If you ever look at construction notes for building old detector type radios the type of headphones specified always have an impedance of 2 × 2000Ω. Nowadays the most commonly available headphones ...

I am just finishing a new transmitter facility at the Empire State Building and there were a couple of times that I needed power supplies to keep various relays energized (like remote interlocks) or ...

We are used to microwave receivers requiring complex chipsets and exacting PCB layouts, but as [CHZ-soft] has shown, it does not always have to be that way. With nothing more complex than a germanium ...

Radio experimenters often need a variable capacitor to tune their circuits, as the saying goes, for maximum smoke. In decades past these were readily available from almost any scrap radio, but the ...