A Look at a 1950s-era AM Radio Transmitter

For those who don't know, I work for a local group of radio stations as a broadcast engineer, and one of the stations I maintain is an AM with a facility dating back to 1946.  This is a tour of the station's old RCA BTA-5G transmitter, which was installed in 1955 when the station (under its first owner) upgraded from 1kW to 5kW.  I will admit I'm a little fuzzy on some of the details of this transmitter's operation (and this sort of old-school circuit design in general), but I explained it as best I could at the time.  I probably screwed up some details, but such is life.


Something else I should have noted in the video is that this transmitter is powered from two separate circuits in the building's electrical system.  One is the 3-phase 208V supply that I describe in the video, while the other is a single-phase 110V supply that only powers the crystal heaters, in-cabinet lights, and in-cabinet convenience outlets.  The latter supply is supposed to always remain on so that the crystals are always held at operating temperature, even when the transmitter is off.  So no, the circuitry that I reached in and pointed at was not energized.