A control system and method for controlling switching between and among multiple antennas in a diversity antenna system comprising a radio head unit associated with a radio receiver; two or more antennas, either located in separate antenna modules or co-located in the same antenna module; a switch circuit; and a single cable. Control signals for controlling switching are provided as changes in a DC power supply signal carried on the single cable. In the case of multiple antenna modules, the radio head unit and the antenna modules are connected by the single cable using a daisy-chain architecture.