§ 87.479   Harmful interference to radionavigation land stations.

   (a) Military or other Government stations have been authorized to establish
   wide-band systems using frequency-hopping spread spectrum techniques in the
   960-1215  MHz  band.  Authorization  for  a Joint Tactical Information
   Distribution  Systems  (JTIDS)  has  been  permitted  on  the basis of
   non-interference to the established aeronautical radionavigation service in
   this band. In order to accommodate the requirements for the system within
   the band, restrictions are imposed. Transmissions will be automatically
   prevented if:

   (1)  The frequency-hopping mode fails to distribute the JTIDS spectrum
   uniformly across the band;

   (2) The radiated pulse varies from the specified width of 6.4 microseconds
   ±5%;

   (3) The energy radiated within ±7 MHz of 1030 and 1090 MHz exceeds a level
   of 60 dB below the peak of the JTIDS spectrum as measured in a 300 kHz
   bandwidth. The JTIDS will be prohibited from transmitting if the time slot
   duty factor exceeds a 20 percent duty factor for any single user and a 40
   percent composite duty factor for all JTIDS emitters in a geographic area.

   (b) If radionavigation systems operating in the 960-1215 MHz band experience
   interference or unexplained loss of equipment performance, the situation
   must be reported immediately to the nearest office of the FAA, the National
   Telecommunications and Information Administration, Washington, DC 20504, or
   the nearest Federal Communications Commission field office. The following
   information must be provided to the extent available:

   (1) Name, call sign and category of station experiencing the interference;

   (2) Date and time of occurrence;

   (3) Geographical location at time of occurrence;

   (4) Frequency interfered with;

   (5) Nature of interference; and

   (6) Other particulars.

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