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]