For decades, amateur radio’s digital voice landscape on VHF and UHF was dominated by a handful of proprietary systems. That changed in 2019 when Wojtek SP5WWP and a small group of hams started the M17 Project with a simple but radical goal: create the first fully open-source digital voice and data protocol specifically designed for amateur radio, from the ground up.
Today, M17 is no longer a curiosity. It is the fastest-growing open digital mode on 2 m and 70 cm, with repeaters on every continent (including Antarctica), handhelds shipping from multiple vendors, and an ecosystem of software, firmware, and hardware that is 100 % license-free and patent-free.
What Makes M17 Different?
M17 uses the free and open-source Codec 2 speech encoder-
Feature | D-STAR | System Fusion | DMR | M17 |
|---|---|---|---|---|
Codec | Proprietary AMBE | Proprietary AMBE | Proprietary AMBE | Open-source Codec 2 (3200 bps payload) |
Modulation | GMSK | C4FM | 4FSK | 4FSK (9k6 symbol rate) |
Protocol | Closed | Closed | Open Standard (ETSI) | Fully open (OSI layers 1–3 specified) |
Licensing | Vendor-locked | Vendor-locked | Royalty-bearing | GPLv3 / CC-BY-SA |
Over-the-air encryption | No | No | Yes (proprietary) | Yes (AES-256, optional) |
Simultaneous voice+data | Limited | Yes (V/D mode) | Yes (Tier II) | Yes (3200 bit/s data stream) |
Standalone hardware | Only vendor | Only vendor | Many clones | OpenHR20, TYT MD-9600 M17 firmware, Module17, etc. |
The killer feature is M17’s ability to utilize Codec 2 for high-quality, royalty-free digital voice. The Codec 2 payload carried by M17 is 3200 bits per second (bps), which provides voice and Forward Error Correction (FEC). M17’s overall system design is optimized to match or exceed the intelligibility of proprietary codecs in weak-signal conditions. Most people who hear M17 on a repeater say it sounds competitive with Fusion or D-STAR in good conditions, and its robust error correction provides better performance in weak-signal conditions.
The Stack – Truly Open From RF to Application Layer
- Physical layer: 4FSK at 9600 baud, 12.5 kHz channel spacing compatible (fits in a normal 12.5 kHz FM channel in most countries).
- Data link layer: Stream or packet mode, Golay(24,12) and punctured convolutional FEC, 16-bit CRC.
- Network layer: IPv4/IPv6 tunneling built in.
- Application layer: Voice frames, text messaging, APRS-like position reporting, and an extensible “metadata” field for future uses.
- 100 % patent-free, royalty-free, and open-source.
Everything is specified in the openly published M17 RF Protocol Specification (currently v2.0.3). Want to write your own repeater controller? The reference implementation OpenRTX runs on a $4 STM32.
Hardware You Can Buy (or Build) Today
Refer to this table: https://wiki.m17foundation.org/index.php?title=Hardware_Projects
The fact that a $40 Chinese handheld can be turned into a fully featured M17 radio with nothing more than a USB cable and free software is a game-changer.
The Network Is Growing Fast
As of this writing:
- > 320 M17 repeaters worldwide listed on m17project.org
- >120 reflectors (the M17 equivalent of DMR talkgroups) with M17Worldwide (REF001) regularly carrying 24/7 traffic
- Native linking to YSF rooms, DMR talkgroups, and even D-STAR reflectors via multi-protocol gateways
- Experimental AX.25 over M17 (3200 bit/s packet radio inside an M17 stream)
Why This Matters for the Future of VHF/UHF
- Cost collapse
A full-featured M17 handheld that used to cost $500–700 now costs $200–250, and the price is still falling. - Resilience
No single vendor can kill the mode by abandoning it. The entire ecosystem is community-maintained. - Legal certainty
Codec2 and the protocol stack are free of known patent encumbrances. In an era when AMBE patent royalties are rising, this is huge.
The Future of Voice and Data Comms on VHF/UHF
Where Is M17 Heading Next?
The future of VHF/UHF digital comms isn’t proprietary. It’s open, it’s free, and it’s already here.
The roadmap for 2026–2027 is aggressive: Some of the goals for now are to release v3.0.0 of the specification along with the LinHT handheld (making it production-ready). Learn more about the M17 roadmap by going to the source: https://m17foundation.org/
In short, Codec2 is not just “good enough” compared to the 25-year-old proprietary codecs we’ve been stuck with. In many real-world scenarios, it is objectively superior — and it belongs to the amateur radio community forever. That is why M17 repeaters are multiplying so quickly: hams finally have a digital voice system that is technically excellent, completely open, and impossible for any corporation to take away.
This article is full of inaccuracies and AI hallucinations. Please fix it.
Fixes applied. Sorry for the hiccup.