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HTTP/2 200 x-powered-by: PHP/8.2.29 content-type: text/html; charset=UTF-8 link: ; rel="https://api.w.org/" link: ; rel="alternate"; title="JSON"; type="application/json" link: ; rel=shortlink content-length: 17356 content-encoding: gzip vary: Accept-Encoding date: Tue, 30 Dec 2025 12:50:05 GMT server: LiteSpeed alt-svc: h3=":443"; ma=2592000, h3-29=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q043=":443"; ma=2592000, quic=":443"; ma=2592000; v="43,46" FreeDV | Open Source HF Digital Voice for Amateur Radio

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 macOS 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 6 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).

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.

Who can I Talk To?

Location	Frequency	Description
Worldwide	Any	FreeDV Activity Day Third weekend of every month (0600/0700 UTC Saturday to 0600/0700 UTC Monday depending on US Daylight Saving Time)
Argentina	7.045 MHz LSB	Weekly Hosted by Radio Club Coronel Pringles, listen on the LU4EEC KiwiSDR Saturday 1800 UTC
Australia	7.045 MHz LSB	Weekly Sunday 1030 Eastern Time
UK	3.640 MHz LSB (primary) 3.643 MHz LSB (secondary) 5.3685 MHz USB (after 0930)	RSGB broadcast by Matt G6WPJ Sunday mornings at 0900 Local
UK	5.3685 MHz USB, 3.693 or 3.697 MHz LSB (as conditions permit)	Daily 1600 Local
USA East Coast	7.182 MHz LSB	Weekly Tuesday 2100 EST (Note changed time)

Getting Help

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

Post to the digitalvoice mailing list
Chat tab in FreeDV Reporter (also links to #freedv-reporter channel on Discord)
FreeDV Discord – Useful for chatting or for QSO coordination
Walter K5WH’s Zoom channel (installing Zoom recommended, but not required)
IRC: #freedv on irc.libera.chat port 6697

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

Feature Request

Have an idea for the FreeDV team? Please answer the questions in the FreeDV Feature Request Form, and submit via a GitHub Issue. Note – incomplete or ad-hoc feature requests will not be considered.

Source Code

RADE Source Code
FreeDV GUI Source Code
Codec 2 Source Code
FreeDV GUI Source Code Archive
Codec2 Source Code Archive
Consolidated commit history across all projects, by developer and date

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, and Peter Marks VK3TPM. 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, 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.