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
Frequency (GHz) | Category | Maximum beamwidth to 3 dB points 1(included angle indegrees) | 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 | AB | 2.22.2 | 3838 | 2520 | 2924 | 3328 | 3632 | 4235 | 5536 | 5536 |
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]