47 C.F.R. § 74.536 Directional antenna required.
Title 47 - Telecommunication
(a) Aural broadcast STL and ICR stations are required to use a directional antenna with the minimum beamwidth necessary, consistent with good engineering practice, to establish the link. (b) An aural broadcast STL or intercity relay station operating in the 17.7–19.7 GHz band shall employ an antenna that meets the performance standards for Category A, except that in areas not subject to frequency congestion, antennas meeting standards for Category B may be employed. However, the Commission may require the replacement, at the licensee's expense, of any antenna or periscope antenna system of a permanent fixed station that does not meet performance Standard A, which is specified in the table in paragraph (c) of this section, upon a showing that said antenna causes or is likely to cause interference to (or receive interference from) any other authorized or proposed station; provided that an antenna meeting performance Standard A is unlikely to involve such interference. (c) Licensees shall comply with the antenna standards table shown in this paragraph in the following manner: (1) With either the maximum beamwidth to 3 dB points requirement or with the minimum antenna gain requirement; and (2) With the minimum radiation suppression to angle requirement. [48 FR 50333, Nov. 1, 1983, as amended at 49 FR 7130, Feb. 27, 1984; 50 FR 48599, Nov. 26, 1985; 51 FR 19840, June 3, 1986; 62 FR 4922, Feb. 3, 1997; 68 FR 12767, Mar. 17, 2003]
Title 47: Telecommunication
PART 74—EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES
Subpart E—Aural Broadcast Auxiliary Stations
§ 74.536 Directional antenna required.
Antenna Standards-------------------------------------------------------------------------------------------------------------------------------------------------------- Maximum Minimum radiation suppression to angle in degrees from beamwidth centerline of main beam in decibels to 3 dB Minimum ----------------------------------------------------------------- points antenna Frequency (GHz) Category \1\ gain 5° 10° 15° 20° 30° 100° 140° (included (dbi) to to to to to to to angle in 10° 15° 20° 30° 100° 140° 180° degrees)--------------------------------------------------------------------------------------------------------------------------------------------------------17.7 to 19.7......................................... A 2.2 38 25 29 33 36 42 55 55 B 2.2 38 20 24 28 32 35 36 36--------------------------------------------------------------------------------------------------------------------------------------------------------\1\ If a licensee chooses to show compliance using maximum beamwidth to 3 dB points, the beamwidth limit shall apply in both the azimuth and the elevation planes.
