A couple of days ago, Bruce, K6BP, tweeted:FreeDV radio digital voice 1.3 released as source, no packages yet. 700D mode reported to consistently outperform SSB, is loud and clear while SSB is inaudible, error-free transatlantic communication reported.
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. There are several reports of the new FreeDV 700D mode outperforming SSB at low SNRs. At high SNRs FreeDV 1600 sounds like FM, with no annoying analog HF radio noise.
Alternatively you can buy a SM1000 FreeDV adaptor that allows you to run FreeDV (1600 mode) on any HF radio without a PC or sound card. If you are a hardware or software developer, you can integrate FreeDV into your project using the LGPL licensed FreeDV API.
Speech is compressed down to 700-1600 bit/s then modulated onto a 1.25 kHz wide signal comprised of 16 QPSK carriers which is sent to the Mic input of a SSB radio. The signal is received by an SSB radio, then demodulated and decoded by FreeDV.
FreeDV was built 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 Public License version 2.1. The modems and Codec 2 speech codec used in FreeDV are also open source.
It would be interesting to see if freedv could be incorporated in some of the modern SDR transceivers, such as the Icom IC7300. If so, would likely spark more interest in HF DV modes, and give a compelling reason to upgrade your rig.
I was going to mention that, but it slipped my mind. I wonder how difficult it would be for the manufacturers to do that. Elecraft can modulate and demodulate PSK31 and RTTY, so perhaps they’ll give it a shot.
It’s already been implemented in some of the Flex radios. I think the limitation in the Elecraft radios is that there isn’t enough horsepower in the DSP chain to do something as complex as voice codex. The Flex radios either use your computer to do the heavy lifting, or have high-end processors built in (for a price, of course).
I saw Bruce’s demo at Hamvention. It was pretty impressive, as far as S/N and naturalness of voice was concerned.
I’ve listened to the older stuff on 20 meters, but never engaged in a QSO. At the time (and it is still likely) you either needed the Rowetel box or a 2nd sound card to transceive. I got a cheap USB sound dongle, but never went to the trouble to set it up with a headset, etc.
Elecraft, of course, may surprise us. They certainly have in the past.
Exciting. Bring it on.
Looks really interesting, can’t wait to try it.
I don’t believe it will unless a better program is developed other than free DV have tried it and don’t like the water fall design or the processed voice sounds to hairy to me.It’s a step in the right direction but better program design is needed.The program has very little eye appeal and is to small and to wimpy is design.As far as I know this is the only HF digital voice program out there on HF.I’m surprised there isn’t more
Too much “robot voice”? The same (sort of) thing was said of SSB in the very early days. Sure you could zero-beat for a while but eventually, VFO drift would kick in and your roundtable members would begin sounding like helium-breath … the thing that makes amateur radio so great, in my humble – is hams’ dogged tenacity … So a giant hat-tip to the FreeDV development team for demonstrating that tenacity … and it’s only getting better. The task of getting refined-sounding voice quality from the bit rates and bandwidth they’re working with is monumental … and yet astonishing progress is being made. Kudos!
I have it in my Flex but I have never heard anybody using it.
You are going to hear it all kinds of ham satellites, soon.
Taurus-1 just launched from China.
FM up, Codec2 down.
Already seen some DV streams on the QO-100 European and Qatari ham band GEO satellite transponder via the Goonhilly Web SDR.
As an IT guy who sends behind a keyboard a lot already, I prefer phone/voice modes on the radio so having a digital phone mode that works below at noise levels where SSB won’t is great. The fact that they’re making devices that can do so you don’t have to use a computer is great. The fact that everything is open source means adoption will likely be a lot higher. I have an Icom IC-7100 which will do D-Star on HF, but I don’t hear much of it out there.
looks like that this will have FreeDV:
https://www.retevis.com/Ailunce-HS2-HF-VHF-UHF-SDR-Transceiver/?fbclid=IwAR3jmmM4oxiO383IWOxwXlp3Sn5aXNRttgAnvtIYeno4iJsdfCZfz23xjkg
Very interested in trying out C4FM (ft991a) on HF ((other than 10m))