Raspberry Pi SDR

[Chris D] noticed that the excellent software defined radio (SDR) software gqrx will run on the Raspberry Pi now. So he married a Raspberry Pi 3, a touchscreen, an RTL-SDR dongle, and an upconverter to make a very nice receiver setup. You can see the receiver in action below.

The video is a little light on build details, but there is a shot of the setup with the pieces labeled, and you should be able to figure it out from there. Of course, gqrx works with lots of different SDR devices so you might have to make adjustments depending on what you use (for example, many of the supported dongles won’t need the upconverter that [Chris] uses).

Experimental Raspberry Pi support for gqrx has only been in place since October of last year, but as you can see in the video, it appears to work quite well. Using a more powerful SDR module would make it even better, but be sure to check the gqrx site for information on what hardware is working with the Pi.

We’ve seen gqrx on a lot of different platforms,  and its features along with the wide range of SDR hardware supported, makes it a very useful tool, indeed. If [Chris] is looking for a neat case, we might suggest this. If you want to build SDR, but don’t want to use canned software like gqrx, we suggest GNU Radio.

11 thoughts on “Raspberry Pi SDR

  1. To clarify what was said regarding the necessity of an upconverter, any of the RTL-SDR dongles will need the upconverter if you’re interested in listening to the low bands. Depending on the chipset, they cut out between 60 MHz and 24MHz and go no lower. There are hacks for “direct sampling” them to get lower frequencies out, but the results are hit and miss and of generally low quality (the sensitivity takes a big hit). Putting an upconverter (such as Ham-It-Up or SpyVerter) in-line makes a big difference. I recently ran across an article about someone who built their own upconverter with a 6ME8 tube (old-school, represent!): http://www.rtl-sdr.com/using-a-beam-deflection-tube-as-a-mixer-for-an-rtl-sdr-upconverter/ , so there are a number of homebrew options out there to consider as well!

  2. Or, you could just use an Android tablet, connect the RTL-SDR stick to it, and run the app “RF Analyzer”.

    Maybe not as many bells and whistles as gqrx, but a much cheaper setup, and more portable.

    I use it all the time to troubleshoot rf hardware.

  3. Hello guys!
    thanks a lot for mentioning my video on your website and for all the suggestions! :)

    here are some more technical details about the project just in case that anyone is interested in:

    hardware:
    1. RPI 3
    2. 7″ official touchscreen for RPI – https://www.raspberrypi.org/blog/the-eagerly-awaited-raspberry-pi-display
    3. Cheap RTL-SDR TV dongle based on RTL2832U
    4. UpConverter is a custom-build based on TA7358AP – https://www.scribd.com/doc/207624956/Ta7358-Hf-to-Vhf-Upconverter

    software:
    1. Latest version of Raspbian OS
    2. GQRX 2.6 for RPI

    If I find some time my plan is to:
    – Build input controller with few switches and rotary encoder for tuning
    – Add front-end RF filters
    – Replace crystal oscillator in RTL-SDR dongle with some TCXO
    – Battery power
    – Put all the parts in some nice casing

    1. Is there a non-scribd version of that upconverter build somewhere? Scribd is basically the devil incarnate and I couldn’t find an alternate version of the PDF with a quick google.

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