Eighty years ago, the January 1942 issue of Popular Mechanics showed how to put together this versatile circuit. It’s shown here serving as a phono oscillator, and can play records over the home radio. But it also served as a receiver for both the broadcast band and short waves. The set had a single coil, but it was tapped. For standard broadcast reception, the entire coil was used, but for short wave, most of the coil was shorted out. The set could drive a loudspeaker, although for shortwave use, high impedance headphones were recommended. A pilot light served as a fuse, to protect the tubes in case of short circuit.