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 Code of Federal Regulations (Last Updated: October 10, 2024)
 Title 47 - Telecommunication
 Chapter I - Federal Communications Commission
 SubChapter C - Broadcast Radio Services
 Part 74 - Experimental Radio, Auxiliary, Special Broadcast and Other Program Distributional Services
 Subpart E - Aural Broadcast Auxiliary Stations

  § 74.536 - Directional antenna required.  

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  • § 74.536 Directional antenna required.

    (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.

    Antenna Standards

    Frequency (GHz) Category Maximum beamwidth to 3 dB points1
    (included angle in
    degrees)     		Minimum antenna gain (dbi) Minimum radiation suppression to angle in degrees from centerline of main beam in decibels
    5° to 10° 10° to 15° 15° to 20° 20° to 30° 30° to 100° 100° to 140° 140° to 180°
    17.7 to 19.7 A
    B    		 2.2
    2.2    		 38
    38    		 25
    20    		 29
    24    		 33
    28    		 36
    32    		 42
    35    		 55
    36    		 55
    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.

    [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]