P25 towers and talk groups

[galligan122]

I apologize if this has already been covered, I have looked, but haven’t seen the answer to my question.

When I’m programming a trunking system, on a Pro-106 scanner, I have a scan list for each county I want to monitor, plus one or two scan lists for misc. state / federal agencies. I have a decent understanding of how towers and talk groups correlate with each other. I have not found anything concrete though if it is ever a case where two counties might share a tower and allow talk groups from each county on the tower. Especially smaller counties with fewer talk groups and not as much strain.

Typically I use software and RR to program the tower control channels for each county, and only include those frequencies associated with the tower(s) for that county and talk groups for that county in each scanlist.

My question is, do towers located in one county, ever let surrounding counties share their tower, allowing their talk groups to be used on either tower?

For example, I scan the county just west of mine, and the county west of that. I receive both but of course, the closer county comes in much clearer. Would there be any chance that the county west of mine would get talkgroups from the county west of them on their, therefore being better signal for me? Same with all the other surrounding counties.

Just want to make sure I’m putting in all the towers I should be when I scan and not shorting myself.

Thanks!

 

[RaleighGuy]

My question is, do towers located in one county, ever let surrounding counties share their tower, allowing their talk groups to be used on either tower?

First, I'm guessing this is a statewide system they share, not two different systems. If that is the case, It varies by system and users, each system can set it up how they want. They can decide if roaming is allowed, or if units are restricted to one tower/site. If roaming is allowed then it will depend where the units are at any given time whether they can affiliate with other sites/towers. If there are no units affiliated with that site you won't hear any traffic. Keep in mind, not all traffic is on all sites, so it is good to include all towers/sites in range.

If it is two different systems, it is very unlikely except for mutual aid TGs.

 

[galligan122]

First, I'm guessing this is a statewide system they share, not two different systems. If that is the case, It varies by system and users, each system can set it up how they want. They can decide if roaming is allowed, or if units are restricted to one tower/site. If roaming is allowed then it will depend where the units are at any given time whether they can affiliate with other sites/towers. If there are no units affiliated with that site you won't hear any traffic. Keep in mind, not all traffic is on all sites, so it is good to include all towers/sites in range.

If it is two different systems, it is very unlikely except for mutual aid TGs.

Thank you for the reply! Yes, specifically this is the Hoosier Safe-T system mostly, with the exception of one of my scanlists.

It sounds like then, that the suggestion would be to add more control frequencies to my scan list. For instance, if I am scanning something two counties west of me, I should also include in the county tower frequencies that are just west of me in case it does hit on that tower.

Essentially, I currently add the respective counties primary control frequencies, and then that counties talk groups and nothing else for each county that I scan, then toggle which counties I want to hear at a particular time. For the state agencies, I did add all towers I can receive and then selected which groups I wanted to hear.

I am assuming that there is no way to figure out which towers allow which talk groups access, so trial and error is the way to go?

 

[RaleighGuy]

Thank you for the reply! Yes, specifically this is the Hoosier Safe-T system mostly, with the exception of one of my scanlists.

It sounds like then, that the suggestion would be to add more control frequencies to my scan list.

Yes and no, you don't want to pile a bunch of control channels (CCs) in one system, you need to set them up by sites, otherwise it may not work correctly, you can combine multiple sites into on scan list/bank though.

I am assuming that there is no way to figure out which towers allow which talk groups access, so trial and error is the way to go?

No, other than lots of monitoring and logging who is where, there is no way to tell for sure unless you are a comm tech for the agency.

 

[galligan122]

Yes and no, you don't want to pile a bunch of control channels (CCs) in one system, you need to set them up by sites, otherwise it may not work correctly, you can combine multiple sites into on scan list/bank though.



No, other than lots of monitoring and logging who is where, there is no way to tell for sure unless you are a comm tech for the agency.

Thank you! Elaborating on the CCs, obviously I wouldn’t put towers south of me in if I’m scanning north of me. But would my counties CC’s, the county I want, and then if there is a tower between me and the county I’m scanning, should they all be included?

 

[gmclam]

My question is, do towers located in one county, ever let surrounding counties share their tower, allowing their talk groups to be used on either tower?

Yes. Each system has its own personality. You'll find a system where the "tower" for a given county is not only in another county, but in another state. It happens because that's where the highest point is to get the best coverage.

For example, I scan the county just west of mine, and the county west of that. I receive both but of course, the closer county comes in much clearer. Would there be any chance that the county west of mine would get talkgroups from the county west of them on their, therefore being better signal for me? Same with all the other surrounding counties.

Yes. The functionality depends on the type of system and how it was designed. It's common for only "affiliated traffic" to be broadcast from a given tower, which means you might not hear them on a tower close to you (as it's 'not where they are'). You can't get caught up in the physical location of a tower/site, but have to look at its coverage area. It's also common to have "two antennas" on one tower/site, one pointed "east" and one pointed "west". I am using quotes because I don't mean this literally, but I think you understand.

Just want to make sure I’m putting in all the towers I should be when I scan and not shorting myself.

In non-simulcast systems, I think many people overlook this issue. What I see happen is people program in all the sites and let the scanner pick the strongest one. You could program the sites as separate objects (duplicating the TGs), but you also don't want to overload the scanner trying to pick up more than you need. It's a tricky proposition, especially when mobile.

 

[hiegtx]

I am assuming that there is no way to figure out which towers allow which talk groups access, so trial and error is the way to go?

There's nothing in the database itself that specifies which sites are used for a specific user, such as a city or county. That's something that is determine by the administrators for the system.

It sounds like then, that the suggestion would be to add more control frequencies to my scan list. For instance, if I am scanning something two counties west of me, I should also include in the county tower frequencies that are just west of me in case it does hit on that tower.

Yes and no, you don't want to pile a bunch of control channels (CCs) in one system, you need to set them up by sites, otherwise it may not work correctly, you can combine multiple sites into on scan list/bank though.

I would note that the OP indicated, in the first post in this thread, that the scanner being used is a Pro-106. That's an "Object Oriented" scanner, so you don't have the structure of sites such as the way that Uniden handles sites. For the Pro-106, and all of the related scanners that are 'object oriented', you have a 'site' that is part of the system being programmed, which can contain up to 32 frequencies. So, in the case of a county, or a specific agency, that operates over an extended area, you would likely want the frequencies for the sites in the specific area to be in the 'site' as opposed to duplicating the talkgroups by creating a separate system for each site.

The object oriented scanners have a limit on how much can be programmed & scanned at one time. So, you would enter only the control channels for each site in the area being scanned, and also program the talkgroups for that area. Since the 'site' in the system being programmed allows the programming of 32 frequencies, presuming an average of 4 control channels per site (primary & alternate control channel frequencies), you can combine up to 8 sites in one system of a given scanlist.

Using the multi-site choices available, you can specify that the scanner handle the sites by one of several methods.

Scan the control channel with the best signal
or
Scan a different control channel frequency (in other words, a different site) each time that specific system is accessed in it's scanlist
or
Instruct the scanner to check all of the programmed site frequencies each time that system is scanned.

 

[RaleighGuy]

There's nothing in the database itself that specifies which sites are used for a specific user, such as a city or county. That's something that is determine by the administrators for the system.

Thank you for that information

 

[galligan122]

There's nothing in the database itself that specifies which sites are used for a specific user, such as a city or county. That's something that is determine by the administrators for the system.




I would note that the OP indicated, in the first post in this thread, that the scanner being used is a Pro-106. That's an "Object Oriented" scanner, so you don't have the structure of sites such as the way that Uniden handles sites. For the Pro-106, and all of the related scanners that are 'object oriented', you have a 'site' that is part of the system being programmed, which can contain up to 32 frequencies. So, in the case of a county, or a specific agency, that operates over an extended area, you would likely want the frequencies for the sites in the specific area to be in the 'site' as opposed to duplicating the talkgroups by creating a separate system for each site.

The object oriented scanners have a limit on how much can be programmed & scanned at one time. So, you would enter only the control channels for each site in the area being scanned, and also program the talkgroups for that area. Since the 'site' in the system being programmed allows the programming of 32 frequencies, presuming an average of 4 control channels per site (primary & alternate control channel frequencies), you can combine up to 8 sites in one system of a given scanlist.

Using the multi-site choices available, you can specify that the scanner handle the sites by one of several methods.

Scan the control channel with the best signal
or
Scan a different control channel frequency (in other words, a different site) each time that specific system is accessed in it's scanlist
or
Instruct the scanner to check all of the programmed site frequencies each time that system is scanned.

Thank you for this information! If I add multiple sites to a particular group of TG’s I want to scan, and then set to check all site frequencies, does this give me the best chance to catch the traffic? Also, does that slow down how quickly the scanner searches for incoming radio traffic?

 

[tvengr]

It would help to know which systems and agencies you want to monitor. The PRO-106 is capable of P25 Phase 1 only and may experience simulcast distortion depending upon your location. I have seen several instances where the site for a city may be on the other side of a river in another county or state. Your city or town will also be helpful to determine the best sites. Are you using programming software or programming manually using the scanner menus? If your county has its own system with a single site, set Multi-Site to Off. You only need to enter the red control channel capable frequencies into the frequency list. If a county has multiple sites, setting Multi-Site to Roam will cause the scanner to find a strong signal from a control channel in the frequency list and stay on that site until it loses the signal and then searches for a control channel in another site. If Multi-Site is set to Stationary, the scanner will scan all sites whose control channels are in the frequency list.

 

[galligan122]

It would help to know which systems and agencies you want to monitor. The PRO-106 is capable of P25 Phase 1 only and may experience simulcast distortion depending upon your location. I have seen several instances where the site for a city may be on the other side of a river in another county or state. Your city or town will also be helpful to determine the best sites. Are you using programming software or programming manually using the scanner menus? If your county has its own system with a single site, set Multi-Site to Off. You only need to enter the red control channel capable frequencies into the frequency list. If a county has multiple sites, setting Multi-Site to Roam will cause the scanner to find a strong signal from a control channel in the frequency list and stay on that site until it loses the signal and then searches for a control channel in another site. If Multi-Site is set to Stationary, the scanner will scan all sites whose control channels are in the frequency list.

Thank you.

I am in the southern portion of Wabash County Indiana. Essentially I listen to everything that I can reach. I have a DPD 800 MHz antenna being delivered this week which I think will help me a lot.

I do use programming software. I have zero issue picking up radio traffic in my own county, and also Miami County. I can pick up Grant County also, but they went Phase 2 so I have to put in the frequencies with no talk groups and I can hear traffic that way, just with no ID’s showing up. As soon as I add the talk groups I get nothing. The joys of a phase 1 scanner lol. Same with Howard county. At least until I get a new scanner, which I am soon.

I just didn’t know the best method to get the best range out of my scanner as far as entering sites. I occasionally receive blackford, Delaware Cass and a few others but I didn’t know if there was a best practice in putting in sites for best performance.

 

[tvengr]

The database shows that Grant County is Phase 2 capable but all of the talkgroups still show as Phase 1. It is possible that the database has not been updated to show talkgroups are Phase 2. The system may be operating in dynamic dual mode where Phase 2 talkgroups revert to Phase 1 when a Phase 1 radio affiliates with the system. Many of the talkgroups are encrypted which no scanner can receive. You will not be able to hear any talkgroups on the Grant County system unless you have a Wildcard if no talkgroups are programmed. You may just be hearing the conventional frequencies and not the talkgroups on the trunked system. In the database, Mode D is Phase 1 and Mode T is Phase 2. Modes DE and TE are fully encrypted. Modes De and Te are encrypted part of the time. If yo attach your programming file, I will be happy to take a look at it. I have ARC500, Win500, and PSREdit500. You will need to zip the file to be able to attach it. Click on Attach files and open the zipped file.

 

[RichM]

Enable the “Wildcard” feature and you will hear every talk group that comes within range of a tower. I always have it on, it’s a great way to discover new talk groups as well as hearing other counties when their radios are in range. Instructions are on page 19 of the easier to read manual or page 35 of the hard copy manual. Incidentally the “easier to read” version does not have a section title for Wildcard so while it may be easier to read it is not easier to locate this information. Hard copy is superior in this regard. Hope this helps, good luck.

 

[galligan122]

The database shows that Grant County is Phase 2 capable but all of the talkgroups still show as Phase 1. It is possible that the database has not been updated to show talkgroups are Phase 2. The system may be operating in dynamic dual mode where Phase 2 talkgroups revert to Phase 1 when a Phase 1 radio affiliates with the system. Many of the talkgroups are encrypted which no scanner can receive. You will not be able to hear any talkgroups on the Grant County system unless you have a Wildcard if no talkgroups are programmed. You may just be hearing the conventional frequencies and not the talkgroups on the trunked system. In the database, Mode D is Phase 1 and Mode T is Phase 2. Modes DE and TE are fully encrypted. Modes De and Te are encrypted part of the time. If yo attach your programming file, I will be happy to take a look at it. I have ARC500, Win500, and PSREdit500. You will need to zip the file to be able to attach it. Click on Attach files and open the zipped file.

Thank you for the response. I programmed via ARC500 again this morning to make sure I had it right. It will not receive any Grant County radio traffic at all via the default RR ARC 500 setup on the Grant County Government Trunking System. If I program each of the site frequencies into a bank as separate frequencies though and scan those frequencies as conventional digital, I hear the radio traffic. I just, of course, don't get the TGID's telling me who is talking.

 

[gmclam]

I would note that the OP indicated, in the first post in this thread, that the scanner being used is a Pro-106. That's an "Object Oriented" scanner, so you don't have the structure of sites such as the way that Uniden handles sites. For the Pro-106, and all of the related scanners that are 'object oriented', you have a 'site' that is part of the system being programmed, which can contain up to 32 frequencies. So, in the case of a county, or a specific agency, that operates over an extended area, you would likely want the frequencies for the sites in the specific area to be in the 'site' as opposed to duplicating the talkgroups by creating a separate system for each site.

I own the PSR-500 equivalent of the PRO-106 and know what I am talking about. I understood the OP's questions. My suggestion, is to create two separate TSYS objects for the SAME system but enter different site frequencies in each. And this requires each TSYS to have what amounts to a duplicate set of TGRP objects. This gives him total control over which of the sites he wants to monitor, as each TSYS would only have a single site programmed (therefor no search is required). It's certainly easier to use a Wildcard TG for each, but then you'll only see TG IDs and not your personalized alpha tags.

The object oriented scanners have a limit on how much can be programmed & scanned at one time. So, you would enter only the control channels for each site in the area being scanned, and also program the talkgroups for that area. Since the 'site' in the system being programmed allows the programming of 32 frequencies, presuming an average of 4 control channels per site (primary & alternate control channel frequencies), you can combine up to 8 sites in one system of a given scanlist.

You mean 8 sites in each given TSYS (not scanlist) objects. The total number of objects that can be programmed is just over 1800. Yes this takes up programming space but it is apparently the main (only?) system that he wants to monitor. You have 20+ lists, that can be assigned as desired to objects.

Using the multi-site choices available, you can specify that the scanner handle the sites by one of several methods.

Scan the control channel with the best signal
or
Scan a different control channel frequency (in other words, a different site) each time that specific system is accessed in it's scanlist
or
Instruct the scanner to check all of the programmed site frequencies each time that system is scanned.

Yeah, but if you don't like those options and want to "force" the scanner to scan two separate sites of the same system, you need more than one TSYS. You don't want to force the scanner to check all the frequencies each time around as that slows everything down. Using 2 TSYS objects it will keep track of the active CC in each TSYS and only have to scan those.

 

[galligan122]

I just did this and it was exactly what I was looking for to monitor what agencies used what towers. Thanks!