Transistor Museum Lecture Hall

Mr. Thomas Stanley  

 

The First RCA Transistor Radios

by Thomas Stanley

 

Dave Holmes, drawing on a paper about vacuum-tube amplifiers written in the thirties, pointed out that "maximum available gain" as a measure of transistor performance meant little; he defined "maximum stable gain", which made practical the heretofore mysterious process of high-frequency circuit design.   Many at RCA Laboratories were by now developing transistor circuits.  Our common objective was a grand several-days show-and-tell for RCA licensees and industry leaders.  We'd patched together a guitar amplifier, a personal pager, and a phonograph amplifier.  Loy Barton contributed a much improved “personal portable” radio. Most spectacular, hands down, was the transistorized TV set that Jerry Herzog and Bob Lohman had built under the guidance of George "complementary-symmetry" Sziklai.  They ingeniously used point-contact transistors where the needed high-frequency performance was beyond that of junction transistors, and an oscilloscope-like display, but it was nonetheless spectacular.  For this show-and-tell, reject transistors had been glued to poster   boards.  Fortuitously, we later discovered that while these transistors had failed some static tests, they exhibited unusual high-frequency performance when suitably operated.  We retrieved them, and many found their way-- still with glue and cardboard skin on one side-- to the r-f and mixer stages of our radios.  And radios it was.  We were called upon to replicate our elegant personal portable radio by a half-dozen or more for various big wigs. 

 

      

 

The First RCA Transistor Radios

by Thomas Stanley

 

None, though, for Larry, Dave or me; management had not yet heard the maxim "Thou shalt not muzzle the ox that treads the corn" that Bill Webster was fond of invoking years later, when he deservedly became boss.  After the personal portable, we engineered an automobile radio, meeting or exceeding the test specifications of a top-of-the-line auto radio then in production. Engineers from the manufacturer (not RCA) came to see what we'd done.  We showed comparison performance curves, including some that were fairly arcane.  In one such side-by-side comparison, our guest engineer pointed out that the illustrated performance would never do, until he was alerted that he was speaking of his own product.  We were told that an auto radio must be operable over a temperature range from 40 below zero to 80C above.  Ours was, with only moderate loss in performance at the extremes.  The old, leaky test chamber in which we made these measurements accommodated a brew of dry ice and cellusolve acetate, and Larry became deathly ill for a day and a half from the fumes.  Our last hurrah, years after the Herzog-Lohman triumph, was a twelve-inch portable TV that could compete with any small commercial set.  As I recall, for the high-frequency circuits we may by then have had the benefit of the drift transistors that Bill Webster, now in our Semiconductor Division, was turning out.  Horizontal deflection was a challenge-- the yoke was direct-driven-- but Joe Preisig ultimately succeeded with a circuit that stacked two transistors. 

Go To Stanley, Page 4

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