Seventy-five years ago this month, the July 1942 issue of Popular Mechanics carried the plans for this simple one-tube regenerative receiver. The set was designed with wartime parts shortages in mind, and most parts were non-critical, and could be found in most junk boxes.
Future issues of the magazine would carry improvements, and most parts would be reused. In addition, the suggested breadboard layout was such that there would be room for more advanced designs to be built on the same board.
The set used a single 1Q5GT tube. It used one flashlight battery to run the filament, with four in series to provide the 6 volts B+. A battery eliminator was promised for the next issue.
Coils were wound on the cardboard tubes salvaged from D cell flashlight batteries. The article called for an external antenna and ground. Tuning was accomplished by setting regeneration to maximum, and then tuning until a squeal was heard. At that point, you would turn down the regeneration control just enough to listen to the station.