One of the most significant challenges digital has in ham radio is the multiple modes across manufacturers. D-Star, DMR, C4FM, P25 are all on the amateur bands across the United States, but could these digital modes we all know and use come to an end? If a new startup project has anything to say about it, the answer is yes.
The history of M17
The project is known as M17 and started in early 2019 to replace our current suite of proprietary digital voices modes. Amateur radio operators in Europe noted that there is no genuinely open, free-to-use digital radio system. M17 was born with over 100 ham radio operators and hackers around the world working on the project.
“The goal here should be to kick the proprietary protocols off the airwaves, replace DMR, Fusion, D-Star, etc. To do that, it’s not just good enough to be open, it has to be legitimately competitive.”– M17 Project
The manifesto is simple. M17 wishes to provide:
- Open-Source community
- Freely available and modifiable digital radio protocol
- Open hardware designs
Technical specs of M17 protocol
So how does it differ from things like DMR? M17 uses Frequency Division Multiple Access (FDMA) instead of Time Division Multiple Access (TDMA). FDMA, in the case of M17, allows for two 6.25kHz simultaneous links to be established on one 12.5kHz channel at 3200 bits per second. It’s using a Codec2 vocoder that M17’s developers say outperforms current proprietary vocoders currently on the market. Check out the full protocol specifications for M17.
Users are registered with the network using User IDs generated based on their callsigns. Base40 is used to encode the callsign into a 48-bit value. The user ID can be translated to a DMR Radio ID equivalent utilizing a lookup table.
When you look at the M17 hardware, you’ll find the TR-9 HT. The TR-9 can use FM voice or M17 digital pushing 3 watts of RF power via an ADF7021 chip, which is specifically designed for 4FSK modulation.
Which digital ham radio protocol is best?
Those that have talked to me know I’m not too fond of the D-Star protocol. I find the voice quality not up to par, and the registration process is an absolute nightmare.
I’ve been a Digital Mobile Radio (DMR) user for nearly seven years, and it has the same hurdles of not being user friendly. Then again, DMR was never intended for ham radio — so that’s no fault to DMR. It’s become wildly popular because of the cheap radios that have flooded the market from China. The affordable entry costs have floated DMR and the Brandmeister network to the top of the digital heap.
Then you have C4FM/YSF, which I find to be very enjoyable. It’s easy to use, and you don’t need to worry about a 100-setting codeplug to make it all work. If you can program an analog repeater, you can do C4FM/YSF.
Yaesu has been smart in selling their analog/digital repeaters cheap to spread the protocol, which has helped its popularity, but DMR is still more active across the board.
Is M17 good for ham radio?
Ham radio operators have been trying to solve the issue of multiple protocols for years, and M17 is yet another effort. But is that the long-term answer?
I would love to see a protocol emerge that all radio manufactures would get behind. The issue of differing protocols exists in public safety too, this isn’t just an amateur radio problem. We need to build a superior protocol and lobby the manufacturers to adopt it. Having protocols that use proprietary elements doesn’t help anyone — well, maybe the manufacturers.
I think the M17 is a fantastic project, and if you’re skilled and interested I would encourage you to get involved in the effort. M17 is looking for people with the following skills:
- C programming (Raspberry Pi, STM32, PC)
- PCB routing (preferably KiCAD)
- Familiarity with 3D printing, CAD/CAM
- Soldering, prototyping
- Open mind – concept testing
Let’s make digital ham radio great…. for the first time!