In the days of crystal-controlled radios, these pairs were identified by the last portion of the transmit (Input) frequency followed by the last portion of the receive (Output) frequency that the ham would put into the radio. The actual frequency pair used is assigned by a local frequency coordinating council. In the USA two-meter band, the standard offset is 600 kHz (0.6 MHz), but sometimes unusual offsets, referred to as oddball splits, are used. Repeater frequency sets are known as 'repeater pairs', and in the ham radio community most follow ad hoc standards for the difference between the two frequencies, commonly called the offset. 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 144–146 MHz. In some areas, 33 centimeters (902–928 MHz) and 23 centimeters (1.24–1.3 GHz) are also used for repeaters. Repeaters are found mainly in the VHF 6 meter (50–54 MHz), 2 meter (144–148 MHz), 1.25-meter band (1 1⁄ 4 meters) (220–225 MHz) and the UHF 70 centimeter (420–450 MHz) bands, but can be used on almost any frequency pair above 28 MHz. 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. 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 amateur radio, repeaters are typically maintained by individual hobbyists or local groups of amateur radio operators.

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.

Amateur radio repeaters are similar in concept to those used by public safety entities (police, fire department, etc.), businesses, government, military, and more.

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'. Coaxial cavity RF filter at 2 meter repeaterĪn 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.

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