Hi David, I'm actually only able to do SSB on 2 meters at the moment (and only with one radio). Once things calm down, perhaps a radio that can also do 70cm SSB would be useful to have. In the meantime, I figure I can get a cable made up to let me use VOX with a HT and at least hear myself transmit; I need to anyway so I can figure out an inexpensive way for people in the local ARES group to use Winlink and other packet radio resources without needing to invest in something like a Signalink.
As for the SM2000, it might be useful to resurrect at some point. Or perhaps include the lessons learned in a future project. :) Thanks, -Mooneer On Tue, Mar 31, 2020 at 11:15 PM David Rowe <[email protected]> wrote: > > > Nice! This kinda makes me want to try FreeDV on VHF/UHF now (even if > > just with 2400B to start). It might even be easier to get people to > > adopt it around here if they don't need to set up a HF station in their > > small to nonexistent back yard :) > > You cna also try the OFDM modes if youhe a SSB radio. > > > BTW, I wonder what happened with the SM2000 > > (http://www.rowetel.com/?p=4694). > > Brady and I managed to get about half of it working then life got in the > way and we moved onto other projects. > > Cheers, > David > > > > > -Mooneer K6AQ > > > > On Tue, Mar 31, 2020 at 1:56 PM Jeroen Vreeken <[email protected] > > <mailto:[email protected]>> wrote: > > > > Hi all, > > > > During the last few weeks I had some more time available than > > expected (working from home for obvious reasons) and finally got > > around to do an experiment I wanted to do for a while now: implement > > and test a new mode for use on VHF/UHF. > > I really liked the idea of mode 2400B, but it is relativly wastfull > > with bandwidth, and I also wanted to have a bit higher quality > > codec2 mode so it can actually compete with analog FM. > > So I tried something different: a 6000baud mode with raised cosine > > symbols. > > A zero is encoded as an inversion, ones as a continuous level. > > To prevent to much DC in the signal after each 9 bits a zero is > > inserted. > > > > Originally I wanted to use a higher bitrate LPCNet mode, but > > couldn't figure out how to set it to anything other than 1733bps > > yet. So for the time being I am using mode 3200, but can still swap > > it out later as there is 4666bps available. > > I used a frame length of 120ms, partially to reduce overhead, but > > also to make it easier to switch to another codec later, 120ms can > > handle all the current codec sizes: 20ms, 30ms, 40ms etc... > > > > In order to make each identification more standardised and to always > > have a data channel available each frame has data. > > Either 64bits in case of a voice frame, or 608 in case of a full > > data frame. > > > > Yesterday I did some on-air tests between my home and our local 70cm > > repeater (the discriminator output is connected to the controller > > and can be sampled directly). At home I used the packet input of my > > ft-817. Using 5W this resulted in a near perfect (might need some > > finetuning) signal over a distance of 11km. > > > > My current status can be found at > > https://github.com/JeroenVreeken/codec2 in the m6000 branch. Be > > aware that I have not extensively tested with real audio data yet, > > my tests were with artificial voice data to be able to test easily. > > Next step is to use the new lib for the actual repeater. It is > > currently configured to receive both analog FM and mode 2400B, but > > it should not be hard to switch 2400B out for 6000. Just need to > > check that the correct amount of samples is used everywhere. That > > should enable some real world tests. > > > > 73s, > > Jeroen > > > > > > p.s. some values from the README: > > | second | frame > > ----------------|---------|------ > > baud | 6000 | 720 > > inserted 0s | 600 | 72 > > sync bits | 133.33 | 16 > > --------------------------------- > > voice bits | 4666.67 | 560 > > used voice bits | 3200 | 384 > > codec2 frames | 50 | 6 > > extra data bits | 533.33 | 64 > > control bits | 50 | 6 > > reserved bits | 16.67 | 2 > > --------------------------------- > > data frame bits | 5066.67 | 608 > > control bits | 83.33 | 10 > > reserved bits | | 14 > > > > > > _______________________________________________ > > Freetel-codec2 mailing list > > [email protected] > > <mailto:[email protected]> > > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > > > > > > > _______________________________________________ > > Freetel-codec2 mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > > > > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >
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