Jerrold TV-FM
Jerrold Electronics was founded by Milton Jerrold Shapp (later governor of Pennsylvania) in 1948, and this booster was the first product. It was designed by grad student Don Kirk and built in a small factory in Philadelphia. It was a popular item -- between 250,000 and 500,000 units were sold, making Jerrold the biggest producer of boosters for a while. Production ended about 1952. Jerrold went on to be a founder of the cable TV industry and is a major player in that business today.
The circuit of the TV-FM is simple, "a reasonably cheap copy" of an RCA TV set's tuner, to use Don Kirk's words. A series of tapped coils and a fine-tuning capacitor tune the input of a 6AK5 tube, with the plate circuit broadly tuned with another tapped coil set. Ten switch positions covered all 12 TV channels and the FM radio band. Later "Series B" models (about 1949) included a switchable impedance-matching output device called a "Match-A-Tran" which was mounted on the back. Literature with the booster claimed gain of 20 to 30 dB, "without the slightest trace of regeneration" (undesired oscillation). A transformer and selenium rectifier provided necessary operating voltages for the tube.
The bakelite cabinet is said to have been from a bedside clock. The single control knob (with fine-tuning wheel) was unusually simple for early boosters, and no doubt contributed to its popularity.
Updated March 29, 2007