§  27.64   Protection from interference.

   Wireless Communications Service (WCS) stations operating in full
   accordance with applicable FCC rules and the terms and conditions of
   their authorizations are normally considered to be non-interfering. If
   the FCC determines, however, that interference which significantly
   interrupts or degrades a radio service is being caused, it may, after
   notice and an opportunity for a hearing, require modifications to any
   WCS station as necessary to eliminate such interference.

   (a) Failure to operate as authorized. Any licensee causing interference
   to the service of other stations by failing to operate its station in
   full accordance with its authorization and applicable FCC rules shall
   discontinue all transmissions, except those necessary for the immediate
   safety of life or property, until it can bring its station into full
   compliance with the authorization and rules.

   (b) Intermodulation interference. Licensees should attempt to resolve
   such interference by technical means.

   (c) Situations in which no protection is afforded. Except as provided
   elsewhere in this part, no protection from interference is afforded in
   the following situations:

   (1) Interference to base receivers from base or fixed transmitters.
   Licensees should attempt to resolve such interference by technical
   means or operating arrangements.

   (2) Interference to mobile receivers from mobile transmitters. No
   protection is provided against mobile-to-mobile interference.

   (3) Interference to base receivers from mobile transmitters. No
   protection is provided against mobile-to-base interference.

   (4) Interference to fixed stations. Licensees should attempt to resolve
   such interference by technical means or operating arrangements.

   (5) Anomalous or infrequent propagation modes. No protection is
   provided against interference caused by tropospheric and ionospheric
   propagation of signals.

   (d) Harmful interference to SDARS operations requiring resolution. The
   following conditions will be presumed to constitute harmful
   interference to SDARS operations from WCS operations in the 2305-2320
   MHz and 2345-2360 MHz bands and require WCS operators to work
   cooperatively with SDARS operators to address areas where such power
   levels are exceeded and harmful interference occurs:

   (1) A WCS ground signal level greater than -44 dBm in the upper or
   lower A or B block, or -55 dBm in the C or D block, present at a
   location on a roadway, where a test demonstrates that SDARS service
   would be muted over a road distance of greater than 50 meters; or

   (2) A WCS ground signal level exceeding -44 dBm in the upper or lower A
   or B block, or -55 dBm in the C or D block on a test drive route, which
   is mutually agreed upon by the WCS licensee and the SDARS licensee, for
   more than 1 percent of the cumulative surface road distance on that
   drive route, where a test demonstrates that SDARS service would be
   muted over a cumulative road distance of greater than 0.5 percent
   (incremental to any muting present prior to use of WCS frequencies in
   the area of that drive test).

   [ 62 FR 9658 , Mar. 3, 1997, as amended at  78 FR 9621 , Feb. 11, 2013]

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