Sec.  25.261   Procedures for avoidance of in-line interference events for Non
Geostationary Satellite Orbit (NGSO) Satellite Network Operations in the Fixed
Satellite Service (FSS) Bands.

   (a) Applicable NGSO FSS Bands. The coordination procedures in this section
   apply to non-Federal-Government NGSO FSS satellite networks operating in the
   following assigned frequency bands: The 28.6–29.1 GHz or 18.8–19.3 GHz
   frequency bands.

   (b) Definition of “In-line interference events.” For purposes of this
   section, an “in-line interference event” is defined as the interference
   associated with an occurrence of any physical alignment of space stations of
   two or more satellite networks with an operating Earth station of one of
   these networks in such a way that the angular separation between operational
   links of the two networks is less than 10 ° as measured at the Earth station.

   (c) Default procedure. If no agreed coordination exists between two or more
   satellite networks, then the bands will be divided among the affected
   satellite networks involved in an in-line interference event in accordance
   with the following procedure:

   (1) Each of n (number of) satellite networks involved in a particular
   in-line interference event shall select 1/n of the assigned spectrum
   available in each frequency band for its home base spectrum. The selection
   order for each satellite network shall be determined by and be in accordance
   with the date that the first space station in each satellite network is
   launched and operating;

   (2) The affected space station(s) of the respective satellite networks shall
   only operate in the selected (1/n) spectrum associated with its satellite
   network, its home base spectrum, for the duration of the in-line
   interference event;

   (3) All affected space station(s) may resume operations throughout the
   assigned frequency bands once the angular separation between the affected
   space stations in the in-line interference event is again greater than 10 °.

   (d) Coordination procedure. Any coordination procedure agreed among the
   affected operating satellite networks, which allows operations of the
   satellite networks when each network's respective space stations are within
   the 10 degree avoidance angle associated with an in-line interference event,
   shall supersede the default procedure of paragraph (c) of this section.
   Coordination may be effected using information relating to the space
   stations and the parameters of one or more typical earth stations. All
   parties are required to coordinate in good faith.

   [ 68 FR 59129 , Oct. 14, 2003]

Subpart D—Technical Operations

   Source:    58 FR 13421 , Mar. 11, 1993, unless otherwise noted.