Going to be trying a few other SDR.
Raspberian OS and compiled on the RaPi4 (before putting into RASPAD3).
RX only. SDRPlay (version 1)
RX and TX. Lime Mini SDR and Adalm Pluto SDR (found it)
I use an external USB 3.0 powered hub with these.
I expect will also try the DragonOS for the RaPi as well.
I have an SDR and an HF upconverter (basically an RTL dongle) so you can sample down to about 50Hz is needed, will try that was well.
update: 20th October 2021
I added the software for the Lime Mini SDR and the Pluto SDR, going to be taking a copy of the SD card before do anything else.
Last night checked both the speaker and audio out connections with a simple music WAV file playing in a loop. Didn't want RF issues.
Note: SDR++ used was the source build 1.0.4 obtained from https://github.com/AlexandreRouma/SDRPlusPlus/releases and compiled on the RaPi (see this blog post for details) https://m1kta-qrp.blogspot.com/2021/10/installing-gqrx-and-sdr-on-raspberrypi.html
What it could do when was version V1.0.0 this is what AlexandreRouma at the time:
SDR++ v1.0.0 Released!
Hi everyone :)
After over a year of work, I'm proud to released version 1.0.0 of SDR++!
For those who don't know, SDR++ is a crossplatform (Windows, Linux, MacOS, BSD) and open-source (https://github.com/AlexandreRouma/SDRPlusPlus/releases) general purpose receiver software meant to be simple and easy to use. It has advances features like multi-vfo and uses a fully custom DSP making it very efficient.
Here are the following additions compared to the last version:
Support for the SpyServer protocol
Support for all SDRplay devices
Support for all BladeRF devices
Support for all LimeSDR devices
Optional IQ correction
Broadcast FM Stereo
Frequency manager to create lists of frequency and optionally display them directly on the FFT/Waterfall
Network sink to stream the audio output via TCP or UDP
Options to set the FFT framerate, FFT size and FFT window.
Theming with Dark and Light themes supplied by default
RigCTL server module to control SDR++ from, for example, gpredict.
A bunch of keyboard shortcuts (see wiki on the github page)
More info when hovering a VFO
Colored VFOs to easily identify which is which at a glance
Meteor M2 demodulator compatible with LRPTOfflineDecoder and Satdump
Ability to resize VFOs by directly dragging the sides on the FFT and waterfall
Module manager to easily add or remove any module on the fly without having to restart or edit the config manually
File dialogs to select directories in the recorder or files in the file source (instead of having to type in the path)
Ability to disable modules that support it (Radio and Meteor M2 demodulator) with one click (to save CPU power or just if they're not needed)
Lots of performance improvements
Ludicrous amounts of bugfix :)
I'd like to thank the many contributors, patrons and companies (SDRplay, Airspy, Nuand, LimeMicro) who helped make this project possible!
If you have any issue with the software, please open a github issue or contact me directly on the SDR++ discord (see readme on github)
I hope this software comes in useful to at least some of you ;)