§  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]