On Mar 12, 2009, at 9:47 PM, Woodrick, Ed wrote:

> There are two ways to talk to another repeater, the first, the one  
> supported by the Icom software allows you to program a repeater or  
> user into the UR field and your packets get routed to the distant  
> repeater. If anyone wants to respond to you, they have to program  
> their radios to talk back to you. You can't listen to the distant  
> repeater and there is no such thing as linking and unlinking. If  
> someone is talking on the distant repeater, you interfere with them.
>

All they have to do to "program" their rig to talk back, is to hit the  
one-touch button... all the rigs other than the commercial HT's,  
turned D-STAR by dropping in a board... have that feature.  It's easy  
as cake to do... push and hold while they're talking, and their  
appropriate callsign routing information is temporarily (until you  
switch memory channels or change it) copied into the memory of your  
rig.  Works almost flawlessly.

Callsign routing also has the excellent additional benefit in that it  
will "follow" anyone anywhere in the network, as long as they've keyed  
down ONCE on the local repeater... wherever they may roam.   If you  
put "WY0X" into your rig, and I go to California, Hawaii, or even just  
switch modules on our local repeater stack... your call will find  
me... as long as I've keyed once.

> The method that is becoming more common is to link the repeaters.  
> This is done with the DPLUS software which most every repeater that  
> is connected with gateways are running (except Japan). With link,  
> you program your radio to link the repeaters, key down and then  
> switch back to the normal programming. At this point the two  
> repeaters are linked together, If someone keys down on one, it is  
> heard on the other. No special programming is required for users.  
> Matter of fact it is often hard to tell that you might be talking to  
> someone across the world (except for their accent). When you are  
> finished talking, you then unlink the repeaters. This is very  
> analogous to repeater linking in the FM world, or IRLP.
>

This kinda "dumbs down" D-STAR... and while I see it as a positive  
thing, you also completely lose the feature that's built into the  
callsign routing -- a CONFIRMATION at each unkey that your  
transmission made it to the other side.  There's other minor nitpicks  
in the implementation I would mention also, like if you link in and  
someone's talking -- the current version of dPlus doesn't immediately  
start streaming the conversation -- it only starts after the next  
unkey.  This leads to doubling and confusion, since folks think it  
really is "just like" IRLP or Echolink where once the VoIP path is  
established, if the far end is talking -- you hear it.

D-Plus linking does NOT work that way, and the only SUREFIRE way to  
make sure you're not barging in on a conversation is to link and then  
WAIT at least the full repeater timeout time-constant, of 3 minutes  
before transmitting.  If someone's long-winded in an on-going  
conversation (guilty as charged!) you may not hear anything until they  
turn it over to the next person, 3 minutes hence.

> To help with determining how to program your radio for the specific  
> function that you want to do, head to the D-STAR Calculator at 
> http://www.dstarinfo.com/Calculator/ 
>  and just select where you are and where you want to talk to, it  
> hopefully dramatically simplifies the entire process.
>

Works for callsign routing too.

Just being an advocate for the system "as-designed"... too many folks  
never experience D-STAR as it was designed and meant to be used,  
because they're always D-Plus linked somewhere.  Japan hasn't ever had  
D-Plus linking, and they communicate all over the country on their  
system without it, just fine...

Just something to gnaw on in your head... I tend not to say that D- 
Plus linking is "the future" of D-STAR... it's just the implementation  
of what we "used to have" for linking large numbers of repeaters in  
the old FM world... great for generating traffic and "noise" on a  
quiet/dead local repeater, but if you're not looking for a general  
QSO, and you're looking for an INDIVIDUAL... D-STAR *excels* at that.   
I highly recommend folks give it a try... it's fun.

It's also not hard at ALL to have a roundtable between multiple  
stations using callsign routing.  We've done it before... Station A  
and B are talking via callsign routing, Station C pops up on the local  
repeater where Station A is at.  If Station B hits their one-touch  
button when the remote end (Station B) is talking, now they're all set  
to both be heard locally (that always works), and be heard on the far  
end by Station B.  All stations involved can hear and be heard and can  
have a round-table conversation.  Works fine.

I think a lot of people don't think about that... they think it's  
always a "one-to-one" relationship... I'm calling Bob.  No one else  
can participate.  But it's EASY for another person to join in with  
callsign routing, if they think about it a little bit.

And ALL stations in that conversation get a real CONFIRMATION that the  
remote repeater HEARD what they transmitted.  If someone "doubles"...  
they're going to be able to tell because they'll get "RPT?" back  
instead of "UR?" on their rig when they unkey.  The Reflectors simply  
don't have this capability, and it shows during Nets if the Net  
controller calls for general checkins... some calls get in, others go  
to the bit-bucket and have to be repeated.  It's not as clean as the  
callsign routed design.

The "fix" Icom put in for large groups of repeaters is the Multicast  
route.  This requires some pre-setup by the Gateway operators, but  
also works well, from what I've heard.

When you start to MIX D-Plus linking and callsign routing, it really  
gets ugly though.  You callsign route into a repeater module that's  
already linked somewhere, and get "carried" to the Reflector or linked  
repeater, but the people there can't reply.  That gets messy fast.

Nate WY0X

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