This article first appeared in Echo Ireland and was written by Jeffrey Roe.
The following is less of a how-to and more of a journey of me learning about DMR and getting started.
DMR, what is it?
Digital Mobile Radio (DMR) is a digital radio standard for voice and data transmission in non-public radio networks. It’s different from the analogue radios some of you might be more familiar with. It doesn’t transmit using FM in the traditional sense, but uses a digital signal.
DMR has a few tiers, and the technology originally targeted the commercial market (around 2012). It works a bit like a phone network, with every radio having its own ID, and it can even support sending SMS over the network.
With a few rule changes in 2014, the FCC paved the way for amateur radio use. The widespread availability of Raspberry Pi hotspots helped DMR use to explode, making it easy to bridge a handheld radio onto talkgroups across the internet. RadioID (RadioID.net) looks after the coordinated DMR identification numbers for hams.
The radio that started it all
Now, back to my story. During the summer of 2025, I was gifted a Tytera TYT MD-390 DMR handheld radio (new old stock). The fellow Tog member who gave it to me had plans to get into radio, but life got in the way.
I was interested in trying it out because it claimed IP67 waterproofing, which sounded perfect for cycling trips. At the time, I knew nothing about DMR, but that radio kicked off the journey.
A tip from Tog and a firmware rabbit hole
During one of the monthly social nights in Tog Hackerspace, I got chatting about this new-to-me radio. Daniel EI8ICB made some great suggestions. It turned out he had used the same model before. To convert it for amateur radio use and make things a little easier, he suggested I look at MD380 Tools: https://md380.org/
This firmware patch adds some very useful features, such as promiscuous mode, USB logging, and Morse code narration. The big plus, though, is the callsign database you can load onto the radio.
The downside? The firmware flashing can’t be done via the cable in the box. It requires a custom USB-to-accessory connector. Daniel, being well ahead of me on this one, already knew the pinout and sent me a wiring diagram.
Making The Cable
I had some leftover parts from an SSTV project, including some connectors from AliExpress. I thought this would be an easy evening job, but it wasn’t to be.
After tracing the wires with a multimeter, it turned out the connectors I had didn’t match the pins I needed. I didn’t want to wait weeks for replacements, so I went digging around Tog’s electronics room to see what we had on hand.
The male USB connector was an easy find, and so was the 3.5 mm jack, but I had to dig deep in the “jack pile” to find a 2.5 mm jack. In the end, I cut up what looked like a custom cable from an old digital camera. A little soldering and heat-shrink later, I had a working cable.
MD380 Tools in practice
It’s possible to install and compile all the tools required to build the firmware patch, but the project also provides a VM image. Think of a VM as a program that runs a whole operating system inside your laptop. In this case, a Linux environment with everything pre-installed and ready to go.
With VirtualBox installed on my Ubuntu laptop, flashing the radio was straightforward. More importantly, it proved my soldering worked, and I now had a much more ham-friendly handheld.
Hotspots: Getting on the network
DMR radios work best when they can reach other DMR radios. You can do this via a DMR repeater. You can see what’s around Ireland on the IRTS gateway page: https://www.irts.ie/cgi/gateway.cgi
But none were near me. The next best thing is an MMDVM hotspot. You can think of these as a bridge from RF to the internet, and back again.
A fellow Tog member( Conor EI9JYB) was also interested in DMR, so we turned to AliExpress and ordered a couple of hotspots. I picked one intended to pair with a Raspberry Pi Zero, an inexpensive single-board computer I already had a few of.
In the meantime, thanks to the power of Mastodon, someone offered me another TYT radio after seeing me talking about soldering my own cable. Brilliant. That gave both of us a reason to get stuck into DMR together.
The kits arrived and needed a bit of soldering, so off I went to visit Kilcock on the bike for a day of cycling, soldering, and radios.
A little tangent here: we even called into the Sunday 2 m news using a heavy 10 W handheld. I had to climb up on a wall to be heard, but it was a fun way to start the day.
Hotspot Software
The default software for many MMDVM hotspots is Pi-Star: https://www.pistar.uk/
I loaded it onto the Raspberry Pi Zero, but the problems started quickly. I found the whole thing very slow and not particularly straightforward to use.
After a few YouTube videos, the internet suggested I try a newer project that’s actively developed: WPSD: https://w0chp.radio/wpsd/
WPSD promised easier setup and more features, but it didn’t support my very old Pi Zero. It needed more RAM and processing power. It did support the Raspberry Pi 3, and I had a few of those lying around from a donation to Tog.
Installation was much smoother, and the interface made more sense. It also guided you through registering on RadioID and BrandMeister.
With everything set up, my Raspberry Pi cases wouldn’t fit because of the SMA connector, but Dremel made light work of that problem.
Radio programming
Now, the journey wasn’t over yet. I still had to configure the handheld with contacts and talkgroups.
The usual programming option for my analogue handheld, CHIRP, was out of the question because it doesn’t support DMR radios. I turned to qDMR for Linux: https://dm3mat.de/software/qdmr
Next question: who to call for a first test? I asked in the Online Amateur Radio Club Discord (https://www.oarc.uk/) if anyone would take a call. Thanks to Robin M0JQQ for answering my request.
With their DMR ID in hand, I used qDMR to configure the radio and was ready for my first QSO on DMR.
It worked \o/
Wrapping up
Thanks for reading my story if you got this far. I’m hoping to explore more of what DMR has to offer over the coming months, and you might even see a follow-up article.
In the meantime, you can find my radio and cycling adventures on Mastodon:
https://chaos.social/@tdr112
For more photos of the build, check out our gallery. https://www.tog.ie/gallery/nggallery/album/dmr-radio-project
