An FM Microwave Radio Relay

The design features of an experimental 8,000-8,500-mc radio relay are reviewed. The technical innovations mentioned are the result of research and engineering accomplished for the design of a military radio-relay system. A duplexing antenna system comprised of a waveguide hybrid tee, a waveguide mast structure, an off-center fed parabolic reflector antenna assembly, and a waveguide cavity preselector for the receiver is described. A mechanically and electronically tuned cw communications magnetron, which provides a carrier power in excess of 50 watts, is included and is capable of being frequency modulated. A unique frequency stabilization circuit maintains the carrier center frequency, improves the linearity of the modulation, and reduces the carrier-noise frequency variations.