Determining Which P25 Simulcast

[CTWaters]

Good morning all.

Anyone know if there is any way on Radio Reference for a P25 System listed, to tell which "System" is assigned to what Simulcast?

For instance...

Simulcast 1, 2, 3, 4, 5
PD 1, 2, 3

Is there an easy way to tell that PD 2 is only on S/C 2, but PD3 is on all five S/C's, and PD 1 is only on S/C 2, etc?

 

[RaleighGuy]

Simulcast means all traffic is on all towers, there is no difference between towers of a simulcast system, they use the same frequencies and talkgroups which is what causes the problems, same traffic coming in to the scanner from different towers at a fraction of time different.

 

[slayer816]

Which system in particular are you referencing?

A P25 "system" has multiple sites which may be standalone (1 tower 1 set of frequencies) or simulcast (multiple towers each with the same set of frequencies functioning as one site). Simulcast sites cause issues as listed above with non-SDS radios as they are not built to handle the distortion properly. Each "site" is linked to each other and allow a talkgroup to be used across the system regardless of site. Some sites of some systems do blacklist certain talkgroups, but ignoring this; any talkgroup can "affiliate" with any site at any time.

Without discussing how a P25 system works in relation to sites/systems/talkgroups further, there is no easy way to tell which site is affiliated by which talkgroups because by nature, sites are capable of receiving any talkgroup on the system and broadcast that talkgroup to the rest of the sites. In a sense, that's what makes the system useful. You will find a site or a few sites where the majority of the talkgroups' users affiliate with, but if a radio on that talkgroup affiliates with a site 100 miles away (provided its on the system or patched); BOOM that site carries that talkgroup even if it has never done so before.

SDR software such as Unitrunker or DSD+ will display live data concerning these affiliations.

 

[CTWaters]

Maybe I asked the question wrong... So here in the Phoenix area, there are some systems that are simulcast (S/C) on S/C A but not B, and D but not G, etc.

So my question was, is there a way to find out what "system" that is part of the complete Regional Wireless Co-Op is on what?

For instance... Phoenix PD is broadcast on S/C A, and only some are on S/C B. Glendale PD South is on both S/C B & G, but Glendale PD North is only on S/C G. Scottsdale PD South is Broadcast on S/C South Mountain High but not H, and both North and South are on H but not South Mountain High.

That kind of thing...

 

[RaleighGuy]

So my question was, is there a way to find out what "system" that is part of the complete Regional Wireless Co-Op is on what?

No, there is no way, other than monitoring and logging, to determine which site TGs are assigned to, if I understand the question correctly. Also, keep in mind that there may be roaming permissions with the ability to affiliate to other sites as units travel to other areas, while the unit is affiliated you'll hear all traffic until the unit leaves (unaffiliated).

 

[slayer816]

Ditto

SDR viewing helps but I count this as "monitoring and logging"

Edit: Looking over the system Regional Wireless Cooperative (RWC) Trunking System, Phoenix, Arizona This is the first time I've ever seen site names containing certain services. This does imply certain talkgroups are on certain sites. Very weird. Someone else that monitors this system (RWC P25) may be more helpful.

 

[slayer816]

Sorry, I've edited my post so much I need to make a new one.

The site names are implying they only affiliate certain talkgroups. If I didn't know the system and was programming, I would for sure think like you are thinking and be confused about which agencies affiliate on which sites. It is very possible that they block certain talkgroups from being able to affiliate on certain sites. SDR would tell you within a minute.

Perhaps a local forum post would gather the attention of someone with more experience with this specific system (RWC P25).

 

[RaleighGuy]

This old thread may help answer your question better @CTWaters, it appears several years ago others have done the research.

Comprehensive list what citie/sites

Does anyone on here have a comprehensive list of all trunking sites and which site a particular city woud use. Such as for El Mirage PD, all you would need is sim. G, that way you could delete the other 14 sites that the programmer puts when programming.It seems like there's alot of sites that...

forums.radioreference.com

 

[slayer816]

Thanks for that, I was also looking through the Arizona Forum for info.

-RWC System Admins control what talkgroups have access to what sites.

This is the "blacklisting" I was referring to earlier. It does make sense for efficiency at this level of radio users on a P25 system.

 

[CTWaters]

Sorry, I've edited my post so much I need to make a new one.

The site names are implying they only affiliate certain talkgroups. If I didn't know the system and was programming, I would for sure think like you are thinking and be confused about which agencies affiliate on which sites. It is very possible that they block certain talkgroups from being able to affiliate on certain sites. SDR would tell you within a minute.

Perhaps a local forum post would gather the attention of someone with more experience with this specific system (RWC P25).

You would think, right!? We have so many valleys and mountains here in the Phoenix Metro Area, it makes tracking them all wEiRd! For instance.. That S/C H (Scottsdale) has both South and North, but you need to be in the Scottsdale proper area in order to get that S/C. However, South I believe it is is broadcast on S/C B (along with a boat ton of other agencies), which is labeled Phoenix Fire. S/C C is the only site Chandler is broadcast on, but that also broadcasts the contents of Phoenix Fire. S/C T not only does Tempe, but the surrounding agencies that you don't hear on any of the other S/C's. And the West Valley S/C broadcasts 80% of everything - PD, City Services, Interagency, etc., but doesn't broadcast Phoenix Fire.

It's a very convoluted configuration, but I know there is a reason for the mayhem.

 

[Foresigt]

Part of it is that the system isn't designed to be listened to by scanner. The radio people don't care what we think. Radios affiliate to wherever they need to be. The fact that our scanners can't communicate with the control channels puts us at a huge disadvantage. There is are reasons why things are set up the way the are and it's for them not us. I hope this doesn't come across and being crappy but it's just a facts of life when it comes to scanning in today's world. Oh for the old analog days when things were simple.

 

[DanRollman]

Part of it is that the system isn't designed to be listened to by scanner. The radio people don't care what we think. Radios affiliate to wherever they need to be. The fact that our scanners can't communicate with the control channels puts us at a huge disadvantage. There is are reasons why things are set up the way the are and it's for them not us.

This is all true. But all that said, it absolutely is possible to learn what Simulcasts (or other Sites) a particular agency or talkgroup can "always" be heard on. Maybe they are sometimes also heard on other sites as needed, and you have no control over that, but you can at least know that "so long as I can hear Simulcast X or Y, I can always receive Talkgroup Z. If I can't hear Simulcast X or Y where I am, I can hear Talkgroup Z on on Simulcast W at a lot of the time, but I only know for certain that I can always hear it on Simulcast X or Y." Most major multi-site P25 systems lack this sort of information on RR, and it is in my view the most important piece of P25 DTRS information that RR generally does not make a habit of storing and displaying.

Take a look at the PCWIN page on RR to see how I have tried to incorporate this sort of information into the Text field just below each agency name header. I don't live in Tucson anymore. But in my travels there, I have tried to build out this information and add it to RR. Wish the other big metros I frequently travel to had this sort of data on their respective multi-site DTRS page on RR.

In my view the Phoenix RWC page on RR could really use this sort of narrative too.

Pima County Wireless Integrated Network (PCWIN) Trunking System, Tucson, Arizona

Pima County Wireless Integrated Network (PCWIN) Trunking System Profile

www.radioreference.com