GNU Radio UDP sink is now under gr::network::udp_sink in the gnuradio-network module

[fventuri]

Hello,
I am running GNU Radio from the master branch here (version 3.10), and I noticed that gqrx does not build anymore because they moved the UDP sink block under gr::network::udp_sink (it used to be gr::blocks:udp_sink). They also added the GNU radio core module gnuradio-network where the UDP sink functions like gr::network::udp_sink::make() are defined.

I made a few changes to the gqrx source code and cmake config files to build it with the current GNU Radio master branch (v3.10.0.0git-429-g655e232a); after built it, I ran a quick test with gqrx here a few minutes ago, and I was able to receive a local FM station.

I just pushed my changes here: https://github.com/fventuri/gqrx/tree/network_udp_sink

If you are interested I can open a pull request to make gqrx build with the current GNU Radio master branch (version 3.10).

Regards,
Franco Venturi - K4VZ

[phaethon]

Thanks @fventuri ! I needed to use Master branch of GNU Radio because of PlutoSDR recently brought into it. With your patch gqrx compiles successfully.

[argilo]

I actually started some work on this already; see #958 for details.

I ran into a problem though: The UDP Sink block crashes if you stop & restart it: gnuradio/gnuradio#5112

I think GNU Radio will need to fix that bug before Gqrx can start using the new block.

[argilo]

Because the buggy UDP sink will be present in some released versions of GNU Radio (3.9.0 to 3.9.2), I should probably update my branch to switch to gr-network in 3.10 instead of 3.9.

[argilo]

@ulrichloose You may be interested in this topic, since you tested out my branch a while back (argilo@1b19970#commitcomment-50212951). I did a similar test just now and didn't have any trouble decoding pager traffic with multimon-ng. But I'll try making an I/Q recording and replaying it to see if there is any difference in the UDP packets between the old & new code.

[argilo]

But I'll try making an I/Q recording and replaying it to see if there is any difference in the UDP packets between the old & new code.

I tried this just now, and the outputs were identical, apart from the occasional rounding error in the least significant bit of a sample.

[fventuri]

@argilo - Clayton, first of all thanks for fixing this issue.

I built the latest GNU Radio from the master branch, then I built the 'gr-osmocom' module that supports SDRplay API version 3.X (https://github.com/fventuri/gr-osmosdr), and finally 'gqrx' from the repository master branch.
Everything compiled without errors, and I was able to run a quick test with gqrx to listen to a local FM BC station successfully.

Just a minor nitpick: I noticed that the README in this gqrx repository still refers to Alexandru Csete repository in the build instructions (and perhaps in other places); I was thinking that maybe they should be changed from 'csete' to 'gqrx-sdr'.

Franco

[argilo]

Thanks for pointing that out. I've opened #983 to update the URLs.