In late 1938 the first commercial FM receiver, the REL Model 517, was produced. According to Frank Gunther, retired REL president, approximately 300 sets were manufactured (in 100 set runs). This set, weighing in at 45 pounds and selling for $315.00, was of exceptional quality, and was primarily intended as an FM station monitor (40 to 44 mc). The first two units off the production line went not to radio stations however, but went to the FCC. According to Mr. Gunther, the FCC had been searching for a means to monitor the expected flood of new FM station licensees - and the Model 517 was perfect.
This particular Model 517 is marked as being the personal property of John Bose, Columbia engineering graduate and Armstrong's right hand man from 1935 onward.
