§ 22.625   Transmitter locations.

   This section governs where point-to-multipoint transmitters on the channels
   listed in § 22.621 may be located.

   (a) 928-960 MHz. In this frequency range, the required minimum distance
   separation between co-channel fixed transmitters is 113 kilometers (70
   miles).

   (b) 470-512 MHz. The purpose of the rule in paragraph (b)(1) 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 (b)(2) and (b)(3)
   of this section is to reduce the likelihood that interference to television
   reception from public mobile operations on these channels will occur.

   (1) Control transmitter locations. Control transmitter locations must be
   within  80  kilometers  (50 miles) of the designated locations in this
   paragraph.
          Urban area         N. latitude W. longitude
   Boston, MA                42°21′24.4″  71°03′22.2″
   Chicago, IL               41°52′28.1″  87°38′22.2″
   Cleveland, OH             41°29′51.2″  81°41′49.5″
   Dallas, TX                32°47′09.5″  96°47′38.0″
   Detroit, MI               42°19′48.1″  83°02′56.7″
   Houston, TX               29°45′26.8″  95°21′37.8″
   Los Angeles, CA           34°03′15.0″  18°14′31.3″
   Miami, FL                 25°46′38.6″  80°11′31.2″
   New York, NY               40°45′6.4″  73°59′37.5″
   Philadelphia, PA          39°56′58.4″  75°09′19.6″
   Pittsburgh, PA            40°26′19.2″  79°59′59.2″
   San Francisco-Oakland, CA 37°46′38.7″ 122°24′43.9″
   Washington, DC            38°53′51.4″  77°00′31.9″

   Note: Coordinates are referenced to North American Datum 1983 (NAD 83).

   (2)  Protection from intermodulation interference. Control transmitter
   locations must be at least 1.6 kilometers (1 mile) from the 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 control station will transmit. This requirement is intended to
   reduce the likelihood of intermodulation interference.

   (3) Co-channel protection from control transmitters with high antennas. This
   paragraph applies only to control transmitters that utilize an antenna
   height  of  more than 152 meters (500 feet) above average terrain. The
   distance  between  the  location of such a control transmitter and the
   applicable protected TV station location specified in this paragraph must
   equal  or  exceed the sum of the distance from the control 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
   control transmitter). The protected TV station locations in this paragraph
   are the locations of record as of September 1974, and these do not change
   even though the TV stations may have been subsequently relocated.

   (i) The protected TV station locations are as follows:
   Control transmitter frequency range   Protected TV station location
   470-476 MHz                         Washington, DC 38°57′17″ 77°00′17″
   476-482 MHz                         Lancaster, PA 40°15′45″ 76°27′49″

   (ii) The distance to the radio horizon is calculated using the following
   formula:
   eCFR graphic er17no94.008.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

   [ 59 FR 59507 , Nov. 17, 1994, as amended at  63 FR 68946 , Dec. 14, 1998,  70 FR 19309 , Apr. 13, 2005]

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