Practical Open Source Engineering: Forward Error Correction

#open #source #amateur #radio

Practical Open Source Engineering is a series of talks from the San Diego Chapter of Information Theory

This talk is an accessible explanation of the forward error correction in the M17 Protocol followed by a demonstration of the protocol's VHF/UHF amateur radio digital voice functionality. 

M17 is a community of open source developers and radio enthusiasts. 

M17 is developing a new digital radio protocol for data and voice, made by and for amateur radio operators. The voice mode uses the free and open Codec 2 voice encoder. This means there are no patents, no royalties, and no licensing or legal barriers to scratch-building your own radio or modifying one you already own.

This freedom to build, understand, and innovate is core to amateur radio, but has been missing from the commercially available digital voice modes. 

M17 can be adapted to space. Open Research Instititute actively supports both terrestrial and space development. Updates about testing M17 in space will be shared. 

The M17 Protocol can be used over RF with the following hardware or software implementations:

Module 17 is a smart-mic hardware M17 implementation running OpenRTX firmware (In Development)

TYT MD3x0 and clones with the OpenRTX firmware and a small hardware mod can be used with the M17 Protocol. (Experimental)

MMDVM hardware running the latest MMDVM firmware.

MMDVM_HS hotspots running the latest MMDVM_HS firmware. This includes serial based Raspberry Pi hats, and USB based dongles that run MMDVM_HS firmware.

  Date and Time




  • Date: 04 May 2022
  • Time: 07:00 PM to 09:00 PM
  • All times are (UTC-08:00) Pacific Time (US & Canada)
  • Add_To_Calendar_icon Add Event to Calendar
  • 3096 Harding St
  • Carlsbad, California
  • United States 92008
  • Building: Pine Avenue Community Center
  • Room Number: Community Room

  • Contact Event Host
  • Co-sponsored by Open Research Institute, Inc.
  • Starts 17 March 2022 09:45 PM
  • Ends 04 May 2022 09:00 PM
  • All times are (UTC-08:00) Pacific Time (US & Canada)
  • No Admission Charge


Michelle Thompson W5NYV Michelle Thompson W5NYV of Open Research Institute, Inc.


Forward Error Correction in M17 Protocol

M17 Protocol uses punctured convolutional coding and quadratic permutation polynomials for error control and bit stream re-ordering.

What does all of that mean and how do we use it?


Born in North Dakota, grew up in Arkansas, moved to live and work in California. I enjoy thinking and doing. Not necessarily in that order. I work with digital signal processing, software defined radio, MATLAB, GNU Radio, waveforms, and protocols. MSEE from USC and a variety of certifications ranging from Agile to RISC-V.

Amateur radio is why I became an engineer and is the motivation for a large amount of the volunteer work I do. I give back to ARRL, IEEE, DEFCON, and many other organizations. I founded Open Research Institute with Ben Hilburn and Bruce Perens in 2018. We've greatly expanded since then! 

ORI is a non-profit research institute that does open source research and development for Amateur Radio and beyond. Everything is freely published at no charge. Find out more about ORI at

Address:San Diego, California, United States


7:00 pm gather for social and catered food

7:30 pm program begins

8:00 pm demonstration followed by questions and answers

9:00 pm building closes


Open Research Institute Logo for 2022 ORI logo for 2022 1.22 MiB
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