A signal measurement system tests an RF component in an RF test facility, such as an RF anechoic chamber. The system includes a repeater which is connected to an exterior antenna disposed outside the chamber and a transmitting antenna disposed inside the chamber. The repeater receives the RF broadcast signal from the exterior antenna and rebroadcasts it as an RF testing signal inside the chamber. The subject antenna receives the RF testing signal, which is then analyzed with a computer. The repeater may also modify the RF testing signal to produce a wide variety of test situations that mimic those available in a traditional field-test.