P25 Showing Full Signal, No Audio

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ryned1

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I’ve just kind of gotten back into scanning, but have never had a trunk tracking scanner. Recently I’ve purchased a BCD536HP and am mostly liking it. (Although I didnt realize till now that the SDS100/200 were the better option until now.)

Anyway, Im receiving all conventional frequencies (digital & analog) loud and clear. However, I have not been able to pick up any sort of audio from a p25 trunked system even though it’s showing full signal bars that it’s picking up the site.

The primary system I was trying to monitor is Midland (P25). Based on what I’ve read/researched. Midland is simulcast, so I chalked it up to maybe that was the issue and kind of wrote it off and stopped trying to monitor it. I might mention that I also thought distance could be an issue as I was trying to monitor on the fringes of the system. I did go mobile once and got a lot closer (within 5 miles of site) and still nothing.

So I travel a lot and I thought I would bring it to San Angelo and try to monitor the San Angelo (P25) system. From what I can tell San Angelo is not simulcast so that shouldn’t be the problem. I am only expecting to hear fire because police is fully encrypted. I am within 5 miles base trying to monitor this system. Again showing full signal bars but not catching any audio.

It feels as if I’m missing a setting somewhere. The scanner has been updated and set up through sentinel. Including fav list and assigning quick keys. The correct services are turned on. I have even tried using the zip code function
 

hiegtx

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I’ve just kind of gotten back into scanning, but have never had a trunk tracking scanner. Recently I’ve purchased a BCD536HP and am mostly liking it. (Although I didnt realize till now that the SDS100/200 were the better option until now.)

Anyway, Im receiving all conventional frequencies (digital & analog) loud and clear. However, I have not been able to pick up any sort of audio from a p25 trunked system even though it’s showing full signal bars that it’s picking up the site.

The primary system I was trying to monitor is Midland (P25). Based on what I’ve read/researched. Midland is simulcast, so I chalked it up to maybe that was the issue and kind of wrote it off and stopped trying to monitor it. I might mention that I also thought distance could be an issue as I was trying to monitor on the fringes of the system. I did go mobile once and got a lot closer (within 5 miles of site) and still nothing.

So I travel a lot and I thought I would bring it to San Angelo and try to monitor the San Angelo (P25) system. From what I can tell San Angelo is not simulcast so that shouldn’t be the problem. I am only expecting to hear fire because police is fully encrypted. I am within 5 miles base trying to monitor this system. Again showing full signal bars but not catching any audio.

It feels as if I’m missing a setting somewhere. The scanner has been updated and set up through sentinel. Including fav list and assigning quick keys. The correct services are turned on. I have even tried using the zip code function
While it's not flagged that way in the database, the San Angelo system also appears to simulcast.
1656707001462.png
The 'Location 5' (not on the map)is for a fixed location using the input frequencies for the system, like a dispatch center. Location 4 is a reference point for mobile (field) units. But the other three are simulcast of the system frequencies.

However, looking at licensing for San Angelo, I see a second license, also with system frequencies.

That adds some additional towers:
1656707563920.png

Again, location 4 on the map is a reference point for mobile units.

If simulcast is present (and it appears to be), then your scanner could very well show full bars (strong signal) but not actually decode correctly & generate the audio of conversations.

As for Midland, it's not specified as Simulcast in the database, but like the San Angelo system, it only shows one license that generates a site map: FCC Callsign WNSS433 (CITY OF MIDLAND TX)
1656708811401.png

But, as with the San Angelo system, there are additional licenses, with additional tower locations:

1656709081357.png
Ignore location 7; that's a control point.

1656709443986.png
Location 1 is at the same address as Location 1 on license WQVX311.

I did go mobile once and got a lot closer (within 5 miles of site) and still nothing.
You would need to be closer than 5 miles, Preferably less than a mile (a quarter mile would be even better.

Your possible options in trying to deal with Simulcast include using a directional antenna aimed at one specific tower, possibly making the scanner ignore the other signals. Using 'less' antenna, including even a paper clip. Maybe using the attenuator. Move the scanner around in your house, to see if there is a 'sweet spot' where it will work. In some cases, placing a baking pan or cookie sheet next to the scanner (using it's antenna, not an external one) to block out signals from a different location, None of these are practical in mobile operation when you're out & about (unless the attenuator does the job, but that's rarely the case), and in some cases, none of the suggestions work.

The Uniden SDS100 & SDS200 scanners were designed to handle simulcast. The Unication pager & the Blue Tail receiver can handle simulcast, but have limitations as opped to what the SDS series scanners can do. For listening from home, you could also get one of the SDR dongles, & using software that you can download, along with your PC to deal with the issue.

More on Simulcast in the Wiki (if you haven't already seen it).
Simulcast digital distortion - The RadioReference Wiki
 

ryned1

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Joined
Dec 14, 2016
Messages
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While it's not flagged that way in the database, the San Angelo system also appears to simulcast.
View attachment 123698
The 'Location 5' (not on the map)is for a fixed location using the input frequencies for the system, like a dispatch center. Location 4 is a reference point for mobile (field) units. But the other three are simulcast of the system frequencies.

However, looking at licensing for San Angelo, I see a second license, also with system frequencies.

That adds some additional towers:
View attachment 123699

Again, location 4 on the map is a reference point for mobile units.

If simulcast is present (and it appears to be), then your scanner could very well show full bars (strong signal) but not actually decode correctly & generate the audio of conversations.

As for Midland, it's not specified as Simulcast in the database, but like the San Angelo system, it only shows one license that generates a site map: FCC Callsign WNSS433 (CITY OF MIDLAND TX)
View attachment 123701

But, as with the San Angelo system, there are additional licenses, with additional tower locations:

View attachment 123702
Ignore location 7; that's a control point.

View attachment 123703
Location 1 is at the same address as Location 1 on license WQVX311.


You would need to be closer than 5 miles, Preferably less than a mile (a quarter mile would be even better.

Your possible options in trying to deal with Simulcast include using a directional antenna aimed at one specific tower, possibly making the scanner ignore the other signals. Using 'less' antenna, including even a paper clip. Maybe using the attenuator. Move the scanner around in your house, to see if there is a 'sweet spot' where it will work. In some cases, placing a baking pan or cookie sheet next to the scanner (using it's antenna, not an external one) to block out signals from a different location, None of these are practical in mobile operation when you're out & about (unless the attenuator does the job, but that's rarely the case), and in some cases, none of the suggestions work.

The Uniden SDS100 & SDS200 scanners were designed to handle simulcast. The Unication pager & the Blue Tail receiver can handle simulcast, but have limitations as opped to what the SDS series scanners can do. For listening from home, you could also get one of the SDR dongles, & using software that you can download, along with your PC to deal with the issue.

More on Simulcast in the Wiki (if you haven't already seen it).
Simulcast digital distortion - The RadioReference Wiki
Thanks for the response and in-depth explanation of what is probably going on. Fortunately, I am content knowing that it’s probably the the scanners capabilities(Incapabilities) that is the problem rather than something I may be doing wrong. Home base for me sits perfectly in an four county rural area that I can monitor all p25/non p25 VHF coventional no problem and that’s all I was really hoping for at the moment.
 
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