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Author Topic: Dstar and Emcomms  (Read 18235 times)
KC8AHN
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Posts: 108




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« on: January 01, 2011, 10:09:55 AM »

I am reading more and more about Dstar being brought in for emcomms and that in some places this is now the standard. (ok,so this info comes from Dstar interest sites and fourms). I am curiuous what others on this board thought. I ask because I am thinking of buying a Dstar radio for use, but also a DVAP so that I can access the network from nearly anywhere.

Just looking for general thoughts.
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K1CJS
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« Reply #1 on: January 01, 2011, 11:32:28 AM »

Some areas--few right now, are embracing D-star, but most of the articles around are hype to try to get D-star deployed in more areas.  To tell the truth, it is NOT the standard and probably never will be.  It's an improvement in some ways such as clarity, but it is not as good as regular FM transmission/reception.  In fringe area reception, weak signals can cause reception loss of some of the information transmitted.

Until clarity and fringe reception problems can be rectified, it is just another attempt at something new and modern that works well--up to a point.  Beyond that point it fails badly, even worse than regular FM communications.
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KC8IUR
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« Reply #2 on: January 05, 2011, 11:06:15 AM »

The ID-1 provides the easiest (and best) solution for networking over the air. Other than extended LANs, I don't see much point.
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WB6DGN
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« Reply #3 on: January 05, 2011, 08:36:16 PM »

D Star is one of three digital systems that hams are experimenting with to varying extent depending on area.  While D Star is the only "ham" system, hams are also using P25, the de facto public safety standard as well as a somewhat newcomer, known in the US as Mototrbo, a TDMA based system.  All have their advantages and, of course, disadvantages, but, as I understand it, Mototrbo is the only "open" system which doesn't involve an expensive, proprietary VOCODER; meaning that that system has the best chance, so far, of prices dropping into the ham-affordable range the soonest of the three.  Pricing is also the biggest downfall of P25 systems as a used P25 radio would be closer in price to a new D Star offering though that, in itself, is not the full story.  I suggest that you search on the three primary systems; there is a lot of information, both technical and utilitarian, on the web and, I think, it makes interesting reading.  Hope this helps.
Tom DGN
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K5LXP
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« Reply #4 on: January 06, 2011, 11:38:31 AM »

DStar is a solution waiting for the right problem to come along.

In summary, it excludes a number of the already limited number of hams that would otherwise partipate in emcomm but can't or won't due to the cost.  It decreases reliability because the infrastructure is more complex and for the most part relies on the internet.

Nothing against the mode.  As a VOIP toy it's great but it's real capabilities are far oversold, often at taxpayer expense in the form of emcomm grants.  This stuff has been on the market for what, 10 years now or more?  Compare that rate of adoption vs something like packet, or PSK31.

I suspect that at the rate commercial and industrial communications solutions are evolving, DStar (and Winlink) will soon be relegated as a footnote in amateur radio history.  It will either get rolled up into another (more useful) protocol or replaced entirely.  The sooner ham radio gets out of the public safety business, the better.


Mark K5LXP
Albuquerque, NM
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AA4PB
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« Reply #5 on: January 06, 2011, 11:53:23 AM »

Keep in mind that a DSTAR radio will also operate traditional analog FM. How much use the DSTAR mode will get depends on the local activity.
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KC8IUR
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« Reply #6 on: January 06, 2011, 12:32:37 PM »

I'd like to add that I would like the idea of D-STAR much more if it wasn't tied to one manufacturer of radios. I have used the "military only" Harris SDRs that pimp ALE and full digital audio. They're amazing, but D-STAR isn't even close.

D-STAR does do what a lot of discrete amateur technologies do and it combines them all into one neat radio package. Make D-STAR open source or at least a licensed technology and it would be a must have.
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AA4PB
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« Reply #7 on: January 06, 2011, 12:57:09 PM »

Unfortunately, all of the mature voice codecs are propriatary so Icom must license their use (drives up the cost) and is not permitted to release it to other mfgs. Overall, that probably is slowing down the progress of amateur radio digital voice technology.
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KC9GMX
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« Reply #8 on: January 06, 2011, 07:43:27 PM »

lets do some basic math...

D-star dual band mobile with gps option about $800. This one radio can then do packet type of communications, APRS type, small file transfer, and of course, voice. But wait there's more. It can do all that on one channel, you don't have to change frequencies back and forth.


To do all that with "old" ham technology.
You would need 1- 2m mobile to run APRS, 1- 2m mobile to run packet, 1-2m radio for a winlink set up for email/ file transfer (at a slower trasnfer rate than with d-star), and a dual band mobile for voice. Good luck not getting desence from the 4 radios you have all trying to transmit on 2m at the same time. Oh, and the cost...
Thats $700 just for the radios, and then you need the interfaces and tncs, and 4 antennas instead of 2.

So, if you group only needs 1 of those technologies, then thats fine. But if you think you need all of them, might as well go with d-star.
The repeater only relies on the internet when you are trying to communicate from one repeater to another. But using it just like a single site 2m fm repeater, a repeater is a repeater.

Dont try to think of d-star as any kind of replacement for HF. D-star is meant for local emergency communications in times of disaster.

Steven KC9GMX
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K4CJX
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« Reply #9 on: January 09, 2011, 10:10:25 AM »

D-Star requires a local communications infrastructure as does Public Safety interoperability and Mutual Aide.  When one goes, they ALL go. Thus, the trick is to provide some methodology that does NOT require a local communications infrastructure.  This, of course, is an advantage provided through Amateur radio, especially for WX related casualty events that tear things up or burn or freeze municipal tower site installations.

IMHO,


Steve, k4cjx, aaa9ac
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KG4RUL
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« Reply #10 on: January 09, 2011, 11:41:43 AM »

D-STAR

A solution still looking for a problem!
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KC9GMX
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Posts: 40




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« Reply #11 on: January 14, 2011, 09:31:36 AM »

D-Star requires a local communications infrastructure as does Public Safety interoperability and Mutual Aide.  When one goes, they ALL go. Thus, the trick is to provide some methodology that does NOT require a local communications infrastructure.  This, of course, is an advantage provided through Amateur radio, especially for WX related casualty events that tear things up or burn or freeze municipal tower site installations.

IMHO,


Steve, k4cjx, aaa9ac


So a few months ago when my ARES group did a demo for our county EMA using d-star to send a pretend supply list in MS Excel format from a mock shelter to the EOC 18 miles away, without any infastructure was my imagination?

You should use D-star before you assume you know what your talking about.
Just like FM 2 meter, you can use dstar in simplex.
So after a disaster and ALL repeaters go down, ARES here can still set up a quick data network using simplex 2 meter frequencies on D-Star.
I dont think HF would have been the best choice to move this type of information 18miles over mostly flat terrain, and I dont know if there is an easy plug and play method to do this with standard FM analog 2 meter.
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AI8P
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Posts: 118




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« Reply #12 on: January 14, 2011, 09:45:20 AM »

You certainly don't need 4 radios to do what DSTAR does!   What nonsense.

I can run my Yaesu 8800.  I can run 1 side for voice 440.  On the other side I have 2M packet using a $20 TNC.  Using AGWPE,  I can let APRS,  Winlink and Packet all access 2M.   They can all peacefully co-exist.

Your exaggerations diminish your credibility.

Dennis
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W3JKS
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« Reply #13 on: January 14, 2011, 01:31:14 PM »

That whole "the codec is too costly" is simply NOT true.  I can buy one AMBE codec chip from a ham in the Netherlands, quantity one, for 25 Euros!  Don't believe me  -- look on www.dutch-star.eu.

There may be reasons why you don't like Icom, but the cost of the codec isn't factual.  Even if you are using Bruce Peren's new, real-soon-now, "free" codec, it has to run on something physical and it won't be free.

Look it up.

73,
john W3JKS/AAT3BF/AAM3EDE/AAM3RE/AAA9SL

PS.  I am building an Icom-free UHF D-Star repeater right now.  Open source software, Fred's "Dutch" S-Star board, pair of "old" Motorola GM300 radios and a duplexer.  It's not off-the-shelf, and its a lot of work, but infinitely more interesting than buying an Icom repeater at HRO.  Grin
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K1CJS
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« Reply #14 on: January 14, 2011, 04:46:17 PM »

Right now it's still a more expensive 'toy' that doesn't offer any advantages over conventional FM.
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