Please school me on LTR TGID info

[Jay911]

Here's a noobish question I can't find a response for.

Trying to figure out some users on still-in-use LTR systems in my area. The last three digits of the TGID, does that indicate it's the same agency/user? For example are 0-02-020 and 0-11-020 the same TG or at least (likely to be) the same agency but different TGs?

I've read all the standard tutoring on how to decipher an LTR TGID but that particular tidbit has never shown up in anything I've seen.

Thanks in advance...

 

[ka3jjz]

Maybe this helps...according to this, the last set of digits are a group number that goes from 001-254

Logic Trunked Radio - The RadioReference Wiki

wiki.radioreference.com

Mike

 

[Jay911]

Didn't look in our wiki, did you? There's a section here on LTR Standard and how to read the TGs

Logic Trunked Radio - The RadioReference Wiki

wiki.radioreference.com

Mike

Um yeah, actually I did.

I've seen this section both here and in multiple websites across the interwebs:

LTR Standard talkgroups are written in the format A-HH-GGG.

• "A" is the area code and is either 0 or 1. The area code is the same for all talkgroups in a given system and is arbitrarily chosen by the system operator; the most common use is to simply distinguish between talkgroups on multiple systems.
• "HH" is the home repeater number and has twenty possible values, 01 through 20. A talkgroup will always use its home repeater by default, unless the repeater is already in use by another talkgroup. If the home repeater is in use, the controller will assign another free repeater at random. If no repeater is free (all are in use), then the radio will receive a busy signal.
• "GGG" is the group number and has 254 possible values, 001 through 254.

That's kind of ambiguous to me. Is there only one GGG in a given system? Using my above example, is group number 020 the same people regardless of what home repeater shows up? I'm operating on the understanding/presumption that 0-09-020 shows up when the group 020 is transmitted over repeater 9, and if the same conversation on the same radios on the same talkgroup happened to be on repeater 11, the TGID would show as 0-11-020 instead. In other words, should 0-09-020 and 0-11-020 be considered the same talkgroup (as well as 0-02-020, and any other 0-xx-020)? Or is 0-09-020 one agency/set of users and 0-11-020 a completely different set of users/radios?

 

[KevinC]

LTR doesn't use "Talkgroups", it uses area/home channel/group. So group 020 on home channel 1 has no correlation to group 020 on home channel 2 (or whatever home channel/group you choose).

 

[Jay911]

Thank you, that's what I was looking for.

 

[KevinC]

Going to reminisce...

LTR was fun, you needed to balance the users between home channels as well as not just number home channels in order. If you had a 5 channel system you used channels 1, 5, 10, 15 and 20, otherwise the data stream would act up expecting channels above 5 to be assigned. Another quirk was most LTR validators didn't block groups 251-254 and you could bootleg on any system that you wanted to (251-254 were "system" groups and not to be used for voice).

Fun times.