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Over-The-Horizon Radar is a military radar system deployed by the United States in various places outside the continental USA. In recent years, interference assumed to be from these systems has been widely noted in the shortwave pirate and amateur radio bands, primarily around the area of 7 MHz. The sound of these systems on typical shortwave receivers sounds like a loud, wideband chirping, and older listeners liken the sound to the Russian Woodpecker, a similar HF radar system of Soviet design.

Official WRC OTHR over the horizon radar bands

The allocations below 30 MHz are generally considered a fixed/mobile service - fixed service.

The 41.015 MHz to 41.665 MHz and 43.35 MHz to 44 MHz bands may be secondary depending on a specific country's radio allocations (as they are both above 30 MHz and considered VHF bands).

The 41.015 MHz to 44 MHz band is allocated to the fixed/mobile service on an international basis.

In the United States, the band is allocated to several VHF low sub-bands:

  • 40.00 MHz - 42.00 MHz Military land mobile, fixed, Government land mobile, fixed, fixed/mobile
  • 42.00 MHz - 42.95 MHz Land Mobile - Public Safety, Government land mobile, military land mobile
  • 42.95 MHz - 43.19 MHz Land Mobile - Business Radio Service, military land mobile
  • 43.19 MHz - 43.69 MHz Land Mobile - Public Safety, Military land mobile, Business Radio Service
  • 43.69 MHz - 44.61 MHz Land Mobile - Business Radio Service, military land mobile

See also

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