§  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 points^1
   (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

   ^1If 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]