P25 Talkgroup programming question

spitzman

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Joined
Jan 10, 2012
Messages
11
Location
Washington, IL
So I think I know the answer, but I have to start somewhere. I am programming a scanner with the P25 Starcom Statewide system. I live in Washington, IL and I've locked onto a tower in Metamora, IL, very close to me. My question is, can I program any talk group in my scanner and listen since I'm connected to the Metamora P25 tower? Or are there geographical limits in that a TG from Northern IL isn't broadcasted in Central IL?

I'm asking because on this portable scanner, I've programmed the Peoria County Fire TGs but I'm not hearing any traffic. I am listening to the Peoria County Digital scanner feed, figuring what I hear there should match what I hear on the scanner, but it doesn't.

Thanks for the help! I realize this is probably a noob question, but this is my first run-in with P25 in IL.
 

cmjonesinc

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Apr 25, 2011
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Since you are using a scanner you are passively monitoring the tower. So if the tower isn't carrying the talkgroup you want to hear you aren't going to hear it. Now if a subscriber unit on the system affiliates with that site and is requesting that talkgroup (and the system is set to allow it on that site) you will then hear it. Different systems limit which talkgroups can be carried on certain towers so even an actual subscriber may not even be able to get a certain talkgroup on a certain tower. Sorry if that's confusing. Ask away if you have any other questions.
 

spitzman

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Jan 10, 2012
Messages
11
Location
Washington, IL
That sort of confirms what I was thinking. So in my particular case I'm focusing on wanting to hear Peoria County Fire Dispatches so I'll probably need to hit a tower within the Peoria County limits.

Thanks for your help!
 

N9JIG

Sheriff
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To expand on the original answer you need to understand how "Affiliation" works. A system radio (not a scanner) sends a signal to the system and says "This is me, here I am". This signal tells the system that a particular radio is set to a specific talkgroup and has affiliated with that tower. When that is done that talkgroup will be heard on that tower.

In your situation, with Metamora being fairly close to Peoria you MIGHT hear some Peoria traffic if Peoria radios affiliate with the tower in your area.

There are some exceptions of course. Some talkgroups or radios can be blocked from certain towers. For example:
  • A Rockford PD unit might not be allowed to affiliate with a tower in Peoria so a visiting officer would not tie up resources that may be needed by locals.
  • Some users might be restricted to certain towers for their regular channels but have "Statewide" or "Travel" talkgroups that work anywhere on the StarCom21 system.
  • The agency I used to work for have SC21 radios that were restricted to certain towers but the Statewide talkgroups worked anywhere in Illinois so when I went to Springfield, Peoria or Champaign I could call my dispatcher.
 

spitzman

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Joined
Jan 10, 2012
Messages
11
Location
Washington, IL
That helps clarify some things too. I was able to change my site list to only have the Peoria towers and I can hear all the traffic I want to. I'm on a volly fire dept here so I understand what you mean with the statewide talk groups (MABAS, etc)

Thank you!
 
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