Thread for gr-osmosdr and GNURadio problems/ideas

[Sasan]

Hi
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

Does anyone have similar problems?

[DK7OB]

I am running gqrx with RSP1(A) via the soapy drivers without problems.

I was playing with gnuradio some time ago and I also used the soapy via gr-osmosdr without problems. I can check this next week after Christmas when I have some spare time.

I found the direct sdrplay support in my gr-osmosdr build (with the NON_FREE build option) was not up to date compared to the soapy driver. Maybe there is a gr-osmosdr fork with better SDRplay support somewhere.

Regarding the "aUaU...": Do you get no audio at all or a crackling audio with the "aUaU" correlated to the cracks?

As far as I remember, I got audio problems only with high sample rates (probably due to high load USB)

Forgot to mention: I am running Linux (Ubuntu 16.04).

[Sasan]

I was playing with gnuradio some time ago and I also used the soapy via gr-osmosdr without problems.

I can use Soapy on Gqrx, but not in GNURadio.

Regarding the "aUaU...": Do you get no audio at all or a crackling audio with the "aUaU" correlated to the cracks?
As far as I remember, I got audio problems only with high sample rates (probably due to high load USB)

No I didn't have any audio; And I was testing with 2Msps !

I found the direct sdrplay support in my gr-osmosdr build (with the NON_FREE build option) was not up to date compared to the soapy driver. Maybe there is a gr-osmosdr fork with better SDRplay support somewhere.

Thanks; I just found out that I was using the "gr-osmosdr-fork-sdrplay" and that's why it was working.
I installed the original "gr-osmosdr" and it does not work anymore, so I switched to the fork (the latest update to the fork seems to be made on April)

[Sasan]

I will create a list of differences between Soapy's and gr-osmosdr's implementation.
We can use that to improve the situation on gr-osmosdr (hopefully)

[jsalsburg]

If anyone can post how to get GRC to work with my RSP1A, I will be grateful.

The window for the SDRplay is blank because GNURADIO is not setup for SDRplay nor will it until someone figures out how to do this. At the time of the reply it appears no one has figured out how to get the SDRplay RSPs to work (properly) in GRC. If you were to examine the text Pane in the GRC Window, you will notice that GNU Radio is not access the SDRplay hardware. I was told to use SoapySDR which works for the GUI App "CubicSDR " but this does not seem to help GRC. I must stress that GQRX and CubicSDR are GUI Apps, they are end products with a limited usefulness for product development.

[DK7OB]

What is your platform? I have the RSP1A running in GRC with Ubuntu 16.04 right now.
It's an old flow graph I built for the RSP1 but it is still working with the RSP1A.
Gnuradio and osmosdr are built from source. I am using the osmocom source with the properties below:

Screenshot_20171230_151056.png (46.32 KiB) Viewed 34359 times

current values:
frequ = 3550000
samp_rate = 250000
RFGR = 34
IFGR = 43
BBGR = 1