Sec.  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 Sta
ndards
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                                                                   Maximum
              Minimum radiation suppression to angle in degrees from
                                                                  beamwidth
                        centerline of main beam in decibels
                                                                   to 3 dB    M
inimum  -----------------------------------------------------------------
                   Frequency (GHz)                      Category   points 1   a
ntenna
                                                                  (included
 gain     5 °  10 °  15 °  20 °   30 °  100 °  140 °
                                                                   angle in
(dbi)       to       to       to       to       to        to        to
                                                                   degrees)
         10 °  15 °  20 °  30 °  100 °  140 °  180 °
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
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
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\1\ If a licensee chooses to show compliance using maximum beamwidth to 3 dB po
ints, 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]