[QRP Gaijin] likes to build regenerative receivers. If you’ve ever built a serious one, you know there are (at least) two problems: One is you need a variable capacitor (hard to find these days). The ...

Crystal radios used to be the “gateway drug” into hobby electronics. Trouble was, there’s only so much one can hope to accomplish with a wire-wrapped oatmeal carton, a safety-pin, and a razor blade.

The circuit has been designed to function as amplifier-detector to produce high quality of audio output through the external earphone. The circuit has been designed to function as amplifier-detector ...

From the receiving side of the circuit, the antenna was made of random wire coupled with the inductor L1 having a single turn while inductor L2 has 4 turns wound around a 35 mm film container. Both ...

Also called a "regenerative receiver," a radio receiver that detects and demodulates the carrier frequency broadcast by the station without using an intermediate frequency (IF) stage. The homodyne ...

Sixty-one years ago, on January 31, 1954, Edwin Armstrong, who invented the regenerative, super regenerative, and superheterodyne detector circuits for continuous-wave and amplitude modulation and the ...