Eighty years ago this month, the April 1939 issue of Popular Science showed how to put together this simple one-tube regenerative receiver.

The set employed a 25A7GT tube, which combined rectifier and pentode. The article noted that the set had a range of about a thousand miles on the broadcast band, but the parts list called for “a set” of plug-in coils. So there’s no reason why the set, with appropriate coils, couldn’t pull in shortwave signals.

The set uses the familiar “curtain burner” line cord to step down the filament voltage. Also, if you’re considering building such a set, there is an important safety reminder. Depending on which direction the line cord is plugged in, there’s a possibility that the chassis is hot. Even if you use a polarized cord to make sure the chassis is neutral, then the rectified line voltage is hooked directly to the headphones. So if you plan to recreate this particular set, please use extreme caution.