On 11/11/20 08:16, Chris Thompson via AMSAT-BB wrote:
The MFJ box looks nice, but you can do this with just an RF relay if you have one in the junk box. Maybe you have one lying around from an amplifier project that never quite got finished.. You could switch it with 12V and a toggle switch. I switch between an SDR and my 2m transmitter when FalconSat needs to be sent a packet. The TNC keys a sequencer which then switches everything over including the antenna. So the 2m antenna is only connected to the 2m radio when it sends a packet. The rest of the time it is connected to an SDR monitoring telemetry.
Also, one doesn't necessarily need a "RF" relay, if the band is 1.25m or longer:
https://www.w6pql.com/using_inexpensive_relays.htm
If you do want a "RF" relay, I use the Axicom HF3 relays in my 70cm LNA. They will handle 50 watts and seem to work well.
--- Zach N0ZGO