View all text of Subpart K [§ 90.251 - § 90.283]
§ 90.261 - Assignment and use of the frequencies in the band 450-470 MHz for fixed operations.
(a) Frequencies in the 450-470 MHz band as listed in §§ 90.20(c)(3) and 90.35(b)(3) may be assigned to all eligibles for fixed use on a secondary basis to land mobile operations.
(b) Fixed stations located 140 km (87 mi) or more from the center of any urbanized area of 600,000 or more population are limited to a transmitter output power of 75 watts. Fixed stations less than 140 km (87 mi) from the centers of these areas are limited to a transmitter output power of 20 watts. Urbanized areas of 600,000 or more population are defined in the U.S. Census of Population 1970, Vol. 1, Table 20, pages 1-74. The centers of the urbanized areas are determined from the Appendix, page 226, of the U.S. Department of Commerce publication “Airline Distance Between Cities in the United States.”
(c) All fixed systems are limited to one frequency pair with 5 MHz spacing and must employ directional antennas with a front-to-back ratio of 15dB, except that omnidirectional antennas having unity gain may be employed by stations communicating with a minimum of three receiving locations encompassed in a sector of at least 160° in azimuth. Stations authorized for secondary fixed operations prior to July 13, 1992, may continue to operate under the conditions of their initial authorization.
(d)-(e) [Reserved]
(f) Secondary fixed operations pursuant to paragraph (a) of this section will not be authorized on the following frequencies or on frequencies subject to § 90.267, except as provided in § 90.219(d)(3)(ii):
Frequencies (MHz) 451.800/456.800 451.80625/456.80625 451.8125/456.8125 451.81875/456.81875 452.525 452.53125 452.5375 452.54375 452.550 452.55625 452.5625 452.56875 452.575 452.58125 452.5875 452.59375 452.600 452.60625 452.6125 452.61875 452.925/457.925 452.93125/457.93125 452.9375/457.9375 452.94375/457.94375 452.950/457.950 452.95625/457.95625 452.9625/457.9625 452.96875/457.96875 453.025/458.025 453.03125/458.03125 453.0375/458.0375 453.04375/458.04375 453.075/458.075 453.08125/458.08125 453.0875/458.0875 453.09375/458.09375 453.125/458.125 453.13125/458.13125 453.1375/458.1375 453.14375/458.14375 453.175/458.175 453.18125/458.18125 453.1875/458.1875 453.19375/458.19375 454.000/459.000 454.00625/459.00625 454.0125/459.0125 454.01875/459.01875 462.950/467.950 462.95625/467.95625 462.9625/467.9625 462.96875/467.96875 462.975/467.975 462.98125/467.98125 462.9875/467.9875 462.99375/467.99375 463.000/468.000 463.00625/468.00625 463.0125/468.0125 463.01875/468.01875 463.025/468.025 463.03125/468.03125 463.0375/468.0375 463.04375/468.04375 463.050/468.050 463.05625/468.05625 463.0625/468.0625 463.06875/468.06875 463.075/468.075 463.08125/468.08125 463.0875/468.0875 463.09375/468.09375 463.100/468.100 463.10625/468.10625 463.1125/468.1125 463.11875/468.11875 463.125/468.125 463.13125/468.13125 463.1375/468.1375 463.14375/468.14375 463.150/468.150 463.15625/468.15625 463.1625/468.1625 463.16875/468.16875 463.175/468.175 463.18125/468.18125 463.1875/468.1875 463.19375/468.19375