Pozdravljeni!
Še vedno čakamo ali bo USCOM uspel dobiti na posojo testni D-STAR RPT od Marcuccija. Repetitor za 70 cm in kontroler sta že v Italiji. Ustavilo se je pri komercialistki Marcuccija, ki vztraja, da USCOM repetitor od njih kupi. Upam na ugodno rešitev, saj nekateri že nestrpno čakamo testiranje.
Prilagam pa še zanimiv prispevek K7VE, skopiran z
http://k7ve.ampr.org/index2.php?option= ... df=1&id=19
D-Star Repeater Audio Linking
(Sunday, 22 July 2007) - Contributed by K7VE - Last Updated (Monday, 20 August 2007)
D-Star Repeater Audio LinkingI wrote this to WY0X in response to a question about using audio based linking between a
D-Star repeater and other repeater platforms. Originally in IllinoisDigitalHam on Yahoo! Groups.
These are applications that people will try but will mostly leave the user base unsatisfied, with a few possible exceptions.
Here is why:
Part of the real power of the D-Star protocol is the radio-to-radio over network addressing.
I set up my radio thusly:
UR CALL: WY0X
RPT1: WA7GIE B
RPT2: WA7GIE G
MY CALL: K7VE
I press PTT and everyone on the input and output frequencies of the WA7GIE 448.725 mHz. repeater can hear me. The
repeater then sees the "G" (Gateway) designation as the next repeater which indicates that the destination radio "WY0X"
is somewhere out on the network. The controller WA7GIE/B passes the packet to the WA7GIE/G gateway computer that
then does a lookup to find what gateway/repeater last heard WY0X. In our use case we'll say that WY0X was last heard
on the KX0XXX/C 2-meter repeater in Denver, so the packet is routed to the KX0XXX/G gateway that then transmits it on
the KX0XXX/C 2-meter frequency where the WY0X radio hears it and decodes the audio "Hello, Nate!" (Along with
displaying any text or GPS information that might be associated on the K7VE radio. Typically the WY0X display would at
least see the strings "K7VE /John" and "http://k7ve.ampr.org" or my email address). Any other D-Star users in the Denver
area would also see and hear the same thing. At this point, WY0X using an IC91AD can press a button that sets up the
return route:
UR CALL: K7VE
RPT1: KX0XXX C
RPT2: KX0XXX G (or is it WA7GIE B ? -- someone correct this if I have it wrong)
MY CALL: WY0X
WY0X now can press PTT and say "Hello, John" and the packets will traverse from WY0X's radio to the KX0XXX/C
repeater through the KX0XXX/G gateway over the Internet to the WA7GIE/G gateway, on to the WA7GIE/B repeater and
finally over the air to K7VE's radio where it will be returned to voice (again with the accompanying text/GPS information
such as "WY0X /Nate"). Also all of the D-Star Users in Salt Lake City will hear and see this conversation.
Simple enough for any D-Star user to collect from this information how to talk to either WY0X or K7VE.
This will be a typical D-Star gateway based QSO. You will note that everything is callsign routed.
Now let's add an audio based gateway/link to an FM repeater in Denver -- this link/gateway is a full time relay of
everything that is repeated on the KX0XXX/C repeater. It is facilitated using a D-Star radio or something built up using
Moe's USB dongle and a soundcard to connect to the co-located FM repeater (Callsign KX0FMX). Now the Denver FM
users are listening to the above exchange. K0RJC is listening and recognizing K7VE's voice (K7VE's ID is in the data
stream so he doesn't need to announce the callsign on voice) as that of his wife's uncle and calls out on FM "K7VE this
is K0RJC", not knowing that K7VE is in Salt Lake City and not on the local repeater at all -- the link radio or software is
smart enough to set up the following for the D-Star system:
UR CALL: CQCQCQ
RPT1: KX0XXX C
RPT2:
MY CALL: KX0FMX
The FM signal would travel from K0RJC to the KX0FMX repeater, thru the link to the KX0XXX/C repeater where it would
show up in Denver, but for lack of callsign routing information would never make the trip back to Salt Lake City and
Richard (K0RJC) would wonder why his wife's uncle was being so rude as to not respond. However, WY0X would hear
K0RJC since the D-Star and FM repeaters are linked. K0RJC has no way to pass back through the D-Star system to
contact K7VE. This would be a very confusing and poor user experience. This is why D-Star repeater operators, who
have already been down this road, discourage these types of links. If you are an isolated D-Star repeater and want to tie
in the local FM crowd this is not so much of an issue, but definitely not a good idea if you have a gateway.
The same scenario exists for P25 and MotoTrbo systems linked at the audio level to a D-Star system. Could be done, not
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a good idea.
Echolink has major issues when it comes to insuring that the operator is actually who he says he is and can enter the RF
realm directly from the Internet, but it and IRLP share the same problems as listed above when connecting to a digital
routed system. If we take the above scenario and add an IRLP node onto the KX0FMX repeater, now you have people
on the IRLP that hear conversations that may or may not have audio callsigns (remember on D-Star the audio ID is
unneeded as the ID is encoded in the data stream) and have no way to know why those operators are not hearing them.
Now with P25 and MotoTrbo, if you can get at the data stream at the repeater (my understanding is that it is often
proprietary and closed), I can envision a smart gateway that would map unit IDs to callsigns that would allow a pseudo DStar
gateway to respond as though those P25 and MotoTrbo radios were D-Star radios and transcode the audio between
the two formats. This would permit D-Star users to initiate calls to P25 users or MotoTrbo users by using callsign routing
through the gateway system. However, the reverse would be impossible without mapping pseudo unit ID in the P25 or
MotoTrbo space to callsigns in the D-Star space -- possible but would require a lot of administration. (Work around
methods are possible using the text messaging for control, but would be less than optimal.)
P25 and MotoTrbo may be excellent for what they were designed for -- providing the infrastructure for a tightly controlled
and geographically contained fleet. However, I think the ad hoc callsign addressing and routing gives D-Star a lot more
flexibility and with the addition of an Open Source gateway and application platform puts a lot more system power into
the hands of hams, especially when it comes to extending the system beyond the local repeater.
I guess I would like to see the model the P25 and MotoTrbo crowd has for a national and international network of
gateways talking to a very mobile user radio base. (e.g. I'm operating in Atlanta and fly to Seattle and without any prior
arrangements with the Seattle P25/MotoTrbo repeater operator be able to operate and have the whole network discover
my radio and route calls for me at my new location, and do it all over again when I get to New Orleans)
One other little kink, even in the local D-Star to local FM/P25/MotoTrbo audio linking scenerio. D-Star has a notion of
callsign squelch. (This has been intriguing to spouses who are licensed but only want to hear the radio when the call is
specifically for them.) The FM/P25/MotoTrbo user has no way to signal that they want the squelch of KC7PAA (K7VE's
better half) to open.
Just some food for thought.
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