Collocation of receivers and high-power broadcast transmitters

Receiving antennas and receivers can be collocated with the transmitting antennas and transmitters, if appropriate interference suppression is effected. Since the time-varying characteristics of the interference from adjacent transmitters may not be known a priori, and since the propagation path characteristics may change with time, interference needs to be suppressed by adaptive means. Operational characteristics of the adaptive control system in a shortwave broadcast station and expected degree of cancellation of the unwanted interference are discussed. Some recent tests to evaluate the effectiveness of the adaptive control in the relay station of Voice of America at Delano, California are outlined. Both laboratory and field tests show that adaptive interference-suppression systems can be designed and built for real-life environments expected in broadcast and relay stations