An Airborne VHF Transceiver without Moving Parts

This paper describes the design of a 25 watt transmitter-receiver which tunes through the range from 116 to 150 megacycles without moving parts. The receiver section employs varicap tuning and the oscillator-amplifier transmitter section is tuned by means of current variable inductors. Transmitter output frequency is controlled by a unique circuit which phase locks it to a reference frequency generated in the receiver crystal bank. This design brings about a reduction in size, weight and power requirements and greatly simplifies the over-all circuitry of the unit.