1922 AM Transmitter

1922MarPM1A hundred years ago this month, the March 1922 issue of Popular Mechanics carried the full construction details for this AM transmitter for the radio amateur. Heretofore, constructing such a transmitter was an expensive proposition, since it invariably required a motor-generator to provide the high voltage. This transmitter, however, used a “new type of transformer” to supply the 500 volts of B+ from household current, “as simply as screwing in a lighting bulb or plugging in an electric iron.” Two rectifier tubes could be of “any of the various types on the market,” and the transmitter itself used three UV-202 tubes.

The price of all of the parts was said to be about $125. According to this inflation calculator, that works out to over $2000 in 2022 dollars, so this was not the project for the impecunious.

The article noted that the exact range would, of course, vary with local conditions. But the author reported that music and voice had been transmitted from 100 to 200 miles, and under especially good conditions, an extreme range of 500 miles had been recorded.

The author, whose later call sign was W9DCX, went on to become the magazine’s radio editor. He died in 1955, as noted in his obituary in the magazine.

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