Embedded

From: [email protected] [mailto:[email protected]] On 
Behalf Of Nate Duehr
Sent: Friday, March 13, 2009 12:37 AM
To: [email protected]
Subject: Re: [DSTAR_DIGITAL] D-Star to "listen" to reflectors or distant 
repeaters


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.


Not all the D-STAR radios have the one-touch button and on the mobiles, it is 
far from being one-touch, more like four or five touches. Not at all easy to do 
when you are supposed to be driving.

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.

Doesn't really work that well. Once you get a number of repeaters in an area, 
you'll find that it really doesn't follow you much at all if you are driving 
between repeaters, yes, if you fly across country, it will follow you, at least 
they can find you a couple of hours after you first key down.

> 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.

Yes, it doesn't start immediately. But at least you CAN wait three minutes for 
conversations to stop and then start talking. The native routing NEVER gives 
you the ability to hear what is happening on the remote repeater.


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...


Yep, not many people experience 1.2 GHz voice and high speed data. You did say 
"as designed" didn't you? Remember, that 2M and 440 D-STAR is a rarity in Japan 
where the system was designed. And don't think that the routing that is in the 
Icom implementation is necessarily the way D-STAR was designed, that's the way 
Icom implemented it. It would be quite consistent with the design if when you 
programmed your radio for legacy routing that the repeaters actually linked 
their selves first.

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.


No, it isn't a "used to have" it's a "required to have" functionality. The 
Southeast Weather Net is a good example of that. You can't have a net with the 
legacy routing and more than 2 repeaters. And if you try to do it with the 
broadcast functionality in G2, that just doesn't work well unless everyone were 
to get DS3 connections.

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.


That ONLY works between two repeater modules. And as an example of how your 
"ease of use" isn't, take this example. Station A on repeater 1 is talking to 
Station B on repeater 2. Station C on repeater 1 hears the conversation and 
wants to join in. Now, if they can't take the time to study their display and 
then look at the detail routing, they can't tell where A or B is at. But, what 
they hear is a conversation on the repeater, so they just respond with their 
normal programming. The guys tell him that he needs to use the one-touch (he's 
got a 2820, so it's a couple of touches and rotates) and when the guy next 
talks, he does his thing. He then replies and the remote guy doesn't hear him. 
Whoops, he one touched the wrong guy. He does it again and it still doesn't 
work. Evidently this time he got a bad decode at the beginning of the remote 
transmission and the routing didn't make it through.

After 10 minutes of screwing with it and busting up a conversation, they decide 
to all sign.

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.

ONLY if you are looking at your display. Most of the time I try to look at the 
road.


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.

You've heard wrong. When Robin put together the first world-wide multicast net, 
the problems became quickly evident. For repeaters on DSL circuits, they can't 
handle a multi-cast of over a few stations. And the users have to program this, 
they can't use the one-touch.


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.


I'll give you a great example of how well callsign routing can work. It the 
Dayton hamfest last year, the local repeater didn't have D-Plus. All remote 
conversations had to occur with callsign linking. There were a couple of QSOs 
during the weekend, but the majority of the time there were many stations 
callsign routing into the repeater and busting up QSOs. The on-site folks 
stopped using the repeater because you really couldn't carry on a conversation 
without someone callsign routing into the middle of it and calling CQ.

And the most important part is that new users understand linking a lot better 
than callsign routing. I've watched a number of presenters try to explain 
callsign routing to new users and I just see the new user's eyes glaze over. To 
explain linking is much easier. Switch to the channel that you have set to 
link, push the PTT, wait for the repeater to indicate that it has linked, 
switch back to the normal channel and wait a few minutes to see if anyone is 
talking. Call your station or CQ. When finished, switch to the memory channel 
for unlinking, push the PTT and listen for the unlink command. That's it. No 
other user has to do anything.



Japan's Amateur Radio operations are evidently quite different than those in 
the US and other countries. From what I've heard and seen, handhelds are rare, 
operators seldom have two radios. Net operations don't really exist. I guess 
they operate VHF/UHF much more like HF, one to one QSOs.





Nate WY0X



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