(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--------------------------------------------------------------------------------------------------------------------------------------------------------
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[deg] 10[deg] 15[deg] 20[deg] 30[deg] 100[deg] 140[deg]
(included (dbi) to to to to to to to
angle in 10[deg] 15[deg] 20[deg] 30[deg] 100[deg] 140[deg] 180[deg]
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. [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]