A broadcast relay station, satellite station, relay transmitter, broadcast translator (U.S.), rebroadcaster (Canada) or repeater (two-way radio), Complementary station (Mexico), is a broadcast transmitter which repeats or transponds the signal of another radio station or television station, usually to an area not covered by the signal of the originating station. They may serve, for example, to expand the broadcast range of a television or radio station beyond the primary signal's coverage area, or to improve service in a part of the main coverage area which receives a poor signal due to geographic constraints. These transmitters may be (but are not usually) used to create a single-frequency network. They may also be used by a radio station on either AM or FM to establish a presence on the