Re: Codec2

"David Lake (dlake)" <dlake@...>
 

So the main benefit of TDMA is being able to double repeater capacity in one RF slot. That's one antenna, one duplexer, one site rental. Certainly in the UK where we pay commercial rates for tower access and there is no free spectrum, it's a big deal.

David

Sent from my iPhone

On 23 May 2012, at 04:20, "Tony Langdon, VK3JED" <@vk3jed> wrote:

At 09:37 AM 5/23/2012, you wrote:


CODEC 2 is currently missing any FEC, and will
not operate down at the required bit-rate to be
usable in D-Star. It’s getting there, but I
think it has a way to go so don’t expect a swap-out any time soon.
In time, I'm sure Codec2 will get there.


Now, the Yaesu offer (currently) is a dPMR-based
FDMA system.  But it does look like they will
be going to a DMR TDMA system in the future.
I'm not sold on TDMA myself. That comes from
living in a land known for its wide open spaces,
and a past history of working VHF/UHF
openings. What are the timing (and effective range limitations) of DMR TDMA?


dPMR and DMR both use AMBE2+ - not compatible
directly with AMBE2 in D-Star, but DVSI have
(very cheap) chips that can do both modes. And
of course you can transcode between them, either
in software if someone is willing to pay DVSI
$,000s for the SDK, or in hardware if $20 is more in your budget.

So, what we need (as I proposed at Dayton) is an
Open Amateur Trunking protocol that can
transport all these different codecs, and then
allow people to transcode between them.
Agree totally. It would be nice to be able to
say "I want to communicate with..." and let the
network figure out what network and mode that
destination is on, and how the two should be
connected (callsign route? link? via a
reflector or transcoding conference server?).


Yes, you will be locked into D-Star for a while,
but I don’t see why that should be a barrier
to talking to someone on, say, a DMR-based system.Â
From my experience with EchoIRLP, if you find a
way to make the different systems accessible to
end users in a single place, in a convenient way, they'll love you for it. :)

The "internetworking protocol" (not to be
confused with IP ;) ) should be open, flexible
and extensible. Almost the subject of a group in its own right! :)

73 de VK3JED / VK3IRL
http://vkradio.com



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