Gqrx with the Red Pitaya

Today it was brought to my attention that gqrx works well with the Red Pitaya board running the SDR transceiver code by Pavel Demin. Indeed, looking through the gr-osmosdr commit logs, I could see support was added in December 2015, just around the same time I was packaging gr-osmosdr.

To make it work, start with the official Red Pitaya image. The SDR transceiver code can be installed through the Red Pitaya application marketplace. There are two versions and we need the one that is compatible with GNU Radio.

Once installed, we can launch the SDR transceiver application through the web interface, though this is not much fun since it will only run as long as you have the web page open. Instead, we can launch the servers from the command line:

cd /opt/redpitaya/www/apps/sdr_transceiver
cat sdr_transceiver.bit > /dev/xdevcfg

The script will load and configure the FPGA, then launch both transceivers 1 and 2 using input/output 1 and 2 and network port 1001 and 1002 respectively. You can edit te script if you only want to start one transceiver.

There is also a script for stopping the transceivers.

Setting up a script for starting the transceiver(s) automatically at boot is left as an exercise, however, you can find inspiration in Pavel’s  code repository.

On gqrx side you will need to use the latest gr-osmosdr. I have already updated the myriadrf/gnuradio PPA and gqrx packages will follow shortly. You can still use the current gqrx 2.5 and 2.5.1 but you will have to enter the sample rate yourself.

Supported rates are: 20000, 50000, 100000, 250000, 500000 and 1250000.

In the device string enter the correct IP and port number. After that it should just work :-)

Gqrx running with the Red Pitaya

Gqrx running with the Red Pitaya

Gqrx running with the Red Pitaya

Author: Alexandru Csete

All-round nerd and space hacker. Known as OZ9AEC on the air.

  • Willi Kraml

    I tried to get gqrx (2.5.2 on OSX Yosemite) to work with my Red Pitaya, but failed miserably. Should Red Pitaya show as a device to use in the selection box? It doesn’t. Should it auto-detect the device? It doesn’t. I enter the IP address into the device string, but do not know the port number (so “In the device string enter the correct IP and port number. After that it should just work :-)” isn’t very helpful – where can i find the “correct” port number? Where is this documented? Whenever I enter sample rates, they magically disappear when I re-open the hardware config tab…. just doesn’t feel right either, and I do not get any audio at all.

    • Dear Willi,

      You can find the correct port number in the section that talks about starting the server. It is 1001 or 1002 depending on which transceiver you start.

      If Red Pitaya is not shown in the list of devices, then it is not supported by the backend. I will take a look and see if I need to update the gr-osmosdr library for the next release.

      Please understand, that it is very difficult for me to provide proper OS X support as I am only a single developer working in my spare time and only having sporadic access to a Mac. There will be rough edges, in particular when new devices are introduced. Helping me with testing and writing better documentation will in most cases improve things. Complaining and criticizing will not.

      • Willi Kraml

        Hello Alex, I didn’t mean to criticize your work, and I am willing to help as far as I can; I just am not sure where to start (not being a Mac developer). Setting IP and port 1001 or 1002 did not result in a signal showing on the display or in audio – strangely enough though, the signal strength indicator is constantly moving up and down. the receivers on teh red pitaya are running, at least their processes show up in the process table. But as you said, there might be aproblem with the backend, as it does not show the device in the drop down list. The only devices shown are: 4 RFSPACE devices, RTLSDR spectrum server, and complex sampled IQ file. Then there is “Other”, which allows me to enter free text into the device string (and I just entered IP and port there). Let me know if there is anything else I can do to pin the problem down….

        • I have uploaded a new bundle 2.5.2-3 with updated gr-osmosdr driver. This should now work with the Red Pitaya. Detection does not work, so after selecting Red Pitaya in the drop-down list, update the IP address and port if necessary.

          • Willi Kraml

            Great, Alex! It is working now! Thanks a lot for the extremely fast response!

          • Ok, thanks for the update. I should have v2.5.3 ready later this week.