Twenty-Watt Aircraft Transmitter

A transmitter for aircraft employing cw telegraph signals only is unusually effective in performance and economical in operation. By employing a special method of screen-grid modulation, phone signaling can be provided for use when phone signaling is most needed-namely, when flying in the vicinity of airports-with almost negligible additions to the cw transmitter. A rapid transfer of information is mostly needed at or near an airport. Short-range phone signaling provides for this need. When flying on regular courses, telegraphy is rapid enough. Cw telegraph signals remain 100 per cent intelligible under conditions which would be near O intelligibility for the same power phone signals.