Sec.  25.259   Time sharing between NOAA meteorological satellite systems and
non-voice, non-geostationary satellite systems in the 137–138 MHz band.

   (a) A non-voice, non-geostationary mobile-satellite service system licensee
   (“NVNG licensee”) time-sharing spectrum in the 137–138 MHz frequency band
   shall not transmit signals into the “protection areas” of National Oceanic
   and Atmospheric Administration (“NOAA”) satellite systems. When calculating
   the protection areas for a NOAA satellite in the 137.333–137.367 MHz,
   137.485–137.515 MHz, 137.605–137.635 MHz and 137.753–137.787 MHz bands, a
   NVNG licensee shall use an earth station elevation angle of five degrees
   towards the NOAA satellite and will cease its transmissions prior to the
   NVNG licensee's service area, based on an elevation angle of zero degrees
   towards the NVNG licensee's satellite, overlapping the NOAA protection area.
   When calculating the protection areas for a NOAA satellite in the
   137.025–137.175 MHz and 137.825–138 MHz bands, a NVNG licensee shall use an
   earth station elevation angle of zero degrees, or less if reasonably
   necessary, towards the NOAA satellite and will cease its transmissions prior
   to the NVNG licensee's service area, based on an elevation angle of zero
   degrees towards the NVNG licensee's satellite, overlapping the NOAA
   protection area. A NVNG licensee is responsible for obtaining the necessary
   ephemeris data. This information shall be updated system-wide on at least a
   weekly basis. A NVNG licensee shall use an orbital propagator algorithm with
   an accuracy equal to or greater than the NORAD propagator used by NOAA.

   (b) A NVNG licensee time sharing spectrum in the 137–138 MHz band shall
   establish a 24-hour per day contact person and telephone number so that
   claims of harmful interference into NOAA earth station users and other
   operational issues can be reported and resolved expeditiously. This contact
   information shall be made available to NOAA or its designee. If the National
   Telecommunications and Information Administration (“NTIA”) notifies the
   Commission that NOAA is receiving unacceptable interference from a NVNG
   licensee, the Commission will require such NVNG licensee to terminate its
   interfering operations immediately unless it demonstrates to the
   Commission's reasonable satisfaction, and that of NTIA, that it is not
   responsible for causing harmful interference into the worldwide NOAA system.
   A NVNG licensee assumes the risk of any liability or damage that it and its
   directors, officers, employees, affiliates, agents and subcontractors may
   incur or suffer in connection with an interruption of its non-voice,
   non-geostationary mobile-satellite service, in whole or in part, arising
   from or relating to its compliance or noncompliance with the requirements of
   this paragraph (b). The Commission will not hesitate to impose sanctions on
   a NVNG licensee time-sharing spectrum in the 137–138 MHz band with NOAA,
   including monetary forfeitures and license revocations, when appropriate.

   (c) Each satellite in a NVNG licensee's system time-sharing spectrum with
   NOAA in the 137–138 MHz band shall automatically turn off and cease
   satellite transmissions if, after 72 consecutive hours, no reset signal is
   received from the NVNG licensee's gateway earth station and verified by the
   satellite. All satellites in such NVNG licensee's system shall be capable of
   instantaneous shutdown on any sub-band upon command from such NVNG
   licensee's gateway earth station.

   [ 62 FR 59296 , Nov. 3, 1997]