Seventy-five years ago this month, the November 1945 issue of Radio Craft carried this circuit for a simple one-tube receiver for the broadcast band. The set used either a type 30 or 1G4 tube, with as little as 3 volts B+ on the plate. The circuit had been sent in to the magazine by Bill Buehrle, Jr., of Ferguson, MO, who reported that he was able to pull in a half dozen stations clearly from 25 miles away.

Even though the circuit was published after V-J Day, it’s likely that it was perfected while the War was still in progress with its attendant parts shortages. The author points out that parts weren’t critical. In addition to the tube and headphones, the circuit required only six manufactured parts, two resistors, two fixed capacitors, and two variable capacitors. The coils and the RF choke could be wound at home.

The circuit could be easily duplicated today. The tube is still readily available on eBay. The type 30 and the 1G4 are electrically identical, but my preference would by the 30, since its glass has the classic styling of the 1930’s era bottle, as opposed to the more “modern” octal style 1G4.   It’s such a simple set that it would form the basis for an excellent science fair project. And with only 3 volts involved, it would even be a safe project. The original article contains some suggestions on how the circuit could be modified, so comparing some of these modifications would make the project very worthwhile.  The young scientist needing to track down the parts will find some helpful leads on my crystal set parts page.