One hundred years ago this month, the April 1923 issue of Popular Science carried the plans for this one-tube regenerative radio receiver, which was said to be able to pull in concerts from a hundred miles away. The total cost, including headphones, was under twenty dollars. And if the reader already had a crystal set, especially one with a variocoupler, the cost could be further reduced.

And the $20 figure was for store-bought parts. Someone good with tools could make some of the parts themselves, saving even more money. For example, the variocoupler could be home built, as could the condenser and even the tube socket.  The switches shown here are commercially made, but they could also be fabricated at home from brass screws.

Tuning was accomplished with taps on the coil, and regeneration was adjusted by rotating the small coil.