[d-star] 1.2G Dstar Voice Just Say OK

[Doug Reed]

Less than half the people on this list are data people. And most of us 
are not too fanatic about it. As far as I'm concerned, the ID-1 is 
mostly a data radio and the fact that it can be used for voice operation 
and connect via digital voice to other users is a great zero-cost 
option. For emergency services work, I tend to think of D-STAR digital 
voice as a back door to the comm room and about as secure as we're going 
to get since we're not allowed to use encryption technology.

As for abusing the list or causing too much traffic, not a chance. 
Everyone on the list signed up to find out what is going on with D-STAR 
in the metro area. Until you started work on your system, there was no 
info to share. Sharing is what the list is for.

I agree with both of you regarding voice repeaters. First, there are way 
more 2M & 440 voice repeaters already available in town than we use on a 
daily basis. How many of them would still be working in an emergency is 
a different question. And no, there is no way I could have a 1.2G 
digital voice module sitting in a box and not be planning to use it. My 
only problem is the cost of the duplexer but I don't mind building so I 
don't have to buy. (Buy is much faster.....)

Regarding the cheap VHF/UHF/SHF splitters, no, they don't have much 
isolation. But all they need to do is reduce the out-of-band signal 
level down to the point that it doesn't over-drive the receiver front 
end. The two main problems are over driving the front-end and harmonic 
generation or intermod in the transmitters.

Ham grade receivers are not too safe from overload but most are able to 
ignore strong signals when they are in another band. The splitter will 
usually provide more isolation than a TX circulator does so the intermod 
in the transmitter is no worse. The splitters even help with harmonic 
rejection because their isolation is added to that of the transmitter. 
I'm using 2M/440 combiners on two repeater sites with no problems.

But I'd still expect a transmitter harmonic to break through no matter 
what you do, simply because the signal level difference is too great. So 
it is even more important than usual to run an intermod frequency test 
program against all transmitters at a site when you are using one of 
these splitters since everything is direct connected.

73, Doug Reed, N0NAS.

Erik Jacobson wrote:
>> Might be a typo here- is D-Star 1.2 voice digital not FM?  It is still
>> useless - you need expensive radios and duplexers to duplicate what we
>> already have a lot of for free.   The high speed simplex data data part is
>> what we need.
> 
> I have to remember who hosts the list -- data people :)  Since this is the
> only collection of d-star folks I know of, I post all my ideas, thoughts,
> and progress here except for things I have to keep in confidence.  I hope
> that's ok with folks - but if I'm abusing the list or causing too much
> traffic, let me know.
> 
> I'm excited to get 1.2ghz voice going too - so I'll proceed, but I understand
> not everybody is interested in that.  It might be just a couple of us
> d-star ID1 owners who use it at first.  That's ok with me - I just want to
> get some neat stuff up and learn about it.
> 
> This project, to me, is more about putting something cool together and seeing
> how it works.  It's been exciting for me so far (with some disruptions of
> frustration :)  I've always been more about providing the service and putting
> it together than being the biggest user of it - from my 1980s BBS sysop days 
> to now :) :)
> 
> Can you honestly have a 1.2GHz repeater DV module sitting in a box without
> putting it on the air?  I don't think so :)
> 
> PS: The cheap splitters don't always have much isolation.  That might be ok,
> and I know some folks are using them.  I don't have personal experience to
> know how much of an affect using a cheap splitter has on operations.
> 
> Erik
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