Radio Theory and design

Inductance-Condenser-Design This is a link to the 1930s  correspondance course that trained a lot of radio men on into the 1970s. How to ...

Put an antenna coil on the variable cap. The tuning knob (red screw) adjust from about 7 - 10 Mhz. When I put the amp and antenna on I got...

This is the circuit I was playing with using the dipmeter as the LO.

 Building a tapped coil selector switch. I cut a thin slice from the end of a 3" x 3" block and laid out the taps every 30 de...

Using a grid dip meter as the LO and the hearing aid amp I'm driving a ring modulator circuit as a direct conversion receiver. Picked ...

I wanted a general purpose amp and built this one. The only thing I might would change would be to use a 100k pot for the input. With a si...

The question was asked. How to make a frequency doubler. Several answers were offered. The advice of one member was one test is better than ...