Frequency-Modulation Transmitter and Receiver for Studio-to-Transmitter Relay System

A complete studio-to-transmitter system for high-fidelity program relaying between the studio and the main transmitter is described. The entire equipment was designed considering simplicity and reliability to be of prime importance. Several installations have been in successful operation for over one year. The 25-watt transmitter incorporates several novel features which account for the excellent performance obtained. Newly designed tubes especially suited for ultra-high-frequency operation are used. A crystal-controlled, double-conversion superheterodyne receiver, employing such features as cascade limiting, carrier-off-noise suppression, and vertical-chassis construction is also described. Harmonics from the same crystal oscillator are used in performing both conversions, resulting in an extremely stable unit. Both transmitter and receiver may be remotely operated when proper compliance is made with Federal Communications Commission regulations. A high-gain studio-to-transmitter antenna, which meets all Federal Communications Commission requirements, is totally enclosed against the weather to avoid ice-melting problems. A frequency-modulation station monitor indicates center frequency continuously, as well as per cent modulation and carrier level. Aural monitoring is also obtained from the same unit.