Response threaded in the questions:

At 01:21 PM 3/22/2009, you wrote:

>I've been trying to understand the usage of the UR field. I understand 
>that it's where you put the destination call sign. But it's usage is a 
>little vague and confusing.
>
>For instance.
>
>1) I have made calls locally, without changing from the default CQCQCQ. 
>When it putting something there mandatory, to complete a call?

There are a variety of situations where you need something specific in the 
UR field.  For local repeater operation, or for DPLUS "linked" repeater 
operation, CQCQCQ is all you need.

To route your signal to a distant repeater (the original method of D-STAR 
networking), you put the distant repeater's callsign and port letter in the 
UR field, preceded by a / (the / says it's a repeater). A six-character 
callsign, preceded by the slash and followed by the port letter, will fill 
the 8 character field.

To route your signal to a specific D-STAR, no matter where they are, enter 
their call sign (no slash, no port letter). The D-STAR network maintains a 
list of everyone who's keyed up a Gateway-connected D-STAR repeater, and 
will route your signal to the last repeater that person keyed up in the 
past few weeks. (of course, it has no way to know if that person is still 
listening).

There's more. ICOM's radios have a form of selective calling based on call 
signs. If you put your radio in "DSQL", it will remain silent to all 
signals unless they have your call sign in their YOUR (UR) field. This 
works locally on repeaters and simplex, and over the network. A call routed 
over the network to you because it has your call sign in its UR field will 
open your "DSQL" receiver.

>2) And, there are times when a "/" is required in front of a repeater call 
>sign. When is the "/" mandatory and when it is not?

The / tells the system you're routing to a repeater, not an individual. So 
it's mandatory to reach a repeater using the "original" routing scheme. I 
think the DPLUS linking scheme, discussed below, is becoming more popular, 
the routing scheme still works and has some advantages.

>3) And, is the module number necessary, in the UR field?

Yes, when routing to a repeater. Many D-STAR systems have all three voice 
modules (2m, 70 cm, 23 cm) under the same call sign. The module number 
tells them which repeater you want to key up (A=23cm, B=70cm, C=2m).

>4) And, there are only 8 character field to deal with and some callsigns 
>and port take all 8, if you count a slash. Are there any combinations that 
>exceed 8 characters?

No. 8 is the limit of the system, so nothing can use more.

>5) Say I was monitoring the D-Stars user list. And say I saw someone in 
>San Diego, using KI6KQU B. If I want to make a call to that person, in say 
>San Diego, would I put their callsign in the UR field or would I put the 
>repeater callsign? OR could I use either? If I used the repeater, would I 
>prefix it with a "/" or would I leave out the "/"?

Either would work. Putting in the repeater's call sign (with the required / 
and port letter) guarantees your signal reaches that repeater. There is a 
delay in propagating user key-ups to the network. I'm not sure how long it 
is now, but maybe 10 minutes or so? So if the person has been bopping 
around several local repeaters, the network might not be quite up to date 
on the last key-up, while the info on dstarusers.com is updated instantly. 
When you don't have access to dstarusers.com, putting in their calls sign 
(no /, no port letter) is the safer bet, unless you know they only monitor 
one repeater.

>Another Example:
>
>I was told to set UR to UR:REF001CL (no slash), to connect to a reflector 
>and just listen to what is going on. Then change it to UR: U (<- 8th 
>position), to disconnect. Is "C" the port number? What is the "L"?

That's correct, though you'll do more than listen.  If you transmit (with 
CQCQCQ back in your UR field, you'll also transmit to the reflector.

In this case, the C is the port letter of the reflector (done that way to 
be similar to the way repeaters work - each reflector is actually three 
reflectors, A, B and C - the letters have nothing to do with an RF band). 
And it's in the 7th, not 8th, position. A little confusing, but the guys 
who designed it needed the 8th position for the L, which is the instruction 
to initiate the link.

>If I just wanted to listen in on the San Diego repeater, would I enter:
>UR:KI6KQUBL and just key the mic or is there something else required to 
>just monitor a specific repeater?

That's right - just key the mic, and the info you've entered does the rest. 
The repeater will announce that it's linked (or that the other repeater is 
busy or unavailable). No touch-tone keying, etc.  Doing what you describe 
would link your repeater to the San Diego UHF repeater. It's a two-way 
link, so any transmissions on your repeater would go out in San Diego as 
well. As far as I know, the ability to just "monitor" hasn't been built in. 
I suppose it could be, though that might be confusing to the local users.

Once you make your "link-me" key-up, be sure to change your radio back to 
having CQCQCQ in your UR field, or the "link-me" instructions will get sent 
every time you key up, and your actual transmissions won't be heard (at 
least I think they won't - I'm not sure of that last point).

>Eventually I will catch on to all of this. Right now, the more I learn, 
>the more questions I have.
>
>Mike
>KC7VE

We're all still learning!

73,
Gary KN4AQ

ARVN: Amateur Radio//Video News
Gary Pearce KN4AQ
508 Spencer Crest Ct.
Cary, NC 27513
<mailto:[email protected]>[email protected]
919-380-9944
www.ARVideoNews.com  

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