Section 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.(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
57 FR 24992, June 12, 1992, as amended at 58 FR 33212, June 16, 1993; 60 FR 37268, July 19, 1995; 62 FR 18928, Apr. 17, 1997; 68 FR 19461, Apr. 21, 2003; 72 FR 35196, June 27, 2007; 83 FR 61097, Nov. 27, 2018