The BC-191 is the epitome of a real transmitter; 4 x big tubes, real AM modulation, a 1920 radio design, lots of knobs, switches and meters. The BC-191 was designed as an easy-to-operate, reliable transmitter that could be used either in vehicles or in fixed locations.
The first AA-191 transmitters were built in the early thirties and used parts and technology from a decade earlier. Some early transmitters were installed on airplanes that at the time used a +12vdc power system. The BC-191 came about in the late thirties and was an upgraded version that had a better antenna tuner section which added to the versatility of the transmitter. Around the beginning of WWII, most aircraft were being built with +24 to +28vdc power systems and a modern airborne version of the BC-191 was necessary. The BC-375 became the designation for a slightly different transmitter that operated on +28vdc and was specifically for use in larger aircraft. General Electric got a manufacturing contract for the BC-375 and ultimately around 100,000 transmitters were built through most of WWII. (source: Radio Boulevard, Western Historic Radio Museum)
It uses four large 211 tubes. It operates on +14vdc and can be powered by the PE-53 dynamotor or it can also be operated using the AC powered RA-34 power supply. The BC-191 was used on Voice and Morse. There were other accessories for the BC-191 that allowed interfacing a telephone system into the transmitter.
Fixed and vehicular