Quisk – A software defined radio for Linux

Few days ago I learned about the Quisk software defined radio application for Linux. It is written by James Ahlstrom N2ADR with contributions from other radio amateurs around the world. A quick glance at the home page and the documentation suggested that it is a rather simple application where it is easy to add support for other hardware.

I like simple so I decided to take a quick look at it and investigate the possibility of adding UHD support. UHD is the Universal Hardware Driver for the USRP family hardware by Ettus Research. Quisk already comes with support for soundcard, Softrock, and SDR-IQ, which suggests that adding support for new hardware should be relatively easy.

Quisk is distributed as source package and it is written in Python and C. The latter requires compilation. The Quisk manual describes which packages must be installed in order to compile it and all these packages should be available in any Linux distribution, i.e. there are no exotic requirements. There is no automatic build configuration so you have to check for yourself that your system has the required dependencies. Once you have done that compiling is as simple as typing “make” in the top level Quisk folder. It will compile for a few seconds and then ready to go!

A great feature in Quisk that I really appreciate is that I could evaluate by simply compiling it and executing it. Unlike pretty much all other SDR software out there, it doesn’t require hours of configuration just to get it up and running. Just start it and it comes up using a default sound card as input device

Quisk SDR reading input fro the sound card

I didn’t have anything connected to the sound card so all I got was noise, still this allowed me to get a feeling of the application, press buttons, etc. Now I can dive in and take a closer look.

Another fun feature in Quisk is the waterfall. It is really a waterfall in that you can see the samples/drops fall from the top of the waterfall for a few lines where after they start scrolling normally. You can see it on the screen shot below in that the points are longer at the top. It is really fun to watch in real time 🙂

Combined waterfall and FFT scope in Quisk SDR

I will now try to spend some time and see if I can make it work with UHD, so stay tuned!