Setting up GNU Radio for use with the FreeSRP

Installing

The FreeSRP is supported in GNU Radio through gr-osmosdr. Prebuilt packages of gr-osmosdr for Ubuntu with FreeSRP support are available from the FreeSRP PPA.

If you are not using Ubuntu, you will have to build gr-osmosdr from source.

Ubuntu

In the Getting Started guide, you should already have installed libfreesrp and freesrp-firmware. Now, you will need to install GNU Radio, gr-osmosdr and other required dependencies. The easiest and most reliable way to do this is through the MyriadRF PPA. To add the required repositories and install GNU Radio with FreeSRP support, just run the following commands in a terminal:

sudo add-apt-repository -y ppa:bladerf/bladerf
sudo add-apt-repository -y ppa:ettusresearch/uhd
sudo add-apt-repository -y ppa:myriadrf/drivers
sudo add-apt-repository -y ppa:myriadrf/gnuradio

sudo apt update

sudo apt install gnuradio gnuradio-dev gr-osmosdr

Gqrx

If you wish to also install Gqrx, you need to add one additional PPA:

sudo add-apt-repository -y ppa:gqrx/gqrx-sdr
sudo apt update
sudo apt install gqrx-sdr

Building from source

Coming soon!

Testing your installation

You should now have GNU Radio fully set up and ready for use with the FreeSRP.

To try it out, start up GNU Radio Companion (GRC) from your main menu or run gnuradio-companion. To add a signal source from the FreeSRP, add the osmocom Source block to the flow graph. Double-click it to configure it. You will need to set the “Device Arguments” to “freesrp”. Now close this window, and set the sample rate higher (as the default of 32k is too low for the FreeSRP): double click on the Variable block with ID “samp_rate” and change the value to something between 1e6 (1 MSps) and 61.44e6 (61.44 MSps, the maximum). Trying a lower sample rate first, like 1 to 10 MSps is probably a good idea, as not every computer will be powerful enough to handle the higher, 40 MSps+ rates.

Now, add a QT GUI Sink block, and connect it to the osmocom Source. The GUI Sink is a graphical GUI output that you can use to verify the received signal.

For reference, the flow graph you end up with should look like this:

_images/grc_basic_flowgraph.png

Now, it is ready to be run. Click the Play button in the toolbar or press F6 to start it. After you save the flow graph, a window with the QT GUI Sink should pop up.