I am creating this topic to discuss various problems that we have on gr-osmosdr and GNURadio (and also gqrx) when it comes to RSP support.
We can discuss solutions and then some of us can help in fixing them by proposing our own changes via pull requests, or creating issue/ticket on the respective project's page.
I don't know whether these are universal problems, or only I have encountered these.
Here are some of my problems:
1- You cannot use sample rates below 2Msps in gr-osmosdr (and GNURadio)
It is hard-coded in "get_sample_rates" function in "sdrplay_source_c.cc"
Note: editing this value is not enough (I tried that and didn't work. Just got overflows/underflows)
2- You can use "sdrplay" directly in GNURadio, but not via the "soapy" driver (using soapy causes buffer overflows with constant "aUaUaUaUaUaU..." prints in output). Though you can use SDRPlay both directly and via soapy in Gqrx.
3- When in GNURadio, you cannot set gains for SDRPlay via the osmocom source (am I missing something here?)
I've been able to set LNA_MIX_BB gain in osmocom_fft, but it does not work in GRC.
4- I don't know how to explain this. Look at the difference between SDRPlay's waterfall and another SDR (in this case AirSpy R2) in GNURadio's "WX GUI FFT Sink". For sampling rates above 2Msps, SDRPlay's waterfall is strange (does not show other frequencies that are there; i.e. in a crowded band like BCFM)
It's a very simple flow graph; Just a "osmocom Source" connected to a "WX GUI FFT Sink":
SDRPlay at 10Msps:
AirSpy at 10Msps:
I've fetched all the sources and compiled them to make sure I'm using the latest fixes etc.
Here are the versions FYI:
Code: Select all
GNURadio 3.7.11 gr-osmosdr v0.1.4-98-gc653754d (0.1.5git) Gqrx v2.9-4-g4138038 OS : Mac OS X 10.13.2 (on a MacBook Pro 13" 2015) Soapy: Lib Version: v0.6.1-g4daa4329 API Version: v0.6.0 ABI Version: v0.6