SDR++

[ChrisSmolinski]

After using SdrDx for ages with my netSDR, ever since I got my first SDR, an SDR-IQ, SdrDx has finally stopped working after a macOS update (Sonoma). It had a good run.

I've switched to SDR++ as it seems to do most of what I want.  I'm also running Gqrx on this machine (M1 Mini) with an AirSpy Discovery, monitoring 27700 USB for SSTV.

I'm curious if there are any other SDR++ users here, as I still have a few questions:

The number of built in sample rates for the RF Space netSDR is rather lacking: 200, 400, and 800 kHz. Is there any way to add additional sample rates? The netSDR supports arbitrary sample rates, within some parameters. Previously with SdrDx I used 250 kHz and I'd like to go back to that if possible.

The only AGC settings I see are attack and decay. They don't have any units displayed. Based on the range of values, neither seconds nor milliseconds seems to make a lot of sense. Or at least they're rather narrow. I didn't see AGC slope or threshold values, I assume they don't exist?

I could not find a way to get it to write consecutive I/Q baseband files. It seems to just write one file each time you start and stop recording. I was able to get around that by writing my own little app that leverages its built in rigctl server, to start and stop recordings every 30 minutes. Kinda kludgy, but it works.

I'll probably have more questions 

[RobRich]

Let me preface this reply by stating I have little experience with modern MacOS and pratically none with NetSDR. I rarely use SDR++ either. So a huge YMMV here.

I suspect you using the SDR++ native rfspace module to interface with the NetSDR, correct?

https://github.com/AlexandreRouma/SDRPlusPlus/blob/master/source_modules/rfspace_source/src/main.cpp

If so perhaps instead try using the SoapySDR NetSDR module, assuming you have SoapySDR and its NetSDR module setup on your system. The module appears to have several default sample rates listed; including 250.

https://github.com/AlexandreRouma/SDRPlusPlus/blob/master/source_modules/soapy_source/src/main.cpp#L196
https://github.com/pothosware/SoapyNetSDR/blob/master/NetSDR_Settings.cpp#L754

[ChrisSmolinski]

I'm using the pre-built binary version of SDR++

After writing software all day, the last thing I want to do is develop more code 

[RobRich]

I get the feeling, though I suspect all you really need to do is install SoapySDR. :)

That would mean getting SoapySDR installed on your system if not already deployed. There appears to be Homebrew scripts for MacOS here:

https://github.com/pothosware/homebrew-pothos?tab=readme-ov-file
https://github.com/pothosware/homebrew-pothos/wiki

Since it is part of the source tree, the SDR++ binary build should already have the needed support to interface with the required SoapySDR module.

[cyphermatic]

...the last thing I want to do is develop more code 

Hi Chris! 

You run a nice set of KiwiSDRs over there in Md. I'm an ex Baltimorean; haven't been back in a long time.

The good news on SoapySDR is this work should be pretty painless.  RobRich is onto something here. I'm just a lowly RTL-SDR user, but just finished setting up a bunch of SoapySDR drivers for the new Skywave Linux 5 / Debian Sid. With the cloning and building commands in a Bash script, Soapy goodies installed faster than I could go and pour a cup of coffee and come back to the machine.

SDR++ is developing well, with plenty of updates coming out on the nightly branch.  The last time I checked, the focus was on getting the PlutoSDR module running better. I use 'plusplus often for tuning my RTL dongle and also playing KiwiSDR IQ recordings.