Trunking on Motorola APX7000XE StarCOM21 question.

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pgomez971

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So I have a general question that may apply to any trunking system similar but I am specifically talking about STARCOM21 in this case. So if you will refer to https://www.radioreference.com/apps/db/?sid=2324 this link to see how the system is set up.

On with the point. I have already set up my Motorola APX7000XE to monitor the system successfully for the Illinois State Police District Chicago system using the "Cook South - Simulcast [P2]". Here's where things get hairy. I only used those simulcast frequencies or rather knew to use them because there is a YouTuber I've seen broadcasting ISP DChi with a scanner and the scanner shows the specific frequencies it listens to when the users are talking. I took those frequencies and used (ctrl+f) to find which simulcast it was I needed to program.

Other than what I did, I do not know how to find the frequencies for what I want to listen to. Because all the frequencies are in the same system, does this mean I can program any frequency close to me to listen to anything on the system or do I need to program a specific set? I'm sure it's the second one but need to find out how without buying a scanner. I kind of already spent a lot on this APX... Any help will be appreciated brothers/sisters.
 

usswood

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So I have a general question that may apply to any trunking system similar but I am specifically talking about STARCOM21 in this case. So if you will refer to https://www.radioreference.com/apps/db/?sid=2324 this link to see how the system is set up.

On with the point. I have already set up my Motorola APX7000XE to monitor the system successfully for the Illinois State Police District Chicago system using the "Cook South - Simulcast [P2]". Here's where things get hairy. I only used those simulcast frequencies or rather knew to use them because there is a YouTuber I've seen broadcasting ISP DChi with a scanner and the scanner shows the specific frequencies it listens to when the users are talking. I took those frequencies and used (ctrl+f) to find which simulcast it was I needed to program.

Other than what I did, I do not know how to find the frequencies for what I want to listen to. Because all the frequencies are in the same system, does this mean I can program any frequency close to me to listen to anything on the system or do I need to program a specific set? I'm sure it's the second one but need to find out how without buying a scanner. I kind of already spent a lot on this APX... Any help will be appreciated brothers/sisters.
go to this link first... https://www.radioreference.com/apps/db/?sid=2324#tgs here you can find the different tower Freq's and Locations...now you say you have Cook South in the radio... scroll down to Chicago (Cook County) in the Talk-group area... you need to program the Talkgroups of the agency's you want to monitor..i.e Glenview Fire Dispatch is talkgroup 3679 and it is Phase II (T indicator tells you this) and so on, then your all set!
 

FFPM571

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are you trying to use Non Affiliate scan? or listening to the just the voice channels?
 

pgomez971

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How does the system work?

I am using the non-affiliate trunk scan method for ISP District Chicago. Trust me, it took me long enough and at this point, I am sure that I know what I am doing when it comes to setting up a non-affiliate trunking scan.

What I don't understand is the STARCOM21 layout. I've had experience with simpler trunking systems where it is one group of towers for one group of talkgroups. Those are easy because you know what sites to use because there is only a few.

STARCOM21 is the only system I have seen with many large bundles of tower locations to chose from with different site numbers and what not. Now I don't understand if you connect to one group to gain access to ALL talkgroups of the entire system or?

Basically speaking, can I listen to ANY listed talkgroup on STARCOM21 using any listed "site location group" on STARCOM21? For instance with the Cook South Simulcast P2 can I listen to IDOC or lets say Carbondale ISP and vice versa listen to District Chicago ISP from Carbondale using some tower group near me in southern Illinois?
 

MikeyC

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Basically speaking, can I listen to ANY listed talkgroup on STARCOM21 using any listed "site location group" on STARCOM21? For instance with the Cook South Simulcast P2 can I listen to IDOC or lets say Carbondale ISP and vice versa listen to District Chicago ISP from Carbondale using some tower group near me in southern Illinois?
You'll only be able to hear talkgroups that have radios affiliated to the tower that you're listening to (and that are "allowed" on the site). ISP Dist 2, 5, 15 and Chicago plus a slew of IDoT, Tollway and all of the local agencies that are on Starcom that aren't encrypted will be available to you.
 

pgomez971

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You'll only be able to hear talkgroups that have radios affiliated to the tower that you're listening to (and that are "allowed" on the site). ISP Dist 2, 5, 15 and Chicago plus a slew of IDoT, Tollway and all of the local agencies that are on Starcom that aren't encrypted will be available to you.
See that makes sense then. How did you go about finding what agencies were available to you by tower group? That is what I don't understand. The STARCOM21 layout is a bit vague on that behalf.
 

rbrtklamp2

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You have to be familiar with the simulcast towers layout and what falls under what simulcast location. You'll need a map and also figure out what towers you are in range of then list the agencies you can hear on exh tower/simulcast then start making scan lists.

Sent from my SM-N960U using Tapatalk
 

MikeyC

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See that makes sense then. How did you go about finding what agencies were available to you by tower group? That is what I don't understand. The STARCOM21 layout is a bit vague on that behalf.
It depends on where you live and what you want to listen to. This is where the scanners (especially the newer ones) have the advantage over commercial radios. I have all of the talkgroups and 14,000 radio IDs in my "Starcom favorites list" (plus scan with ID search on) so it doesn't matter who affiliates with my site - I hear it or can lock it out if I don't really want to hear Ameren turn on electrical power in Peoria ;)

If you want to listen to ISP, figure out which ISP district you're in and scan the A and B talkgroups (and C if there is, or in Dist Chicago's case, a few more). If you're in DuPage County or Will County there's a chance you can hear the local PDs and FDs on there. If you're in Cook County that's probably out of the question.

Don't forget IDoT which should be interesting listening during the "snow event" tomorrow.

I guess it all comes down to what you're wanting to hear
 

pgomez971

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It depends on where you live and what you want to listen to. This is where the scanners (especially the newer ones) have the advantage over commercial radios. I have all of the talkgroups and 14,000 radio IDs in my "Starcom favorites list" (plus scan with ID search on) so it doesn't matter who affiliates with my site - I hear it or can lock it out if I don't really want to hear Ameren turn on electrical power in Peoria ;)

If you want to listen to ISP, figure out which ISP district you're in and scan the A and B talkgroups (and C if there is, or in Dist Chicago's case, a few more). If you're in DuPage County or Will County there's a chance you can hear the local PDs and FDs on there. If you're in Cook County that's probably out of the question.

Don't forget IDoT which should be interesting listening during the "snow event" tomorrow.

I guess it all comes down to what you're wanting to hear
So I've never owned or used a legit scanner device that sniffs like that. I guess that's an explanation why I need one. So on those you can program a tower site near by and hear anything that affiliates to it?! woah
 

VASCAR2

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I program in several sites as your likely to hear more users that aren’t affiliating with one site. With ISP the mobile/portable radios only affiliate with a specific tower determined by location and programming. If they are voting a different site they won’t hear if a unit is on Car to Car or one of the detail TG’s. By listening to only one tower your likely going to miss traffic. For Trunked user if he hears units going to a different TG he can switch his radio to that TG and listen if his radio is voting a different tower/site. The Trunked mobile and portables have a scan feature but it only hears TG’s that are transmitted on the tower/site his radio is affiliated/voting. With the ISP only TG A-Dispatch and ISPERN TG are simultaneously transmitted on all SC21 towers/sites close to the geographic area of the State Police District. Any other TG the user hears has to be affiliated/voting the same tower as the user.


The Tower/Site acts like a router for a computer in your home giving the user a lot of access through the internet but not information passed by your neignbors router.


It makes less difference if the only sites/towers you can receive are in a simulcast network. All traffic from TG’s from affiliated mobiles/portables will be transmitted at the same time on all simulcast sites and as long as you can hear one site clearly your hearing everything. The problem for scanners is the time distotion from different site locations reaching scanners is problamatic. The newer Uniden SDS100 scanners are getting better reception in simulcast P25 trunked systems because the scanners are designed to work better in multi site simulcast systems.
 
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