47 CFR § 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.