Hi Guys,
Wow a lot of traffic on the list when I woke up today, that's great to
see :-)
A few months ago I figured we needed to get Codec 2 on the air.
Anthony as you suggest HF Digital voice running on a PC with a SSB
transceiver is the sweet spot for any new DV system.
This requires a HF modem optimised for digital speech, in particular
fast sync (no big training sequences, ability to recover quickly after a
fade). FDMDV was a working system for HF Digital Voice from a few years
ago, so seemed like a good starting point.
One thing led to another and I have ended up writing an open source
versions of the FDMDV modem, based on the FDMDV spec:
http://n1su.com/fdmdv/FDMDV_Docs_Rel_1_4b.pdf.
I am in the final stages of the C version of that modem, currently
writing command line demo programs. I have been working closely with
Mel Whitten from FDMDV on this.
Not sure what the final "system" will look like
(Codec/FEC/protocol/modem) but I wanted to start somewhere. I figure we
need to get some real world HF DV experience to tune and evolve the
system.
Dave Witten is working on a cross platform GUI program to tie the Codec
and Modem together into a user friendly, fully open source Windows/Linux
program, "FDMDV2" if you like.
The cool thing about open source is it attracts the best in the field.
I have been in regular contact with HF modem gurus like Peter Martinez
G3PLX (PSK31), and Rick Muething (WINMOR) who have been very helpful
with suggestions and support as I re-implemented the FDMDV modem. Rick
also has some great ideas for more advanced modulation schemes (trellis
coded PSK) that would be nice to try later. I have also had some great
help from Bill Cowley, who has 25 years of PSK modem experience (and
just happened to be my PhD supervisor and is a newly licensed Ham).
Thanks,
David
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