Late in 1937, as W2XMN was nearing completion,
Armstrong ordered 25 FM receivers, at $400.00 each, from GE.
These receivers would be used to demonstrate FM around New York.
These were the first production FM receivers, and the first FM
receivers built outside of Armstrong's lab.
General Electric would be the first company to obtain a license
to manufacture FM receivers under the Armstrong patents,
presenting Armstrong with his first FM royalty check for $22.66
in December of 1937.
The audio chassis was designed to take advantage of FM's wide
frequency response, using P-P 6L6's and a huge (for the time)
output transformer. The receiver chassis is clearly first run -
several types of pre-production GE tubes are used (e.g., XP332
and XP333).
Frank Gunther, retired president of REL, and REL engineer in
those years, recently stated that upon receipt of the receivers
from GE none would operate. The trouble was apparently in the RF
front-end, as the RF enclosure was initialed by Armstrong in
several places - beside notes such as 'tested 4/21/38'.
One of the 25 GE receivers.
This tag was found tied under one of the front panel knobs. This particular receiver was entered as an exhibit during one of the post-war patent infringement suits.
