1BCG Transmitter in 1921

The 1BCG transmitter, as originally built, used two UV-204 Radiotron tubes in a self-excited, self-rectifying Colpitts oscillating circuit. It was rebuilt in the field into a master-oscillator, power-amplifier (MOPA) arrangement, to avoid the disadvantages of a self-excited oscillator and to produce a pure, steady CW signal. The single-204 oscillator was direct coupled to three more 204s in parallel in the amplifier. A motor-generator set supplied 2000 V dc for the plate voltage.

1BCG Circuit in 1921
A type UV-204 triode

After the successful completion of the tests, the 1921 1BCG transmitter was removed to Columbia University for exhibition at a reading of a paper by the Radio Club of America. It is unknown what happened to the transmitter after that event.

1BCG Antenna in 1921

The antenna was a 100-foot horizontal cage flattop, made up in two sections each 50 feet long with eight #14 stranded phosphor-bronze wires that were equally spaced around 18-inch-diameter metal hoops and connected from the center point with a 70-foot cage downlead.
There was also a counterpoise consisting of 30 radial wires, each 60 feet long. The radials extended from a common central point, at a height of seven feet above the ground. To reduce resonance effects, the counterpoise had two equal fan-shaped halves, each with 15 wires.

The 1BCG Antenna in 1921
The 1BCG Antenna Counterpoise in 1921

1BCG Crew in 1921

The 1BCG crew assembled at the shack. Left to right: Ernest V. Amy, John F. Grinan, George E. Burghard, Edwin H. Armstrong and Minton Cronkhite. Missing is Walker P. Inman.