Amateur radio repeater

An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. Many repeaters are located on hilltops or on tall buildings as the higher location increases their coverage area, sometimes referred to as the radio horizon, or "footprint". Amateur radio repeaters are similar in concept to those used by public safety entities (police, fire department, etc.), businesses, government, military, and more. Amateur radio repeaters may even use commercially packaged repeater systems that have been adjusted to operate within amateur radio frequency bands, but more often amateur repeaters are assembled from receivers, transmitters, controllers, power supplies, antennas, and other components, from various sources.

In amateur radio, repeaters are typically maintained by individual hobbyists or local groups of amateur radio operators. Many repeaters are provided openly to other amateur radio operators and typically not used as a remote base station by a single user or group. In some areas multiple repeaters are linked together to form a wide-coverage network, such as the linked system provided by the Independent Repeater Association which covers most of western Michigan, or the Western Intertie Network System ("WINsystem") that now covers a great deal of California, and is in 17 other states, including Hawaii, along with parts of four other countries, Australia, Canada, Great Britain and Japan.

Repeaters are found mainly in the VHF six meters (50—54 MHz), two meter (144—148 MHz), 1.25-meter band (1 1/4 meter) (220—224 MHz) and the UHF 70 centimeter (420—450 MHz) bands, but can be used on almost any frequency pair above 28 MHz. Recently,33 centimeters (902—928 MHz) and 23 centimeters (1,240—1,300 MHz) are also being used for repeaters. Note that different countries have different rules; for example, in the United States, the two meter band is 144—148 MHz, while in the United Kingdom (and most of Europe) it is 144—147 MHz.

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