For the past day and a half, I’ve been attending the GNU Radio Conference 2021 in my capacity as Content Manager for ARDC. There’s a lot of stuff that’s flying over my head, but I’m learning a lot as well. One idea that I can’t shake is why more hams aren’t using GNU Radio.
There are a lot of cool things about GNU Radio:
- It’s open source and free to use.
- It runs—at least that’s what they tell me—on inexpensive computing platforms, such at the Raspberry Pi 4.
- There’s a graphical user interface for developing GNU radio applications, which makes programming much easier.
Perhaps one reason is that it’s not that easy to set up and use. Nine months ago, I tried getting started with GNU Radio on a Raspberry Pi 4. My results were a bit disappointing to say the least. I keep threatening to get working on this project again, but I always seem to find an excuse not to do it. I’d guess that other hams are in the same boat.
Another reason perhaps is that while many of us know what digital signal processing (DSP) is, and are aware of the advantages of DSP, making radios with DSP is hard. You do need to know some of the mathematics behind DSP and what techniques to use in particular situations. If you think the math on the Extra Class test is hard, then DSP is going to be a real brain buster.
Perhaps I’m wrong, and there are a bunch of GNU Radio projects out there in the amateur radio world. If so, I’d love to know about them.
Let’s just say for the moment that I’m right. What do we need to make GNU Radio more popular and used in the amateur radio world? The first thing I think we need is more basic DSP training. Again, if there are course out there—perhaps on Coursera or some similar learning platform—please let me know.
Second, I’d say we need a “GNU Radio for Dummies.” This book/online course/set of videos would not only introduce hams to GNU Radio, but use as an example some simple radio, say a 70 cm FM transceiver.
The hardware for this training course could possibly be the ADALM-PLUTO. This devices has a frequency range of 325 MHz to 3.8 GHz, and Analog Devices says, “[The ADALM-PLUTO] helps introduce electrical engineering students to the fundamentals of software-defined radio (SDR), radio frequency (RF), and wireless communications. Designed for students at all levels and from all backgrounds, the module can be used for both instructor-led and self-directed learning to help students develop a foundation in real-world RF and communications that they can build on as they pursue science, technology, or engineering degrees.” What’s more GNU Radio has very good support for the ADALM-PLUTO.
Software-defined radio is the future of radio…including amateur radio. It behooves us to learn about this technology, if only to be able to use it more effectively. I’d also say that we should learn about it so that we can fulfill out purpose of “advancing the state of the radio art.” GNU Radio could be a big part of that.
sinclair says
Not everyone likes tinkering or coding, even among Hams I find the number to be a minority. I have no interest in SDR, and have no plans to touch GNU Radio. When I want to get on the air I want to be able to sit down turn the radio and and key up, not worrying about potentially debugging code (My rig is a Kenwood TS-140S that I inherited from my grandfather who bought it new.). Plus in my area HOAs are king so most Hams are busy trying to just get a usable antenna up, last thing we need to be worried about is a SDR acting up. Call me a stick in the mud, but I’m getting tired of everything seeming to move to software defined and use your smart phone as the control.
Tom says
My problem has been the lack of binaries for the latest versions, and the lack of support for the rtl-sdr dongles. Unless you have a full dev environment it’s hard to get started.
I’d like to do more with GR, but end up bogged down getting the environment set up.
Dan KB6NU says
The version I was running under HamPi and PiSDR had a block for connecting RTL-SDR dongles.
Bob says
There are lots of tutorials on how to setup without binaries. OsmoSDR and SoapySDR are available to interface with Gnuradio and are included (just search within GnuRadio for RTL-SDR).
Kd1mu says
I think with gnu radio there may be too many moving pieces. First I have to get the raspberry Pi working, then I have to build the radio / DSR, then I have to figure out how to use gnu radio, then I need to get an sample radio working.
Maybe we need an SDR board that interfaces to a raspberry pie and has an example radio in order to get started. Does this exist.? Hams venturing into DMR can buy an MMDVM and a Pi to get started. Maybe something similar would help. I wouldn’t know where to start with GNU radio.. I know that it was easy for me to start with openwrt and opengd77 because I began with the hardware already assembled. The same with MMDVM. I would be game to try,, what do I need to do to get an Adam-Pluto set up?
Dan KB6NU says
This is an interesting thought. The ADALM-PLUTO costs $210 from either Mouser or Digi-Key. Perhaps someone could come up with a GNU Radio-specific build for the RPi that has the radio flowgraph with everything all tested and working. They could sell the entire kit including an RTL-SDR dongle for people just getting started.
A kit with the ADALM-PLUTO, or some other more capable SDR hardware could be available for a higher price.
Dave New, N8SBE says
There is a GNU Radio specific .iso that can be loaded onto a USB thumb drive, and booted if your PC BIOS supports booting from USB (most modern BIOSes do). This will boot a Linux OS with GNU Radio already pre-installed. Of course, running from USB Flash is slow, so it will be something you can try out without re-formatting or re-partitioning your PC drive, but you will likely want a better installation to work with, if you want to explore further.
I’ve also loaded Ubuntu on a laptop as the sole OS, and GNU Radio is available in the Ubuntu ‘store’, to download and install. The problem is that the package available with most Linux OS installs is out of date, and if the installed version differs from the current distribution even by a minor version, it can break all your scripts, etc.
Finally there is a semi-automated installation system that can put you on the bleeding edge, so that you can use the latest scripts and plug-ins. There is a fairly steep learning curve to use it, but there are walkthroughs in the GNU Radio Wiki.
GNU Radio is a very rich, powerful system for developers and experimenters. It’s not really aimed at folks that just want to run SDR-based radios with point and shoot GUIs. Applications like SDR# and others are more suitable for folks that want to play with SDRs, but don’t want to get into the bits and bytes of SDR programming itself.
Martin Rothfield says
An order to presenting this is:
– introduction to signals
– signal processing
– digital signal processing techniques
– GNUradio
The mathematical foundation for all of this is overwhelming but the underlying principles should be within the grasp of hams.
GNUradio has always been tricky for me to set up. I wish the developers would push out stable, bootable images as suggested previously to improve the experience.
Another reason to buy an ADALM-PLUTO is the free SATSAGEN spectrum analyzer and signal generator tool. It’s not a Fieldfox, but is fine for many applications.
Here are some (mostly) gnuradio based projects (poorly documented) from the past: https://www.meetup.com/Cyberspectrum/events/past/
Bob says
I highly recommend the HackRF website lessons on SDR. https://greatscottgadgets.com/sdr/