Short Wave Uses
Common uses of the shortwave radio band are:
The most common use of all is international broadcasting by government-sponsored propaganda stations to foreign audiences.
Domestic Broadcasting uses Widely dispersed populations with longwave, mediumwave, and FM Stations. These are used for specialty political, religious
and alternative media networks, individual commercial and non-commercial paid broadcasts
Utility stations for aircraft flying between continents, encrypted diplomatic messages, weather reporting, ships at sea
Clandestine stations that broadcast for various political movements, including rebel or insurrectionist forces, normally unauthorized by the government. These transmissions may originate from within rebel-controlled country or outside of the country altogether via another country's transmission facilities. These were used during WWII to transmit news from Allied points of view into Axis-controlled territories.
Numbers Stations deliver broadcasts containing nothing but recited blocks of numbers in various languages with occasional bursts of music. They are unlicensed and untraceable. They regularly appear and disappear all over the radio band and is believed they are operated by government agencies communicating with clandestine operatives in foreign countries. No proof is available to prove this. These stations regularly appear and disappear all over the shortwave radio band but are unlicensed and untraceable. It is believed that Numbers Stations are operated by government agencies, and are used to communicate with clandestine operatives working within foreign countries. However, no definitive proof of such use has emerged.
Amateur radio operators.
Time signal and radio clock stations: In North America, WWV radio and WWVH radio transmit at these frequencies: 2500 kHz, 5000 kHz, 10000 kHz, and 15000 kHz; and WWV also transmits on 20000 kHz. The CHU radio station in Canada transmits on the following frequencies: 3330 kHz, 7850 kHz, and 14670 kHz. Other similar radio clock stations transmit on various shortwave and longwave frequencies around the world. The shortwave transmissions tend to be intended primarily for human reception, while the longwave stations are generally used for automatic synchronization of watches and clocks.
Over-the-horizon radar: From 1976 to 1989, the Soviet Union's Russian Woodpecker over-the-horizon radar system blotted out numerous shortwave broadcasts daily.