1936: World’s Smallest Three Tube Set


Today, we offer this 80 year old miniature radio, which is barely visible.  The wearer is prolific radio writer Arthur C. Miller, who wrote the accompanying construction article.

He reported that the set, which used three miniature tubes, pulled in WCAU Philadelphia and WHAM Rochester from an office building in Midtown Manhattan. One of the tubes served as regenerative detector, with the other two serving as audio amplifier.

The antenna required some experimentation. The original idea was to wear it on the back, but the close coupling to the body meant that tuning and regeneration had to be readjusted after moving. Satisfactory results were obtained with the hat antenna, but the length required for the leadin added capacitance to the circuit, making the tuning range very narrow. He tuned the coil to 710 kHz, the frequency of WOR, and the set gave good results for WLW in Cincinnati on 700, and locals WEAF on 660 and WJZ on 760. He noted that by tapping the antenna coil, the tuning range could be increased.

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