A circuit that I found the other day…

Having shorted out the crystal, I doubt the circuit will oscillate. But you never know for sure. Maybe at VHF?

Another circuit I found recently was a sound card interface for a transceiver. It uses an opto-coupler to isolate the PC’s serial port from the radio…

Apart from the fact that in general there should be no need for isolation, the person who put this circuit together, forgot the RS232 specification…

So put a diode across pins 1 and 2 in the opposite polarity. Just to protect the opto-coupler.


Our recent Ham-Comp session, had more people visiting the club. More interested parties and some lessons learned. 

WSPR for the Raspberry Pi

The GitHub links:-