[FADCA] Re: D-Star Coordination

[Chuck Hast]

On 11/5/06, Paul Toth-NA4AR <ptoth1 at tampabay.rr.com> wrote:
> Chuck...
>
> Thanks for your comments and insight on this important subject.
>
> There were several comments about D-Star at the FRC Board meeting three
> weeks ago (this was prior to the WTB's "store and forward" ruling).  FRC is
> worried about D-Star digital systems being disruptive to the other analog
> repeaters on the frequency.  Then, too, there is the bandwidth issue D-Star
> presents.  D-Star is a narrowband system (6.25 KHz channels) versus most
> analog repeaters (25 KHz).  There is a notable imbalance.  Yes, FRC could
> view D-Star as an opportunity to modernize its coordination policies and
> start moving Amateur Radio toward the same standards the FCC has mandated
> for Land Mobile and Public Safety by 1/1/2013 (Docket 04-292).  But then, I
> like tilting at windmills. :)
>
I am not sure, but being 6.25 it should allow for a 4 channel device on a
25Khz channel, I do not know if it allows for trunking but if it does that would
mean a D-Star would be a very efficient device compared to our legacy
analogue voice repeaters, you would be able to put 4 separate users where
you presently have one... Which is exactly what the likes of NexTel does,
indeed in dispatch mode I think iDEN puts 8 voice channels in a 25Khz
channel, in interconnet mode it goes to either 4 or 6/25Khz channel.
Similar conditions hold for all of the modern trunked digital systems.
If you want higher speeds for data you agregate channels so that you
can move larger amounts of data, and you use interleaving to make it
all work. Your cellphone works in somewhat the same fashion, indeed
most cellphones will do both voice and data if you have the data cable,
but there is not a modem in there, it just injects the computer data into the
data stream with the proper addressing so it will come out where it is
supposed to.

<Flame On>

Funny we in amateur radio who used to be in the forfront
of this stuff are now not even the back side of the dog we are the end of
the tail (pointy end not the end plugged into the dog) and we fight to keep
this legacy junk going.. There are times I just want to quit in frustration,
but there will be people in the FRC who will fight to the death to keep that
old crap out there running. Of course all of that spectrum that they took from
FADCA for those junk 440 repeaters, that was where this sort of activity
should go. But they have it tied up with stuff that puts technical retards to
shame...

I am sorry if I am politically incorrect, but back when they pulled all of the
440 freqs we had for more 440 phone patch and other worthless boxes, we
tried to tell them but no they had to give into the crowd that treads on the
narrrow gray line....

> I have raised the coordination issue because there is a very real chance I
> will need to come to FADCA or FRC in the near future to ask for coordination
> of up to seven (7) D-Star UHF repeaters.  Given the WTB ruling, FADCA seems
> the logical choice, even if D-Star is digital voice.  As you note, it does
> support simultaneous low speed data.  The biggest stumbling block may be
> finding enough available frequency pairs in the UHF band.  D-Star is a full
> duplex technology.
>
We had freqs for this sort of thing but the qualifier is HAD, I think that FRC
has taken most of it for legacy voice junk, I may be wrong but I think that if
you look you will find that most of the old ARRL band plan got hoovered up.

They ought to have to give us back our frequencies but bet that will not happen,
indeed that one is probably seen on the rear end of a deer...

> As for linking D-Star repeaters together, we are looking at the construction
> of a wide band microwave network built on a 3.3 GHz backbone.  The
> technology exists.  It is affordable.  And it is capable of near T3
> throughput at distances of up to 90 km.  That is plenty of bandwidth for
> several VoIP circuits, hgih speed data, even videoconferencing.  This is
> definitely not your Father's Ham Radio!

What is the 3Ghz gear you are looking at?
-- 
Chuck Hast  -- KP4DJT --
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."