Disclaimer: I have not tried any of the following.? I am giving suggestions based on the information provided by QRP-Labs.
No RF or IF outputs are available on the QCX+ that an SDR Dongle could use.? ?A PC audio input could use two jumper locations as a tap point and feed to an SDR program that uses I/Q audio.? The I and Q audio are available at JP7 and JP8 per the schematic.? That would eliminate the SDR Receiver, with the I/Q audio sent via the RPi4 over ethernet to the PC.? The one potential issue with this setup would be sidetone generation.? The QCX+ Sidetone is generated by the ATmega controller and introduced into the Audio sections after the analog I/Q processing by the OpAmps.? The Sidetone would not be available unless a separate channel were set up.? There are possible delays between the audio and the keying of the QCX+.
The information for the details is in the manual for your QCX+.? There is a block diagram in Section 5.1 and a schematic in Section 5.2.??
Again a caution that I have not tested any of the above.
73
Evan
AC9TU
