P25 ScanList

[W0RS]

I am hoping someone can assist me with a troubleshooting issue on a TRX-2have a scanlist loaded with a P25 system, ie, Sheriff, fire, etc, that I am not hearing. I have double checked and triple checked the “trucked Radio System” tab, site list, talkgroup details, all appears as it should. I have programmed the state patrol P25 system on a different scanlist but can hear everything fine there.

I also have a Bluetail Technologies P25RX, it hears the P25 system I am having issue with just fine. Anyone have any suggestions?

This is a MOSWIN system located in Springfield, MO

 

[hiegtx]

Which site are you programming?

The Greene County Simulcast 800 site is just that- simulcast. While your P25RX can handle it, your TRX-2 may well have problems. The Springfield 700 site is not tagged as simulcast, but since it uses frequencies from the state's allocation, there is no link to show the actual sites of the transmitters. (BTW- it's "trunked", not trunked".)

 

[W0RS]

Which site are you programming?

The Greene County Simulcast 800 site is just that- simulcast. While your P25RX can handle it, your TRX-2 may well have problems. The Springfield 700 site is not tagged as simulcast, but since it uses frequencies from the state's allocation, there is no link to show the actual sites of the transmitters. (BTW- it's "trunked", not trunked".)

While in Omaha, NE a couple of weeks ago, I was receiving there Orion P25 system and it’s a 800mhz simulcast system. What would be the difference?

 

[RaleighGuy]

While in Omaha, NE a couple of weeks ago, I was receiving there Orion P25 system and it’s a 800mhz simulcast system. What would be the difference?

The difference is system and location. My county just switched from a Type II simulcast, which I received fine, to a P25 system that many of us are having trouble with. But, two miles from home I get the new system fine when mobile. I'm using a TRX-1.

 

[tvengr]

I am hoping someone can assist me with a troubleshooting issue on a TRX-2have a scanlist loaded with a P25 system, ie, Sheriff, fire, etc, that I am not hearing. I have double checked and triple checked the “trucked Radio System” tab, site list, talkgroup details, all appears as it should. I have programmed the state patrol P25 system on a different scanlist but can hear everything fine there.

This is a MOSWIN system located in Springfield, MO

This could very well be a simulcast issue. Are you able to receive the Greene Co 800 and Springfield 700 sites in Nixa? The Greene Co 800 site may be a problem only when you are in Greene Co and surrounded by simulcast towers. Even though you may have all 3 sites in Greene Co programmed, the TRX-2 will use only the site with the best signal, so you may be missing transmissions affiliating with the other 2 sites. You can create 3 systems with all of the talkgroups, with each system using a different site. Each system can be assigned to a different scan list. That way, it is possible to scan all 3 sites and select the site or sites you wish to scan. If you attach your TRX-2 configuration file, I will check it for problems.

 

[hiegtx]

While in Omaha, NE a couple of weeks ago, I was receiving there Orion P25 system and it’s a 800mhz simulcast system. What would be the difference?

As mentioned by both N1GAW and tvengr, Simulcast can be a serious impediment to successful listening on many scanner models It is also extremely location dependent.
Simulcast digital distortion - The RadioReference Wiki

If you are very close to one tower site, like a quarter mile or so, the strong, nearby, signals may override weaker, out of sync. signals from more distant sites. If you were directly between two sites, more or less equidistant from you, the combined signal might, again, wash out out of sync transmissions from the other sites. But it can be so location focused that moving your scanner a few feet in one direction or another can be the difference between clear transmissions, and garbled, unusable, receptions. With a residence, moving a few feet might end up shieldng the scanner from spurious signals because the signal path is blocked by something in the house. A refrigerator on the other side of the wall, foil backed insulation in the wall, or metallic siding on the outside could all have an impact. Or, your location may be one where hills or tall buildings, like in an urban downtown area, might block problem transmissions.

While the ORION site in Douglas County is simulcast, if you happened to be close to one of the six towers, your scanner would still work. If you were out & about, driving around the Omaha area, it's likely there would be places where you had good reception, as well as others where you either heard garbled transmissions, or nothing at all.

For Greene County MO, the main MOSWIN is simulcast:



You can see that there are a number of towers spread across your northern horizon, in more than one direction. That would almost certainly be an issue with your TRX-2. Your 925RX is designed to deal with simulcast, and so does not have an issue.


While it has fewer frequencies, and probably carries less traffic than does, the Springfield 700 site might be receivable on your TRX-2. Since it uses frequencies allocated to the state of Missouri, there is no specific site license to pinpoint it's tower location(s) and determine whether or not it is also simulcast.

 

[W0RS]

This could very well be a simulcast issue. Are you able to receive the Greene Co 800 and Springfield 700 sites in Nixa? The Greene Co 800 site may be a problem only when you are in Greene Co and surrounded by simulcast towers. Even though you may have all 3 sites in Greene Co programmed, the TRX-2 will use only the site with the best signal, so you may be missing transmissions affiliating with the other 2 sites. You can create 3 systems with all of the talkgroups, with each system using a different site. Each system can be assigned to a different scan list. That way, it is possible to scan all 3 sites and select the site or sites you wish to scan. If you attach your TRX-2 configuration file, I will check it for problems.

I am able to receive the 700 sites in Nixa on the TRX-2, just the 800 sites are the issue. Both my Unication G5 and P25RX receive all. Both are stellar receivers!

 

[W0RS]

While looking at the Whistler TRX-2 programmer software I just noticed something that perhaps in part, could be a problem. Under the trucked radio system tab I have Missouri statewide selected as the alpha tag, while looking at site details I see all of the sites listed for much of the 700mhz locations with a few in the VHF spectrum. When I scroll all the way to the bottom of the site list I see Green county simulcast, but I do not see any of the site locations for that system, where there should be several. I am now suspicious that this could be my issue? The Green county simulcast 800 system has just been coming on line in the last 30 days or so. The Green county Sheriff dispatch and Springfield public works department are the only agencies that I hear on the G5 and P25RX on a regular basis, Springfield Fire and other county agencies have yet to come on line, just a slow process.

Perhaps I am to quick with faulting the TRX-2 just yet with a simulcast issue. I believe Whistler obtains there data from RF……

 

[W0RS]

As mentioned by both N1GAW and tvengr, Simulcast can be a serious impediment to successful listening on many scanner models It is also extremely location dependent.
Simulcast digital distortion - The RadioReference Wiki

If you are very close to one tower site, like a quarter mile or so, the strong, nearby, signals may override weaker, out of sync. signals from more distant sites. If you were directly between two sites, more or less equidistant from you, the combined signal might, again, wash out out of sync transmissions from the other sites. But it can be so location focused that moving your scanner a few feet in one direction or another can be the difference between clear transmissions, and garbled, unusable, receptions. With a residence, moving a few feet might end up shieldng the scanner from spurious signals because the signal path is blocked by something in the house. A refrigerator on the other side of the wall, foil backed insulation in the wall, or metallic siding on the outside could all have an impact. Or, your location may be one where hills or tall buildings, like in an urban downtown area, might block problem transmissions.

While the ORION site in Douglas County is simulcast, if you happened to be close to one of the six towers, your scanner would still work. If you were out & about, driving around the Omaha area, it's likely there would be places where you had good reception, as well as others where you either heard garbled transmissions, or nothing at all.

For Greene County MO, the main MOSWIN is simulcast:

View attachment 111495

You can see that there are a number of towers spread across your northern horizon, in more than one direction. That would almost certainly be an issue with your TRX-2. Your 925RX is designed to deal with simulcast, and so does not have an issue.


While it has fewer frequencies, and probably carries less traffic than does, the Springfield 700 site might be receivable on your TRX-2. Since it uses frequencies allocated to the state of Missouri, there is no specific site license to pinpoint it's tower location(s) and determine whether or not it is also simulcast.

I think you answered my question concerning the site locations, no specific site licenses. I was hoping it was just a data issue as I indicated below. Oh well…..

 

[hiegtx]

While looking at the Whistler TRX-2 programmer software I just noticed something that perhaps in part, could be a problem. Under the trucked radio system tab I have Missouri statewide selected as the alpha tag, while looking at site details I see all of the sites listed for much of the 700mhz locations with a few in the VHF spectrum. When I scroll all the way to the bottom of the site list I see Green county simulcast, but I do not see any of the site locations for that system, where there should be several. I am now suspicious that this could be my issue? The Green county simulcast 800 system has just been coming on line in the last 30 days or so. The Green county Sheriff dispatch and Springfield public works department are the only agencies that I hear on the G5 and P25RX on a regular basis, Springfield Fire and other county agencies have yet to come on line, just a slow process.

Perhaps I am to quick with faulting the TRX-2 just yet with a simulcast issue. I believe Whistler obtains there data from RF……

For clarity, when you look at the Greene County Simulcast 800 site in MOSWIN, you will only see the single set of frequencies. It's only listed once in the database, which is correct. Each of those transmit sites on the map I posted earlier transmit the exact same radio traffic at the same exact time. So all of the individual towers carry the same thing, at the same time. That's what creates the problem. Your scanner 'hears' the control channel telling the site that a certain TGID is to use a specific voice channel frequency, which is the same on all of the transmit sites. The scanner gets that from the closest site (closest to you) and tries to follow it's instructions, But then the same details, on the same control frequency, arrive at the scanner from another site, helping to confuse it, All these signals, from each site, arrive at your scanner at slightly different times. Yes, the time differential is infinitesimal, but it is still enough to confuse the scanner. So you might get either a garbled transmission, or even nothing at all, if the scanner is hopelessly trying to figure it out. "Professional" radios, such as those actually carried by public safety personnel, are configured to solve the signals arriving out of synch. The SDS100 & SDS200 are also capable of dealing with it, as is your P25RX & the Unication pagers. But for your TRX-2, and any scanner other than the SDS series, you're likely to have problems.

That 700MHz site in Greene County has fewer frequencies, so I suspect it does not carry the same number of talkgroups as are on the 800 MHz simulcast. Program it as well, and see if it carries enough of what you want to hear. Maybe it does, maybe not. There's nothing in the database for this system, nor any other, at any location, that specifies exactly which TGIDs are carried on which site.

 

[tvengr]

I think you answered my question concerning the site locations, no specific site licenses. I was hoping it was just a data issue as I indicated below.

As stated earlier, you may be missing a lot of transmissions by scanning only a single site in Greene Co. If you have all 3 sites in a single system, you are scanning only 1 of the 3 sites. I can't determine if that is the problem if you don't attach the configuration file (the file you send to the scanner to program it). Just click on Attach files and Open the file.

 

[tvengr]

How can Greene/Springfield have that many sites when they only show one 800 site?

That is what is meant by simulcast. The 800 MHz site consists of a number of towers all transmitting the same information on the same frequency at the same time. The signals from each tower arrive at your scanner at slightly different times which degrades the ability of the scanner to properly decode the control channel. That results in missed transmissions and garbled audio. Read the articles about simulcast distortion. The P25RX, Uniden SDS100/200 scanners and Unication G4/G5 pagers are designed to receive simulcast systems. The older scanners are not. Simulcast issues are very location specific. The scanner will or will not work depending upon your location in relation to the towers.

 

[hiegtx]

How can Greene/Springfield have that many sites when they only show one 800 site? Only 35 miles or so range? What would be the sites in Bolivar And Dade county then? And why does that map show over 11 sites and there is only 1, 800 site probably in the Springfield area?

I think what's confusing you is the way the RadioReference database generates the maps. The one that I posted earlier, for the Greene County Simulcast 800, does show a number of sites in other counties,. But the map is actually trying to show sites as designated on the licenses shown on the page. Often, especially on large regional or statewide systems, a license from the FCC will encompass locations in more than one county. So while you see the half dozen or so locations in Greene, you see more in other counties which are likely part of the sites in those counties, not in Greene. The system used for creating the maps does not strip away locations in other counties, and the licensing is only as good as what was submitted to the database. It would take quite a lot of time to manually dig trhough FCC files, for each site, in each system, nationwide or even statewide, and try to physically verify each one. While the map in the database is not perfect, at least does give you some idea of the locations used.

 

[tvengr]

The Greene County Simulcast 800 site consists of multiple towers placed throughout the county to provide better coverage. They all transmit the same info on the same frequencies at the same time and act as a single site.

 

[W0RS]

Greene county 800 site is one site, what is the other to sites for Springfield/Greene county?

This is the config file but it almost does not look correct due to the extension... Thanks for the help oh nuts, it won't stick...

 

[tvengr]

This is the config file but it almost does not look correct due to the extension... Thanks for the help

I don't see the file. Save your current configuration to archive. Read the scanner and then save that that configuration to archive with a different name. Attach the file you just read from the scanner. That will show me exactly what you have in the scanner. You need to click on Attach files and Open the file to attach it. You don't have to zip the TRX-2 configuration archive file to attach it. The TRX-2 file is already zipped. See if you can attach the file. I will check it tomorrow.

 

[W0RS]

Greene county 800 site is one site, what is the other to sites for Springfield/Greene county?

I don't see the file. Save your current configuration to archive. Read the scanner and then save that that configuration to archive with a different name. Attach the file you just read from the scanner. That will show me exactly what you have in the scanner. You need to click on Attach files and Open the file to attach it. You don't have to zip the TRX-2 configuration archive file to attach it. The TRX-2 file is already zipped. See if you can attach the file. I will check it tomorrow.

I don't see the file. Save your current configuration to archive. Read the scanner and then save that that configuration to archive with a different name. Attach the file you just read from the scanner. That will show me exactly what you have in the scanner. You need to click on Attach files and Open the file to attach it. You don't have to zip the TRX-2 configuration archive file to attach it. The TRX-2 file is already zipped. See if you can attach the file. I will check it tomorrow.

Ok, This is the archived file....

 

[tvengr]

There were not any conventional frequencies or trunked systems in the file. Here is a quick file I did for Greene County. It will scan all 3 sites. Please let me know how it works.
Scan Lists:
1. Fair Grove site
2. Springfield site
3. Greene Co site

 

[W0RS]

There were not any conventional frequencies or trunked systems in the file. Here is a quick file I did for Greene County. It will scan all 3 sites. Please let me know how it works.
Scan Lists:
1. Fair Grove site
2. Springfield site
3. Greene Co site

Ok, I will let you know when I get home. I can't pass a McDonalds don't ya know 🍟🍟

 

[tvengr]

Ok, I will let you know when I get home. I can't pass a McDonalds don't ya know

The file doesn't have any conventional frequencies. It is just to see if using all 3 sites increases the number of talkgroups you are able to monitor.