Lots of Amateur Radio circuits

Here's a bunch of Amateur Radio circuit ideas, none have been tested!

A two SA612 receiver: The first is a mixer amplifier feeding the IF crystal filter, followed by a second as mixer/beat oscillator giving an audio output



An unusual receiver with a balanced detector, an audio amplifier and a local oscillator using a CMOS invertor



Here's a mixer using a CMOS switch. With as RF preamp and audio amplifier.



What could be simpler? a one transistor radio. With a balanced mixer and simple VFO



Now something different: an electronically tuned ATU, for receive only obviously.



Lastly an SWR meter, with easily wound torrid transformers

Torroids from torrid.info: