EARLY TRANSISTOR HISTORY AT RCA Gerald B. Herzog – First Transistor Television Oral History – (Continued)
Curator’s Note: The Following Material is a Continuation the Gerald Herzog Oral History, and Details His Work on the First Transistor Television, Developed in 1952 at RCA Labs. For the Complete Herzog Oral History, Use This Link: Go To Complete Herzog Oral History Starting on the Transistor Television Project. After Bob Lohman and I demonstrated the curve tracer to some fascinated visiting engineers from Bell Labs, I joined Bob working for George Sziklai. George proposed building a television set using transistors as a demonstration of what might be possible in the future. However, he met a lot of resistance because, after all, no transistors could operate anywhere near the frequencies that were necessary for a regular TV set. However, George persevered and the project was approved. Bob Lohman and myself started working with George on the design of the set. I started working on the RF section first because of my radio frequency experience in the past. Bob worked on complementary symmetry audio circuits with George. The set was to be a single channel set with a loop antenna so it would be portable for demonstration, and of course battery operated. I decided I had to know how much signal was available in the Princeton area for channel 4, so I set up a dipole antenna with a tuned circuit, a crystal rectifier and a micro-ammeter.	I took this outside and was amazed at the strong signal I observed on the meter. What I didn’t realize was that the diode was acting as a photo-detector and driving the meter. In fact, the signal in Princeton was very, very weak and very elaborate antennas were necessary for the TV sets in the area at that time. But since I had no TV set myself, I didn’t realize what the situation was. We ultimately set up a transmitter in the demonstration room that rebroadcast channel 4 for the demonstration. Building the set, of course, was difficult because of the very poor performance of the transistors available in those days. For the local oscillator, I used one of the point contact transistors that was basically unstable, since we wanted it to oscillate anyway. For the IF section, I used TA166 point contact transistors that were sometimes stable. I selected units that would work best in the circuit I had. It took six stages at 7.5 MHZ (megacycles in those days) as a center frequency. It then took an additional four stages at 4.5 MHZ for the sound IF. However, the RF section was easy compared to finding transistors that could deliver enough current to drive the picture tube yolk and withstand the high voltage involved. Go To Herzog Oral History, Page 10
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