§ 22.657   Transmitter locations.

   The purpose of the rules in paragraphs (a) and (b) of this section is to
   define the areas in which the 470-512 MHz channels are allocated for public
   mobile use. The purpose of the rules in paragraphs (c) through (f) of this
   section  is  to  reduce the likelihood that interference to television
   reception from public mobile operations on these channels will occur. The
   protected TV station locations specified in paragraphs (d), (e)(1) and (f)
   of this section are the locations of record as of September 1974, and these
   do  not  change even though the TV stations may have been subsequently
   relocated.

   (a) Base transmitter locations. Base transmitter locations must be within 80
   kilometers (50 miles) of the designated locations in this paragraph. Mobile
   transmitters must not be operated at locations more than 129 kilometers (80
   miles)  from  the  designated  locations  in this paragraph. Note: All
   coordinates are referenced to North American Datum 1983 (NAD83).
       Urban area     N. latitude W. longitude
   Houston, TX        29°45′26.8″  95°21′37.8″
   New York, NY-NE NJ 40°45′06.4″  73°59′37.5″

   (b) Mobile area of operation. Mobile transmitters must not be operated at
   locations  more than 48 kilometers (30 miles) from all associated base
   stations.

   (c) Protection from intermodulation interference. Base transmitter locations
   must be at least 1.6 kilometers (1 mile) from the current main transmitter
   locations of all TV stations transmitting on TV channels separated by 2, 3,
   4, 5, 7, or 8 TV channels from the TV channel containing the frequencies on
   which the base station will transmit. This requirement is intended to reduce
   the likelihood of intermodulation interference.

   (d) Adjacent channel protection from mobile transmitters. Base transmitter
   locations must be at least 145 kilometers (90 miles) from the applicable
   protected TV station locations specified in this paragraph. This requirement
   is intended to provide a 0 dB minimum desired to undesired signal strength
   ratio at the Grade B contour of an adjacent channel TV station. Note: All
   coordinates are referenced to North American Datum 1983 (NAD83).
   Control transmitter frequency range Protected TV station location TV channel
   470-476 MHz Lancaster, PA, 40°15′45.3″ N. Lat. 76°27′47.9″ W. Long. (15)
   476-482 MHz Scranton, PA, 41°10′58.3″ N. Lat. 75°52′19.7″ W. Long. (16)

   (e)  Co-channel  protection from mobile transmitters. Base transmitter
   locations must be at least the distance specified in paragraph (e)(2) of
   this section from the applicable protected TV station locations specified in
   paragraph (e)(1) of this section. This requirement is intended to provide a
   40 dB minimum desired to undesired signal strength ratio at the Grade B
   contour of a co-channel TV station.

   (1) The protected TV station locations are as follows (all coordinates are
   referenced to North American Datum 1983 (NAD83)):
   Control transmitter frequency range Protected TV station location
   470-476 MHz Washington, DC, 38°57′17.4″ N. Lat. 77°00′15.9″ W. Long.
   476-482 MHz Lancaster, PA, 40°15′45.3″ N. Lat. 76°27′47.9″ W. Long.

   (2) The required minimum distance depends upon the effective radiated power
   (ERP) of the most powerful mobile transmitter(s) in the system:
   Mobile unit ERP (watts) Minimum distance
                           Kilometers Miles
   60                              193 (120)
   50                              185 (115)
   25                              177 (110)
   10                              169 (105)
   5                               161 (100)

   (f) Co-channel protection from base transmitters with high antennas. This
   paragraph  applies  only  to  base  transmitter  locations  in the New
   York-Northeastern New Jersey urban area that utilize an antenna height of
   more than 152 meters (500 feet) above average terrain. The distance between
   the location of such a base transmitter and the applicable protected TV
   station location specified in this paragraph must equal or exceed the sum of
   the distance from the base transmitter location to the radio horizon in the
   direction of the specified location and 89 kilometers (55 miles—representing
   the distance from the main transmitter location of the TV station to its
   Grade B contour in the direction of the base transmitter). The distance to
   the radio horizon is calculated as follows:
   eCFR graphic er14de98.026.gif

   View or download PDF

   Where d is the distance to the radio horizon in kilometers h is the height
   of the antenna center of radiation above ground level in meters

   Note: All coordinates are referenced to North American Datum 1983 (NAD83)):
   Control transmitter frequency range Protected TV station location
   470-476 MHz Washington, DC, 38°57′17.4″ N. Lat. 77°00′15.9″ W. Long.
   476-482 MHz Lancaster, PA, 40°15′45.3″ N. Lat. 76°27′47.9″ W. Long.

   (g)  The  FCC  may  waive specific distance separation requirements of
   paragraphs (d) through (f) of this section if the applicant submits an
   engineering  analysis  which  demonstrates that terrain effects and/or
   operation with less effective radiated power would satisfy the applicable
   minimum desired to undesired signal strength ratios at the Grade B contours
   of the protected TV stations. For this purpose, the Grade B contour of a TV
   station is deemed to be a circle with a 89 kilometer (55 mile) radius,
   centered on the protected TV station location, and along which the median TV
   signal field strength is 64 dBµV/m. In any showing intended to demonstrate
   compliance with the minimum desired to undesired signal ratio requirements
   of this section, all predicted field strengths must have been determined
   using the UHF TV propagation curves contained in part 73 of this chapter.

   [ 59 FR 59507 , Nov. 17, 1994, as amended at  63 FR 68947 , Dec. 14, 1998]

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