Westinghouse Radio Station at Saxonburg, Pa.

Westinghouse Radio Station KDKA, at Saxonburg, Pa., was built to provide up-to-date equipment for regular broadcasting and for high power experimental work on either long or short waves. Power equipment consists of a 12-phase, 900-kw, 30-kv rectifier using three-anode mercury pool type tubes; a 6-phase, 450-kw, 22-ky rectifier; four 10-kw, 3-kv motor generator sets for bias and intermediate amplifier plate supply; six 40-kw, 40-volt motor generator sets for filament power; a 400-volt storage battery for small tube plate voltage and for substation control; and two 12-volt, 1600-ampere-hour storage batteries for small tube filament supply. Present transmitter apparatus includes a 300-kw output stage using six Westinghouse type AW-220 tubes; a 5-kw intermediate power amplifier; a modulator for the 5-kw stage, a crystal control and intermediate amplifier unit; a high level modulator with provision for six AW-220 tubes for experiment or modulating the output stage operated class C; and a 50-kw power amplifier for regular broadcasting using six water-cooled tubes plate modulated by a transformer coupled class B push-pull modulator. The four audio circuits to the studio in Pittsburgh go underground for several thousand feet to prevent r-f pick-up. The cooling water system employs heat interchanges.