On 11 May 2012 19:27, Bruce Perens <br...@perens.com> wrote:
> On 05/11/2012 11:06 AM, Peter wrote:
>
>
> No matter how little bandwidth we use on VHF/UHF, it's likely we'll be
> occupying a whole 12.5khz channel anyway due to the way FM radios are
> designed (assuming home brew addon kit here).
>
> I think you should assume that our major deployment on VHF/UHF would be a
> manufactured-for-purpose radio, rather than a homebrew dongle on an
> existing HT.
>
> If you are only proposing this D-STAR variant for *experimental* use, go
> on as you are, but be aware that it would probably be succeeded by a
> different implementation in purpose-built equipment.
>
> We have the potential, in a purpose-built radio, to offer:
>
> - *Really* narrow-band channels, like 2 KHz. This will be welcomed in
> places like California where we have lost much of our 440 repeater
> operation to PAVE PAWS and thus need more channels on other bands.
> - Proportionally better range for the input power, which is very
> important to users.
>
> Thanks
>
> Bruce
>
For some reason this went to you and not the list. I think because you CC'd
the original to me direct as well as the list. Anyway shifting it back to
the list.
I think mainly I was looking at homebrew + hardware to be added onto radios
(external kits) or modified into the radio. DVRPTR style for example.
So many times I hear people complain that the experimentation/home brew
aspect from amateur radio is being diminished. Indeed it's my own personal
pet peeve with D-star, that the codec is closed and you need to buy a chip
just to use it. So it's for this reason that I see codec2 as a good way to
resolve that, in the digital age. I don't really have the know-how to
design a modem from scratch, for sure I don't have the time. My programming
experience is a mile away from this. I do know how d-star works and I know
the caveats for implementing a VHF DV system. There's also an overlap with
my real world programming experience which is from a design perspective and
also that essentially designing a lean data protocol with real time demands
really is quite similar to some of the EDI projects I've been involved
with. I'm also fairly confident all the building blocks to make this work
already exist and just need a protocol, and then be brought together.
In any case, I think that projects using standard FM channel bandwidths and
those using lower bandwidths can peacefully co-exist (they're not
performing the same task). It's when we start making competing standards
for the same purpose, things get a bit confusing for everyone. In fact, the
FDMDV will work fine on SSB on VHF/UHF too. In fact, I am tempted to get
some of my club members involved in this regard at the very least. Quite a
few that are into digital modes in general. But that's another story.
Best regards,
Peter.
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