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FreeDV is a Digital Voice mode for HF radio. You can run FreeDV using a free GUI application for Windows, Linux and OSX that allows any SSB radio to be used for low-bit-rate digital voice.
If you are a hardware or software developer, you can integrate FreeDV into your project using the LGPL-licensed FreeDV API.
FreeDV is being developed by an international team of radio amateurs working together on coding, design, user interface and testing. FreeDV is open source software, released under the GNU Lesser Public License version 2.1. The modems and Codec 2 speech codec used in FreeDV are also open source.
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 FreeDV is comparable to and, in some cases, works better than SSB on low SNR channels.
FreeDV 2020 is built around leading-edge neural net speech coding (LPCNet), putting Ham radio at the forefront of digital radio innovation. It provides 8 kHz wide audio bandwidth while using just 1600 Hz of RF bandwidth.
Urban HF noise is a growing problem for SSB communications. Hams around the world are using the advanced FEC and modem technology in FreeDV to overcome urban HF noise in channels where SSB is unusable.
FreeDV 1600 and 2020 is being used over the QO-100 satellite and for experimental combinations of Internet and HF radio to overcome poor propagation.
If you are a hardware or software developer, you can integrate FreeDV into your project using the LGPL-licensed FreeDV API.
No license fees are required to use FreeDV. Including it in your project is as simple as compiling a library of C code. FreeDV does not require an operating system, it runs happily “bare metal” on small machines such as micro-controllers. It does require a hardware Floating Point Unit (FPU).
The FreeDV stack is gcc compilable C software that runs in about 1% of the CPU resources on a modern PC. FreeDV 1600 and 700D has even been ported to a “bare metal” STM32F4 microcontroller (168MHz, FPU, 128k RAM, 500k flash).
FreeDV requires a floating-point processor. While it might be possible to create a fixed-point implementation, there is little incentive to do so since floating-point processors capable of running FreeDV are now available for under $5.
FreeDV is a high-quality digital voice mode for clear communication over HF radio frequencies. It’s easy to use and accessible to all, eliminating the need for complex equipment or specialized training. FreeDV delivers clear voice with minimal delays under weak signal conditions, perfect for emergency responders, humanitarian aid efforts, and remote workers. It’s also compatible with different radios and interfaces, making it adaptable for any situation.
FreeDV is being maintained and extended by Mooneer Salem K6AQ and David Rowe, VK5DGR. Richard Shaw KF5OIM maintains the Cmake build system and Fedora packaging. Walter, K5WH is leading Windows testing in the USA. Debian packaging thanks to A. Maitland Bottoms (AA4HS) and the Debian Hamradio Maintainers.
As development continues, many people are helping whom we have not credited on this website, but we appreciate all of their work.
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