR 40174, Sept. 13, 1982; 50 FR 30947, July 31, 1985]

When the licensee of an existing AM, FM, TV or Class A TV station is in the process of modifying existing facilities as authorized by a construction permit and determines it is necessary to either discontinue operation or to operate with temporary facilities to continue program service, the following procedures apply:

(a) Licensees holding a construction permit for modification of directional or nondirectional FM, TV or Class A TV or nondirectional AM station facilities may, without specific FCC authority, for a period not exceeding 30 days:

(1) Discontinue operation, or

(2) Operate with temporary facilities to maintain, as nearly as possible, but not exceed, the size of the presently licensed coverage area.

(b) Licensees of an AM station holding a construction permit which involves directional facilities and which does not involve a change in operating frequency may, without specific FCC authority, for a period not exceeding 30 days:

(1) Discontinue operation, or

(2) Operate with reduced power or with parameters at variance from licensed tolerances while maintaining monitoring point field strengths within licensed limits during the period subsequent to the commencement of modifications authorized by the construction permit, or

(3) Operate in a nondirectional mode during the presently licensed hours of directional operation with power reduced to 25% or less of the nominal licensed power, or whatever higher power, not exceeding licensed power, will insure that the radiated field strength specified by the license is not exceeded at any given asimuth for the corresponding hours of directional operation, or

(4) Operate in a nondirectional mode during daytime hours, if not already so licensed, only as necessary to conduct a required nondirectional proof of performance with a power not to exceed 25% of the maximum power authorized by the construction permit for directional operation, or

(5) Operate during daytime hours with either the daytime or nighttime directional pattern and with the power authorized by the construction permit only as necessary to take proof of performance measurements. Operating power shall be promptly reduced to presently licensed level during any significant period of time that these measurements are not being taken. No daytime operation of construction permit directional patterns authorized by this paragraph shall be conducted before such patterns have been substantially tuned during the experimental period.

(6) In the event the directional pattern authorized by the construction permit replaces a licensed directional pattern, the licensee may operate with the substantially adjusted construction permit pattern during the corresponding licensed hours of directional operation with power not exceeding that specified for the licensed pattern.

(c) Such operation or discontinuance of operation in accordance with the provisions of paragraph (a) or (b) of this section may begin upon notification to the FCC in Washington, DC.

(1) Should it be necessary to continue the procedures in either paragraph (a) or (b) of this section beyond 30 days, an informal letter request signed by the licensee or the licensee's representative must be sent to the FCC in Washington, DC. prior to the 30th day.

(2) The license of a broadcasting station that fails to transmit broadcast signals for any consecutive 12-month period expires as a matter of law at the end of that period, notwithstanding any provision, term, or condition of the license or construction permit to the contrary.

(d) Licensees of an AM station holding a construction permit which authorizes both a change in frequency and directional facilities must request and obtain authority from the FCC in Washington, DC. prior to using any new installation authorized by the permit, or using temporary facilities.

(1) The request is to be made at least 10 days prior to the date on which the temporary operation is to commence. The request is to be made by letter which shall describe the operating modes and facilities to be used. Such letter requests shall be signed by the licensee or the licensee's representative.

(2) Discontinuance of operation is permitted upon notification to the FCC In Washington, DC. Should it be necessary to discontinue operation longer than 30 days, an informal letter request, signed by the licensee or the licensee's representatives, must be sent to the FCC in Washington, DC prior to the 30th day.

(e) The FCC may modify or cancel the temporary operation permitted under the provisions of paragraph (a), (b), (c) or (d) of this section without prior notice or right to hearing.

[50 FR 30947, July 31, 1985, as amended at 61 FR 28767, June 6, 1996; 65 FR 30004, May 10, 2000]

(a) Upon completion of construction of an AM, FM, TV or Class A TV station in accordance with the terms of the construction permit, the technical provisions of the application, the rules and regulations and the applicable engineering standards, program tests may be conducted in accordance with the following:

(1) The permittee of a nondirectional AM or FM station, or a nondirectional or directional TV or Class A TV station, may begin program tests upon notification to the FCC in Washington, DC provided that within 10 days thereafter, an application for a license is filed with the FCC in Washington, DC.

(2) The permittee of an FM station with a directional antenna system must file an application for license on FCC Form 302–FM requesting authority to commence program test operations at full power with the FCC in Washington, D.C. This license application must be filed at least 10 days prior to the date on which full power operations are desired to commence. The application for license must contain any exhibits called for by conditions on the construction permit. The staff will review the license application and the request for program test authority and issue a letter notifying the applicant whether full power operation has been approved. Upon filing of the license application and related exhibits, and while awaiting approval of full power operation, the FM permittee may operate the directional antenna at one half (50%) of the authorized effective radiated power. Alternatively, the permittee may continue operation with its existing licensed facilities pending the issuance of program test authority at the full effective radiated power by the staff.

(3) FM licensees replacing a directional antenna pursuant to §73.1690 (c)(2) without changes which require a construction permit (see §73.1690(b)) may immediately commence program test operations with the new antenna at one half (50%) of the authorized ERP upon installation. If the directional antenna replacement is an EXACT duplicate of the antenna being replaced (i.e., same manufacturer, antenna model number, and measured composite pattern), program tests may commence with the new antenna at the full authorized power upon installation. The licensee must file a modification of license application on FCC Form 302–FM within 10 days of commencing operations with the newly installed antenna, and the license application must contain all of the exhibits required by §73.1690(c)(2). After review of the modification-of-license application to cover the antenna change, the Commission will issue a letter notifying the applicant whether program test operation at the full authorized power has been approved for the replacement directional antenna.

(4) The permittee of an AM station with a directional antenna system must file an application for license on FCC Form 302–AM requesting program test authority with the FCC in Washington, DC at least ten (10) days prior to the date on which it desires to commence program test operations. The application must provide an AM directional antenna proof of performance, containing the exhibits required by §73.186. After review of the application to cover the construction permit, the Commission will issue a letter notifying the applicant whether program test operations may commence. Program test operations may not commence prior to issuance of staff approval.

(5) Except for permits subject to successive license terms, the permittee of an LPFM station may begin program tests upon notification to the FCC in Washington, DC, provided that within 10 days thereafter, an application for license is filed. Program tests may be conducted by a licensee subject to mandatory license terms only during the term specified on such licensee's authorization.

(b) The Commission reserves the right to revoke, suspend, or modify program tests by any station without right of hearing for failure to comply adequately with all terms of the construction permit or the provisions of §73.1690(c) for a modification of license application, or in order to resolve instances of interference. The Commission may, at its discretion, also require the filing of a construction permit application to bring the station into compliance the Commission's rules and policies.

(c) Unless sooner suspended or revoked, the program test authority continues valid during FCC consideration of the application for license, and during this period further extension of the construction permit is not required. Program test authority shall be automatically terminated by final determination upon the application for station license.

(d) All operation under program test authority shall be in strict compliance with the rules governing broadcast stations and in strict accordance with representations made in the application for license pursuant to which the tests were authorized.

(e) Acceptance by the FCC of notification of the station of program tests, or the granting of program test authority by the FCC, is not to be construed by the permittee as approval by the FCC of the application for station license.

(f) The licensee of a UHF TV station which is not in operation on, but assigned to, the same allocated channel which a 1000 watt UHF translator station is authorized to use (see §73.3516, “Specification of facilities”), shall notify the licensee of the translator station, in writing, at least 10 days prior to commencing or resuming operation. The TV station licensee shall also certify to the FCC in Washington, DC that such advance notice has been given to the translator station licensee.

(g) Reports required. In their application for a license to cover a construction permit and on the first anniversary of the commencement of program tests, applicants for new broadcast facilities that were granted after designation for a comparative hearing as a result of a post designation settlement or a decision favoring them after comparative consideration must report.

(1) Any deviations from comparative proposals relating to integration of ownership and management and diversification of the media of mass communciation contained in their application for a construction permit at the time such application was granted; and

(2) Any deviations from an active/passive ownership structure proposed in their application for a construction permit at the time such application was granted.

(3) The reports referred to in paragraphs (g)(1) and (2) of this section shall not be required in any case in which the order granting the application relieved the applicant of the obligation to adhere to such proposals.

[43 FR 32784, July 28, 1978, as amended at 45 FR 6401, Jan. 28, 1980; 47 FR 28388, June 30, 1982; 49 FR 38132, Sept. 27, 1984; 56 FR 795, Jan. 9, 1991; 56 FR 25639, June 5, 1991; 57 FR 48333, Oct. 23, 1992; 62 FR 51059, Sept. 30, 1997; 65 FR 7648, Feb. 15, 2000; 65 FR 30004, May 10, 2000]

(a) A special temporary authorization (STA) is the authority granted to a permittee or licensee to permit the operation of a broadcast facility for a limited period at a specified variance from the terms of the station authorization or requirements of the FCC rules applicable to the particular class of station.

(1) A request for a STA should be filed with FCC in Washington, DC at least 10 days prior to the date of the proposed operation.

(2) The request is to be made by letter and shall fully describe the proposed operation and the necessity for the requested STA. Such letter requests shall be signed by the licensee or the licensee's representative.

(3) A request for a STA necessitated by unforeseen equipment damage or failure may be made without regard to the procedural requirements of this section (e.g. via telegram or telephone). Any request made pursuant to this paragraph shall be followed by a written confirmation request conforming to the requirements of paragraph (a)(2) of this section. Confirmation requests shall be submitted within 24 hours. (See also §73.1680 Emergency Antennas).

(4) An STA may be granted for an initial period not to exceed 180 days. A limited number of extensions of such authorizations may be granted for additional periods not exceeding 180 days per extension. An STA necessitated by technical or equipment problems, however, may, in practice, be granted for an initial period not to exceed 90 days with a limited number of extensions not to exceed 90 days per extension. The permittee or licensee must demonstrate that any further extensions requested are necessary and that all steps to resume normal operation are being undertaken in an expeditions and timely fashion. The license of a broadcasting station that fails to transmit broadcast signals for any consecutive 12-month period expires as a matter of law at the end of that period, notwithstanding any STA or provision, term, or condition of the license to the contrary.

(5) Certain rules specify special considerations and procedures in situations requiring an STA or permit temporary operation at variance without prior authorization from the FCC when notification is filed as prescribed in the particular rules. See §73.62, Directional antenna system tolerances; §73.157, Antenna testing during daytime; §73.158, Directional antenna monitoring points; §73.691, Visual modulation monitoring; §73.1250, Broadcasting emergency information; §73.1350, Transmission system operation; §73.1560, Operating power and mode tolerances; §73.1570, Modulation levels: AM, FM, TV and Class A TV aural; §73.1615, Operation during modification of facilities; §73.1680, Emergency antennas; and §73.1740, Minimum operating schedule.

(b) An STA may be modified or cancelled by the FCC without prior notice or right to hearing.

(c) No request by an AM station for temporary authority to extend its hours of operation beyond those authorized by its regular authorization will be accepted or granted by the FCC except in emergency situations conforming with the requirements of §73.3542, Application for Emergency Authorization. See also §73.1250, Broadcasting Emergency Information.

[50 FR 30948, July 31, 1985, as amended at 58 FR 51250, Oct. 1, 1993; 60 FR 55482, Nov. 1, 1995; 61 FR 28767, June 6, 1996; 65 FR 30004, May 10, 2000]

(a) The rules in this part 73, and authorizations for which they provide, are subject to compliance with the international obligations and undertakings of the United States. Accordingly, all provisions in this part 73 are subject to compliance with applicable requirements, restrictions, and procedures accepted by the United States that have been established by or pursuant to treaties or other international agreements, arrangements, or understandings to which the United States is a signatory, including applicable annexes, protocols, resolutions, recommendations and other supplementing documents associated with such international instruments.

(b) The United States is a signatory to the following treaties and other international agreements that relate, in whole or in part, to AM, FM or TV broadcasting:

(1) The following instruments of the International Telecommunication Union:

(i) Constitution.

(ii) Convention.

(iii) Radio Regulations.

(2) Regional Agreements for the Broadcasting Service in Region 2:

(i) MF Broadcasting 535–1605 kHz, Rio de Janeiro, 1981.

(ii) MF Broadcasting 1605–1705 kHz, Rio de Janeiro, 1988.

(3) Bi-lateral Agreements between the United States and Canada relating to:

(i) AM Broadcasting.

(ii) FM Broadcasting.

(iii) TV Broadcasting.

(4) Bi-lateral Agreements between the United States and Mexico relating to:

(i) AM Broadcasting.

(ii) FM Broadcasting.

(iii) TV Broadcasting.

(5) Bi-lateral Agreement between the United States and the Bahama Islands relating to presunrise operations by AM stations.

(6) North American Regional Broadcasting Agreement (NARBA), which, for the United States, remains in effect with respect to the Dominican Republic and the Bahama Islands.

The documents listed in this paragraph are available for inspection in the office of the Chief, Planning and Negotiations Division, International Bureau, FCC, Washington, DC. Copies may be purchased from the FCC Copy Contractor, whose name may be obtained from the FCC Consumer Assistance Office.

[54 FR 39737, Sept. 28, 1989, as amended at 56 FR 64872, Dec. 12, 1991; 60 FR 5333, Jan. 27, 1995]

(a)(1) An AM, FM, or TV transmitter shall be verified for compliance with the requirements of this part following the procedures described in part 2 of this chapter.

(2) An LPFM transmitter shall be certified for compliance with the requirements of this part following the procedures described in part 2 of the this chapter.

(b) A permittee or licensee planning to modify a transmitter which has been approved by the FCC or verified for compliance must follow the requirements contained in §73.1690.

(c) A transmitter which was in use prior to January 30, 1955, may continue to be used by the licensee, and successors or assignees, if it continues to comply with the technical requirements for the type of station at which it is used.

(d) AM stereophonic exciter-generators for interfacing with approved or verified AM transmitters may be certified upon request from any manufacturer in accordance with the procedures described in part 2 of the FCC rules. Broadcast licensees may modify their certified AM stereophonic exciter-generators in accordance with §73.1690.

(e) Additional rules covering certification and verification, modification of authorized transmitters, and withdrawal of a grant of authorization are contained in part 2 of the FCC rules.

[63 FR 36604, July 7, 1998, as amended at 65 FR 30004, May 10, 2000; 65 FR 67304, Nov. 9, 2000]

(a) Each AM, FM, TV and Class A TV broadcast station must have at least one main transmitter which complies with the provisions of the transmitter technical requirements for the type and class of station. A main transmitter is one which is used for regular program service having power ratings appropriate for the authorized operating power(s).

(b) There is no maximum power rating limit for FM, TV or Class A TV station transmitters, however, the maximum rated transmitter power of a main transmitter stalled at an AM station shall be as follows:

(c) A licensee may, without further authority or notification to the FCC, replace an existing main transmitter or install additional main transmitter(s) for use with the authorized antenna if the replacement or additional transmitter(s) has been verified for compliance. Within 10 days after commencement of regular use of the replacement or additional transmitter(s), equipment performance measurements, as prescribed for the type of station are to be completed.

Note to paragraph (c): Pending the availability of AM broadcast transmitters that are approved or verified for use in the 1605–1705 kHz band, transmitters that are approved or verified for use in the 535–1605 kHz band may be utilized in the 1605–1705 kHz band if it is shown that the requirements of §73.44 have been met. Verification or FCC approval of the transmitter will supersede the applicability of this note.

[43 FR 53741, Nov. 17, 1978, as amended at 47 FR 8590, Mar. 1, 1982; 47 FR 28388, June 30, 1982; 49 FR 4000, Feb. 1, 1984; 51 FR 18451, May 20, 1986; 56 FR 64872, Dec. 12, 1991; 63 FR 36604, July 7, 1998; 65 FR 30004, May 10, 2000]

(a) A licensee of a broadcast station may, without further authority from the FCC, install and use with the main antenna system one or more auxiliary transmitters for the following purposes:

(1) The transmission of regular programs upon failure of the main transmitter.

(2) The transmission of regular programs during maintenance or modification of the main transmitter.

(3) Emergency broadcast system operation.

(4) The transmission of regular programs by an AM station authorized for Presunrise (PSRA) and/or Postsunset (PSSA) operation.

(5) The transmission of tests to determine the operating condition of the auxiliary transmitter or auxiliary antenna.

(6) For testing, upon the request of representatives of the FCC.

(b) Authorization to install an auxiliary transmitter for use with other than the main antenna or authorized auxiliary antenna must be obtained by filing an application for a construction permit on FCC form 301 (FCC form 340 for noncommercial educational stations).

(c) The following technical and operating standards apply to auxiliary transmitters:

(1) The auxiliary transmitter may be operated on only the station's authorized frequency and within the required carrier frequency departure tolerance for the type of station.

(2) The carrier frequency of the auxiliary transmitter must be measured as often as necessary to ensure that it is maintained within the prescribed tolerance.

(3) When using an auxiliary transmitter, the operating power may be less than the authorized power but may not exceed the authorized power within the permitted tolerance for the type of station. If operation with an auxiliary transmitter at reduced power continues for a period exceeding 10 days, the FCC in Washington, DC must be notified. (See §73.51, AM; §73.267, FM; §73.567, NCE-FM; and §73.663, TV).

(4) Normal operator requirements apply to the operation of the auxiliary transmitter.

Note: After January 1, 1979, new licenses will not be issued nor will existing licenses be renewed for auxiliary transmitters that are operated into the main antenna system.

[43 FR 53741, Nov. 17, 1978, as amended at 44 FR 22740, Apr. 17, 1979; 48 FR 36463, Aug. 11, 1983; 48 FR 42960, Sept. 20, 1983; 48 FR 44806, Sept. 30, 1983; 50 FR 32417, Aug. 12, 1985; 51 FR 32088, Sept. 9, 1986]

(a)(1) An auxiliary antenna is one that is permanently installed and available for use when the main antenna is out of service for repairs or replacement. An auxiliary antenna may be located at the same transmitter site as the station's main antenna or at a separate site. The service contour of the auxiliary antenna may not extend beyond the following corresponding contour for the main facility:

(i) AM stations: The 0.5 mV/m field strength contours.

(ii) FM stations: The 1.0 mV/m field strength contours.

(iii) TV stations: The Grade B coverage contours.

(iv) Class A TV stations: The protected contours defined in §73.6010.

(2) An application for an auxiliary antenna for an AM station filed pursuant to paragraphs (b) or (c) of this section must contain a map showing the 0.5 mV/m field strength contours of both the main and auxiliary facilities.

(b) An application for a construction permit to install a new auxiliary antenna, or to make changes in an existing auxiliary antenna for which prior FCC authorization is required (see §73.1690), must be filed on FCC Form 301 (FCC Form 340 for noncommercial educational stations).

(c)(1) Where an FM, TV or Class A TV licensee proposes to use a formerly licensed main facility as an auxiliary facility, or proposes to modify a presently authorized auxiliary facility, and no changes in the height of the antenna radiation center are required in excess of the limits in §73.1690(c)(1), the FM, TV or Class A TV licensee may apply for the proposed auxiliary facility by filing a modification of license application. The modified auxiliary facility must operate on the same channel as the licensed main facility. An exhibit must be provided with this license application to demonstrate compliance with §73.1675(a). All FM, TV and Class A TV licensees may request a decrease from the authorized facility's ERP in the license application. An FM, TV or Class A TV licensee may also increase the ERP of the auxiliary facility in a license modification application, provided the application contains an analysis demonstrating compliance with the Commission's radiofrequency radiation guidelines, and an analysis showing that the auxiliary facility will comply with §73.1675(a). Auxiliary facilities mounted on an AM antenna tower must also demonstrate compliance with §73.1692 in the license application.

(2) Where an AM licensee proposes to use a former licensed main facility as an auxiliary facility with an ERP less than or equal to the ERP specified on the former main license, the AM station may apply to license the proposed auxiliary facility by filing a modification of license application on Form 302-AM. The proposed auxiliary facilities must have been previously licensed on the same frequency as the present main facility. The license application must contain an exhibit to demonstrate compliance with §73.1675(a).

[43 FR 53741, Nov. 17, 1978, as amended at 44 FR 22740, Apr. 17, 1979; 45 FR 26066, Apr. 17, 1980; 50 FR 13974, Apr. 9, 1985; 62 FR 51060, Sept. 30, 1997; 63 FR 70049, Dec. 18, 1998; 65 FR 30005, May 10, 2000]

(a) An emergency antenna is one that is erected for temporary use after the authorized main and auxiliary antennas are damaged and cannot be used.

(b) Prior authority from the FCC is not required by licensees and permittees to erect and commence operations using an emergency antenna to restore program service to the public. However, an informal letter request to continue operation with the emergency antenna must be made within 24 hours to the FCC in Washington, DC, Attention: Audio Division (radio) or Video Division (television), Media Bureau, within 24 hours after commencement of its use. The request is to include a description of the damage to the authorized antenna, a description of the emergency antenna, and the station operating power with the emergency antenna.

(1) AM stations. AM stations may use a horizontal or vertical wire or a nondirectional vertical element of a directional antenna as an emergency antenna. AM stations using an emergency nondirectional antenna or a horizontal or vertical wire pursuant to this section, in lieu or authorized directional facilities, shall operate with power reduced to 25% or less of the nominal licensed power, or, a higher power, not exceeding licensed power, while insuring that the radiated filed strength does not exceed that authorized in any given azimuth for the corresponding hours of directional operation.

(2) FM, TV and Class A TV stations. FM, TV and Class A TV stations may erect any suitable radiator, or use operable sections of the authorized antenna(s) as an emergency antenna.

(c) The FCC may prescribe the output power, radiation limits, or other operating conditions when using an emergency antenna, and emergency antenna authorizations may be modified or terminated in the event harmful interference is caused to other stations or services by the use of an emergency antenna.

[43 FR 53741, Nov. 17, 1978, as amended at 44 FR 22740, Apr. 17, 1979; 50 FR 30948, July 31, 1985; 63 FR 33878, June 22, 1998; 65 FR 30005, May 10, 2000; 67 FR 13232, Mar. 21, 2002]

The following procedures and restrictions apply to licensee modifications of authorized broadcast transmission system facilities.

(a) The following changes are prohibited:

(1) Those that would result in the emission of signals outside of the authorized channel exceeding limits prescribed for the class of service.

(2) Those that would cause the transmission system to exceed the equipment performance measurements prescribed for the class of service (AM, §73.44; FM, §§73.317, 73.319, and 73.322; TV and Class A TV, §§73.682 and 73.687).

(b) The following changes may be made only after the grant of a construction permit application on FCC Form 301 for commercial stations or Form 340 for noncommercial educational stations:

(1) Any construction of a new tower structure for broadcast purposes, except for replacement of an existing tower with a new tower of identical height and geographic coordinates.

(2) Any change in station geographic coordinates, including coordinate corrections of more than 3 seconds latitude and/or 3 seconds longitude. FM and TV directional stations must also file a construction permit application for any move of the antenna to another tower structure located at the same coordinates.

(3) Any change which would require an increase along any azimuth in the composite directional antenna pattern of an FM station from the composite directional antenna pattern authorized (see §73.316), or any increase from the authorized directional antenna pattern for a TV broadcast (see §73.685) or Class A TV station (see §73.6025).

(4) Any change in the directional radiation characteristics of an AM directional antenna system. See §73.45 and §73.150.

(5) Any decrease in the authorized power of an AM station or the ERP of a TV or Class A TV station, or any decrease or increase in the ERP of an FM commercial station, which is intended for compliance with the multiple ownership rules in §73.3555.

(6) For FM noncommercial educational stations, any of the following:

(i) Any increase in the authorized maximum ERP, whether horizontally or vertically polarized, for a noncommercial educational FM station operating on Channels 201 through 220, or a Class D FM station operating on Channel 200.

(ii) For those FM noncommercial educational stations on Channels 201 to 220, or a Class D FM station operating on Channel 200, which are within the separation distances specified in Table A of §73.525 with respect to a Channel 6 television station, any increase in the horizontally or vertically polarized ERP from the presently authorized ERP.

(iii) For those FM noncommercial educational stations on Channels 201 through 220 which are located within the separation distances in §73.525 with respect to a Channel 6 television station, or a Class D FM station operating on Channel 200, any decrease in the presently authorized horizontal effective radiated power which would eliminate the horizontal ERP to result in use of vertical ERP only.

(iv) For those FM noncommercial educational stations which employ separate antennas for the horizontal ERP and the vertical ERP, mounted at different heights, the station may not increase or decrease either the horizontal ERP or the vertical ERP without a construction permit.

(7) Any increase in the authorized ERP of a television station, Class A television station, FM commercial station, or noncommercial educational FM station, except as provided for in §§73.1690(c)(4), (c)(5), or (c)(7), or in §73.1675(c)(1) in the case of auxiliary facilities.

(8) A commercial TV or noncommercial educational TV station operating on Channels 14 or Channel 69 or a Class A TV station on Channel 14 may increase its horizontally or vertically polarized ERP only after the grant of a construction permit. A television or Class A television station on Channels 15 through 21 within 341 km of a cochannel land mobile operation, or 225 km of a first-adjacent channel land mobile operation, must also obtain a construction permit before increasing the horizontally or vertically polarized ERP (see part 74, §74.709(a) and (b) for tables of urban areas and corresponding reference coordinates of potentially affected land mobile operations).

(c) The following FM, TV and Class A TV station modifications may be made without prior authorization from the Commission. A modification of license application must be submitted to the Commission within 10 days of commencing program test operations pursuant to §73.1620. With the exception of applications filed solely pursuant to paragraphs (c)(6), (c)(9), or (c)(10) of this section, the modification of license application must contain an exhibit demonstrating compliance with the Commission's radio frequency radiation guidelines. In addition, except for applications solely filed pursuant to paragraphs (c)(6) or (c)(9) of this section, where the installation is located within 3.2 km of an AM tower or is located on an AM tower, an exhibit demonstrating compliance with §73.1692 is also required.

(1) Replacement of an omnidirectional antenna with one of the same or different number of antenna bays, provided that the height of the antenna radiation center is not more than 2 meters above or 4 meters below the authorized values. Any concurrent change in ERP must comply with §73.1675(c)(1), 73.1690(4), (c)(5), or (c)(7). Program test operations at the full authorized ERP may commence immediately upon installation pursuant to §73.1620(a)(1).

(2) Replacement of a directional FM antenna, where the measured composite directional antenna pattern does not exceed the licensed composite directional pattern at any azimuth, where no change in effective radiated power will result, and where compliance with the principal coverage requirements of §73.315(a) will be maintained by the measured directional pattern. The antenna must be mounted not more than 2 meters above or 4 meters below the authorized values. The modification of license application on Form 302-FM to cover the antenna replacement must contain all of the data in the following sections (i) through (v). Program test operations at one half (50%) power may commence immediately upon installation pursuant to §73.1620(a)(3). However, if the replacement directional antenna is an exact replacement (i.e., no change in manufacturer, antenna model number, AND measured composite antenna pattern), program test operations may commence immediately upon installation at the full authorized power.

(i) A measured directional antenna pattern and tabulation on the antenna manufacturer's letterhead showing both the horizontally and vertically polarized radiation components and demonstrating that neither of the components exceeds the authorized composite antenna pattern along any azimuth.

(ii) Contour protection stations authorized pursuant to §73.215 or §73.509 must attach a showing that the RMS (root mean square) of the composite measured directional antenna pattern is 85% or more of the RMS of the authorized composite antenna pattern. See §73.316(c)(9). If this requirement cannot be met, the licensee may include new relative field values with the license application to reduce the authorized composite antenna pattern so as to bring the measured composite antenna pattern into compliance with the 85 percent requirement.

(iii) A description from the manufacturer as to the procedures used to measure the directional antenna pattern. The antenna measurements must be performed with the antenna mounted on a tower, tower section, or scale model equivalent to that on which the antenna will be permanently mounted, and the tower or tower section must include transmission lines, ladders, conduits, other antennas, and any other installations which may affect the measured directional pattern.

(iv) A certification from a licensed surveyor that the antenna has been oriented to the proper azimuth.

(v) A certification from a qualified engineer who oversaw installation of the directional antenna that the antenna was installed pursuant to the manufacturer's instructions.

(3) A directional TV on Channels 2 through 13 or 22 through 68 or a directional Class A TV on Channels 2 through 13 or 22 through 51, or a directional TV or Class A TV station on Channels 15 through 21 which is in excess of 341 km (212 miles) from a cochannel land mobile operation or in excess of 225 km (140 miles) from a first-adjacent channel land mobile operation (see part 74, §74.709(a) and (b) for tables of urban areas and reference coordinates of potentially affected land mobile operations), may replace a directional TV or Class A TV antenna by a license modification application, if the proposed horizontal theoretical directional antenna pattern does not exceed the licensed horizontal directional antenna pattern at any azimuth and where no change in effective radiated power will result. The modification of license application on Form 302–TV or Form 302–CA must contain all of the data set forth in §73.685(f) or §73.6025(a), as applicable.

(4) Commercial and noncommercial educational FM stations operating on Channels 221 through 300 (except Class D), NTSC TV stations operating on Channels 2 through 13 and 22 through 68, Class A TV stations operating on Channels 2 through 13 and 22 through 51, and TV and Class A TV stations operating on Channels 15 through 21 that are in excess of 341 km (212 miles) from a cochannel land mobile operation or in excess of 225 km (140 miles) from a first-adjacent channel land mobile operation (see part 74, §74.709(a) and (b) for tables of urban areas and reference coordinates of potentially affected land mobile operations), which operate omnidirectionally, may increase the vertically polarized effective radiated power up to the authorized horizontally polarized effective radiated power in a license modification application. Noncommercial educational FM licensees and permittees on Channels 201 through 220, that do not use separate antennas mounted at different heights for the horizontally polarized ERP and the vertically polarized ERP, and are located in excess of the separations from a Channel 6 television station listed in Table A of §73.525(a)(1), may also increase the vertical ERP, up to (but not exceeding) the authorized horizontally polarized ERP via a license modification application. Program test operations may commence at full power pursuant to §73.1620(a)(1).

(5) Those Class A FM commercial stations which were permitted to increase ERP pursuant to MM Docket No. 88–375 by a modification of license application remain eligible to do so, provided that the station meets the requirements of §73.1690 (c)(1) and is listed on one of the Public Notices as authorized to increase ERP, or by a letter from the Commission's staff authorizing the change. These Public Notices were released on November 3, 1989; November 17, 1989; December 8, 1989; March 2, 1990; and February 11, 1991. The increased ERP must comply with the multiple ownership requirements of §73.3555. Program test operations may commence at full power pursuant to §73.1620(a)(1).

(6) FM contour protection stations authorized pursuant to §73.215 which have become fully spaced under §73.207 may file a modification of license application to delete the §73.215 contour protection designation with an exhibit to demonstrate that the station is fully spaced in accordance with §73.207. The contour protection designation will be removed upon grant of the license application. Applications filed under this rule section will be processed on a first come / first served basis with respect to conflicting FM commercial minor change applications and modification of license applications (including those filed pursuant to §73.1690 (b) and (c)(6) and (c)(7)).

(7) FM omnidirectional commercial stations, and omnidirectional noncommercial educational FM stations operating on Channels 221 through 300 (except Class D), which are not designated as contour protection stations pursuant to §73.215 and which meet the spacing requirements of §73.207, may file a license modification application to increase ERP to the maximum permitted for the station class, provided that any change in the height of the antenna radiation center remains in accordance with §73.1690(c)(1). Program test operations may commence at full power pursuant to §73.1620(a)(1). All of the following conditions also must be met before a station may apply pursuant to this section:

(i) The station may not be a “grandfathered” short-spaced station authorized pursuant to §73.213 or short-spaced by a granted waiver of §73.207;

(ii) If the station is located in or near a radio quiet zone, radio coordination zone, or a Commission monitoring station (see §73.1030 and §0.121(c)), the licensee or permittee must have secured written concurrence from the affected radio quiet zone, radio coordination zone, or the Commission's Compliance and Information Bureau in the case of a monitoring station, to increase effective radiated power PRIOR to implementation. A copy of that concurrence must be submitted with the license application to document that concurrence has been received;

(iii) The station does not require international coordination as the station does not lie within the border zones, or clearance has been obtained from Canada or Mexico for the higher power operation within the station's specified domestic class and the station complies with §73.207(b)(2) and (3) with respect to foreign allotments and allocations;

(iv) The increased ERP will not cause the station to violate the multiple ownership requirements of §73.3555.

(8) FM commercial stations and FM noncommercial educational stations may decrease ERP on a modification of license application provided that exhibits are included to demonstrate that all six of the following requirements are met:

(i) Commercial FM stations must continue to provide a 70 dBu principal community contour over the community of license, as required by §73.315(a). Noncommercial educational FM stations must continue to provide a 60 dBu contour over at least a portion of the community of license. The 60 and 70 dBu contours must be predicted by use of the standard contour prediction method in §73.313(b), (c), and (d).

(ii) For both commercial FM and noncommercial educational FM stations, the location of the main studio remains within the 70 dBu principal community contour, as required by §73.1125, or otherwise complies with that rule. The 70 dBu contour must be predicted by use of the standard contour prediction method in §73.313(b), (c), and (d).

(iii) For commercial FM stations only, there is no change in the authorized station class as defined in §73.211.

(iv) For commercial FM stations only, the power decrease is not necessary to achieve compliance with the multiple ownership rule, §73.3555.

(v) Commercial FM stations, noncommercial educational FM stations on Channels 221 through 300, and noncommercial educational FM stations on Channels 200 through 220 which are located in excess of the distances in Table A of §73.525 with respect to a Channel 6 TV station, may not use this rule to decrease the horizontally polarized ERP below the value of the vertically polarized ERP.

(vi) Noncommercial educational FM stations on Channels 201 through 220 which are within the Table A distance separations of §73.525, or Class D stations on Channel 200, may not use the license modification process to eliminate an authorized horizontally polarized component in favor of vertically polarized-only operation. In addition, noncommercial educational stations operating on Channels 201 through 220, or Class D stations on Channel 200, which employ separate horizontally and vertically polarized antennas mounted at different heights, may not use the license modification process to increase or decrease either the horizontal ERP or vertical ERP without a construction permit.

(9) The licensee of an AM, FM, or TV commercial station may propose to change from commercial to noncommercial educational on a modification of license application, provided that the application contains completed Sections II and IV of FCC Form 340. In addition, a noncommercial educational AM licensee, a TV licensee on a channel not reserved for noncommercial educational use, or an FM licensee on Channels 221 to 300 (except Class D FM) on a channel not reserved for noncommercial educational use, may apply to change from educational to commercial via a modification of license application, and no exhibits are required with the application. The change will become effective upon grant of the license application.

(10) Replacement of a transmission line with one of a different type or length which changes the transmitter operating power (TPO) from the authorized value, but not the ERP, must be reported in a license modification application to the Commission.

(11) Correction of geographic coordinates where the change is 3 seconds or fewer in latitude and/or 3 seconds or fewer in longitude, provided there is no physical change in location and no other licensed parameters are changed. The correction of coordinates may not result in any new short spacings or increases in existing short spacings.

(d) The following changes may be made without authorization from the FCC, however informal notification of the changes must be made according to the rule sections specified:

(1) Change in studio location within the principal community contour. See §73.1125.

(2) Commencement of remote control operation pursuant to §§73.1400 and 73.1410.

(3) Modification of an AM directional antenna sampling system. See §73.68.

(e) Any electrical and mechanical modification to authorized transmitting equipment that is not otherwise restricted by the preceding provisions of this section, may be made without FCC notification or authorization. Equipment performance measurements must be made within ten days after completing the modifications (See §73.1590). An informal statement, diagram, etc., describing the modification must be retained at the transmitter site for as long as the equipment is in use.

[47 FR 8590, Mar. 1, 1982]

Editorial Note:  For Federal Register citations affecting §73.1690, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO Access.

§ 73.1692   Broadcast station construction near or installation on an AM broadcast tower.

Where a broadcast licensee or permittee proposes to mount a broadcast antenna on an AM station tower, or where construction is proposed within 0.8 km of an AM nondirectional tower or within 3.2 km of an AM directional station, the broadcast licensee or permittee is responsible for ensuring that the construction does not adversely affect the AM station, as follows:

(a) Installations on an AM nondirectional tower. During installation of the broadcast antenna and related equipment, the AM station shall determine operating power by the indirect method (see §73.51). Upon the completion of the installation, antenna impedance measurements on the AM antenna shall be made, and, prior to or simultaneously with the filing of the license application covering the broadcast station installation, an application on FCC Form 302–AM (including a tower sketch of the installation) shall be filed with the Commission for the AM station to return to direct power measurement.

(b) Installations on an AM directional array. Prior to commencing construction, the broadcast permittee or licensee shall notify the AM station so that, if necessary, the AM station may determine operating power by the indirect method (see §73.51) and request special temporary authority pursuant to §73.1635 to operate with parameters at variance in order to maintain monitoring point field strengths within authorized limits. Both prior to the commencement of construction and upon completion of construction, a partial proof of performance (as defined by §73.154) shall be conducted to establish that the AM array has not been adversely affected. Prior to or simultaneously with filing of the license application to cover the broadcast station construction, the results of the partial proof of performance shall be filed with the Commission on Form 302–AM.