25 kw Tacan Transmitter Assembly

摘要

TACAN is an aircraft-to-ground beacon navigation system which provides to aircraft, over large areas, the azimuth angle and the range of the aircraft to the ground beacon. This report describes the work that was accomplished towards the development of a 25-kilowatt peak power TACAN transmitter ground beacon using negative grid tubes. A technique for obtaining a desired output spectrum from an RF amplifier by making an envelope comparison with a stable reference was postulated. The use of this technique would allow a TACAN Transmitter to be constructed without the spectrum control filter that is currently used. This program has shown it is possible to control a transmitter spectrum by the use of this feedback technique. The test results obtained at 22 kw were sideband ratios of 48 to 49 db. Subsequent to the suspension of this program additional tests were performed at a 13-kw level. The amplifier was constructed of a chain of ceramic coaxial tetrodes. The tubes are capable of delivering the desired output power of 25 kilowatts. Operating with low, fixed plate and screen voltages results in a very small pulse modulator and a reduction in d-c power requirements. A broadband frequency multiplier was developed which simplifies tuning procedures in changing the transmitter from one operating channel to another.