Seventy-five years ago this month, the April 1950 issue of Popular Science showed how you could, for about $2, convert your radio to pull in signals from Europe, Africa, China, and other locations. Specifically, it showed how to convert an “All-American Five” receiver to pull in shortwave signals.

The first step was to add a 4PDT (actually, a 3PDT would work, but weren’t generally available).  This was actually the trickiest part, since space might be tight.  The article cautioned that you might need to shop around to find one small enough.  With that done, you added the new wiring as shown below (in pictorial and schematic diagrams).  You added new antenna and oscillator coils to be switched in, and also added a terminal for an external antenna in series with a capacitor.

The last step was to add a dial scale to the front of the radio, which could be on a piece of cardboard.  The set would now tune 17 to 40 meters, and back to the standard broadcast band at the flip of a switch.