UHF-TV klystron multistage depressed collector development program

摘要

This report describes a program to incorporate depressed collector technology into UHF-TV klystron power amplifiers. The program objective was to develop a klystron with enhanced efficiency where power consumption would be reduced to half in TV service. A design was achieved using computer-aided design technology. Also developed were carbon coating techniques to minimize the adverse effects of secondary electrons. An experimental 60 kW klystron was constructed and evaluated. The collector design uses four stages operating at equally spaced depressed potentials. Current distribution to the collector electrodes was measured and power recovery determined. The magnitude of regeneration was also determined, and the effectiveness of secondary electron suppression was noted. The performance results indicate 74 percent power recovery with no rf output reducing to 57 percent at saturation representing an overall efficiency of 71 percent. Regeneration was low enough to allow stable operation with up to 60 dB gain.