Introduction

FreeDV is a suite of digital voice modes for HF radio. Our flagship mode is the Radio Autoencoder (RADE). You can run RADE using a free GUI application for Windows, Linux and OSX that allows any SSB radio to be used for high quality digital voice.

FreeDV technology is being developed by an international team of radio amateurs working together on Machine Learning, DSP, coding, design, user interface and testing. The project is managed by a 5 person Project Leadership Team (PLT). Current development is being generously funded by an ADRC grant and our Financial Sponsor is the Software Freedom Conservancy. All software is open source, released under the (a) GNU Lesser Public License version 2.1 (GUI and legacy FreeDV modes) and two-clause BSD license (RADE).

News

Check the GitHub Releases Page for the latest information on software releases.

Why FreeDV?

Amateur Radio is transitioning from analog to digital, much as it transitioned from AM to SSB in the 1950s and 1960s. How would you feel if one or two companies owned the patents for SSB, then forced you to use their technology, made it illegal to experiment with or even understand the technology, and insisted you stay locked to it for the next 100 years? That’s exactly what was happening with digital voice. But now, hams are in control of their technology again!

FreeDV is unique as it uses 100% Open Source Software, including the speech codec. No secrets, nothing proprietary! FreeDV represents a path for 21st-century Amateur Radio where Hams are free to experiment and innovate rather than a future locked into a single manufacturer’s closed technology.

Controlled testing suggests our flagship RADE technology compares favorably to SSB on high and low SNR channels.

Here is what you need

  • An SSB receiver or transceiver
  • Either:
    • FreeDV GUI software (download links are below, available for Linux, macOS and Windows),
    • An ezDV Digital Voice Adapter (note – does not support RADE).

Connecting Your Radio

If you don’t have a built-in sound card for digital modes you can use the normal audio inputs and outputs of your radio. The same cables and hardware that you use for other digital modes that are based on PC programs will work with FreeDV, but you will need a second sound interface for the microphone and speaker connections to the FreeDV program. A USB headset of the sort used by gamers is all you need for the second sound interface.

Download

Getting Help

If you need assistance with FreeDV, you can try the following:

Documentation

  • Radio Autoencoder (RADE)
  • FreeDV GUI User Manual in HTML or PDF – How to get started, notes on advanced and new features in the latest versions of FreeDV
  • FreeDV Technology – An overview of the technology inside the legacy FreeDV digital modes
  • ezDV – Our latest hardware device for FreeDV with Wi-Fi support
  • Codec2 (overview and deep dive)
  • SM1000 Manual – How to set up, use and re-flash the SM1000

Who can I Talk To?

Login to FreeDV Reporter (source) to find other Hams using FreeDV.

Source Code

Credits

The FreeDV GUI program is being maintained and extended by Mooneer Salem K6AQ. David Rowe, VK5DGR, leads the signal processing aspects of the project (Radio Autoencoder, Codec 2 speech codec, modems, RADE and FreeDV waveforms). See also the Radio Autoencoder Credits.

The FreeDV Project is managed by the Project Leadership Team (PLT): David Rowe VK5DGR, Mooneer Salem K6AQ, Walter Holmes K5WH, Mel Whitten K0PFX, Brian Morrison G8SEZ. Our financial sponsor is the Software Freedom Conservancy.

Current development is being generously funded by an ADRC grant.

As development continues, many people are helping whom we have not credited on this website, but we appreciate all of their work.

History

In 2012 the FreeDV GUI application was coded from scratch by David Witten (GUI, architecture) and David Rowe (Codec 2, modem implementation, integration).

The FreeDV GUI design and user interface is based on FDMDV, which was developed by Francesco Lanza, HB9TLK. Francesco received advice on modem design from Peter Martinez G3PLX, who also advised David on the FDMDV modem used in FreeDV 1600.

Mel Whitten, K0PFX has contributed greatly to the design, testing and promotion of several Digital Voice systems, including FDMDV. This practical experience has led to the current design – a fast sync, no FEC, low latency system that gives a “SSB” type feel for operators. Mel and a team of alpha testers (Gerry, N4DVR; Jim, K3DCC; Rick, WA6NUT; Tony, K2MO) provided feedback on the usability and design of FreeDV.

Bruce Perens has been a thought leader on open-source, patent-free voice codecs for Amateur Radio. He has inspired, promoted and encouraged the development of Codec 2 and FreeDV.