Sec. 90.307  Protection criteria.

    The tables and figures listed in Sec. 90.309 shall be used to 
determine the proper power (ERP) and antenna height of the proposed land 
mobile base station and the proper power (ERP) for the associated 
control station (control station antenna height shall not exceed 31 m. 
(100 ft.) above average terrain (AAT)).
    (a) Base stations operating on the frequencies available for land 
mobile use in any listed urbanized area and having an antenna height 
(AAT) less than 152 m. (500 ft.) shall afford protection to co-channel 
and adjacent channel television stations in accordance with the values 
set out in tables A and E of this subpart, except for Channel 15 in New 
York, NY, and Cleveland, OH, and Channel 16 in Detroit, MI, where 
protection will be in accordance with the values set forth in tables B 
and E.
    (b) For base stations having antenna heights between 152-914 meters 
(500-3,000 ft.) above average terrain, the effective radiated power must 
be reduced below 1 kilowatt in accordance with the values shown in the 
power reduction graph in Figure A, except for Channel 15 in New York, 
NY, and Cleveland, OH, and Channel 16 in Detroit, MI, where the 
effective radiated power must be reduced in accordance with Figure B. 
For heights of more than 152 m. (500 ft.) above average terrain, the 
distance to the radio path horizon will be calculated assuming smooth 
earth. If the distance so determined equals or exceeds the distance to 
the Grade B contour of a co-channel TV station, (Grade B contour defined 
in Sec. 73.683(a)) an authorization will not be granted unless it can be 
shown that actual terrain considerations are such as to provide the 
desired protection at the Grade B contour, or that the effective 
radiated power will be further reduced so that, assuming free space 
attenuation, the desired protection at the Grade B contour will be 
achieved.
    (c) Mobile units and control stations operating on the frequencies 
available for land mobile use in any given urbanized area shall afford 
protection to co-channel and adjacent channel television stations in 
accordance with the values set forth in table C and paragraph (d) of 
this section except for Channel 15 in New York, NY, and Cleveland, OH, 
and Channel 16 in Detroit, MI, where protection will be in accordance 
with the values set forth in table D and paragraph (d) of this section.
    (d) The minimum distance between a land mobile base station which 
has associated mobile units and a protected adjacent channel television 
station is 145 km (90 miles) .
    (e) The television stations to be protected (co-channel, adjacent 
channel, IM, and IF) in any given urbanized area, in accordance with the 
provisions of paragraphs (a), (b), (c), and (d) of this section, are 
identified in the commission's publication ``TV stations to be 
considered in the preparation of Applications for Land Mobile Facilities 
in the Band 470-512 MHz.'' The publication is available at the offices 
of the Federal Communications Commission at Washington, DC or upon the 
request of interested persons.
[ 43 FR 54791 , Nov. 22, 1978, as amended at  49 FR 36107 , Sept. 14, 1984; 
 58 FR 44957 , Aug. 25, 1993]