PSR500 decoding P25 issue?

[SlipNutz15]

I'm not sure if it's an issue with the scanner or the system that it's not completed but here's the situation.

When the console transmits on a Talkgroup the scanner does not decode the transmission unless there is a radio (mobile/portable) selected on that channel somewhere on the system.

Ex. Console transmits on Talkgroup A but there is no activity on the scanner (also unitrunker and Pro26 software) will not decode anything. A portable is turned on and switched to Talkgroup A and the scanner immediately decodes when someone keys up.

Is this a control channel decoding issue or is there another issue I need to look into?

 

[talkpair]

What you are describing sounds like a multi-site system.

In order for a talk group to be heard, a radio on that talk group must be affiliated with the site you are trying to receive.

This type of system is very common for agencies that cover a large geographical area. Transmissions are only broadcast on the sites where there are radios affiliated. Talk groups in rural areas may seem to go completely at times, then suddenly come to life once a radio drives into the coverage area.
This minimizes the number of frequencies required for each site by only sending the broadcast to the areas where it needs to go.

The control channel for a site will not give any clues about transmissions occurring on other sites.

One possible solution is to monitor a site that is more likely to have affiliated radios, such as a populated area.

 

[Ensnared]

P25 Decoding PSR 500

I'm not sure if it's an issue with the scanner or the system that it's not completed but here's the situation.

When the console transmits on a Talkgroup the scanner does not decode the transmission unless there is a radio (mobile/portable) selected on that channel somewhere on the system.

Ex. Console transmits on Talkgroup A but there is no activity on the scanner (also unitrunker and Pro26 software) will not decode anything. A portable is turned on and switched to Talkgroup A and the scanner immediately decodes when someone keys up.

Is this a control channel decoding issue or is there another issue I need to look into?

I received an email from an insider at GRE prior to their departure from the scanner scene. If you are talking about decoding VHF P25 trunking, this radio wasn't designed to work with such. Are you listening to a VHF system?

 

[SlipNutz15]

This is in reference to a 800Mhz P25 Digital Trunked System.

So there has to be a user logged on to the system that has that talk group in their radio and scanning in order for a scanner to pick up the transmission? Or basically the controller knows there is no one on the system that can monitor that talk group and does not transmit on it even though the console appears to be transmitting?

 

[Ensnared]

Information Needed

This is in reference to a 800Mhz P25 Digital Trunked System.

So there has to be a user logged on to the system that has that talk group in their radio and scanning in order for a scanner to pick up the transmission?

Which P25 trunking system are you making reference to in your post. Let me examine such and see if I can help you out.

When I've wanted to decode various P25 trunking systems, I have successfully used Pro96Com & Unitrunker. I have no experience decoding large statewide systems.

 

[SlipNutz15]

Centre County, PA. P25.

When the console keys up the PSR500 immediately decodes talk groups that are currently selected not the portable. Pro96Com and Unitrunker work fine. I've used them both and both decode successfully as long as the portable is on.

 

[GTR8000]

This is in reference to a 800Mhz P25 Digital Trunked System.

So there has to be a user logged on to the system that has that talk group in their radio and scanning in order for a scanner to pick up the transmission? Or basically the controller knows there is no one on the system that can monitor that talk group and does not transmit on it even though the console appears to be transmitting?

If I'm understanding your question correctly: You are aware that someone is keying up the MCC 7500 console on a talkgroup, but you get no audio on the scanner when they do so. However, once a subscriber unit (radio) affiliates with that talkgroup, you begin to hear the console transmitting on the scanner.

If that is correct, then that is normal behavior for a Motorola ASTRO 25 system, and is not a scanner issue. In order for the system consoles to actually transmit anything over the air, at least one subscriber unit must be affiliated with that particular talkgroup. If the zone controller sees no subscriber units affiliated with the talkgroup the console is keying up on, then it doesn't actually transmit over the air at all. Likewise, Unitrunker/Pro96Com will not show any activity because the zone controller is not broadcasting a call over the control channel.

All normal behavior.

 

[SlipNutz15]

Perfect. Thank you. That's what I wanted to know!

 

[captaincook]

I have a psr 500 our county in Mi rebanded. How do I make my radio work again? I checked the freq on rr database and they are the same that I have program in. Conv works for marine.I need to change something in the radio but don't know what to change. I've down loaded the newest frimware. Any help. Thanks. Ed

 

[Swipesy]

I have a psr 500 our county in Mi rebanded. How do I make my radio work again? I checked the freq on rr database and they are the same that I have program in. Conv works for marine.I need to change something in the radio but don't know what to change. I've down loaded the newest frimware. Any help. Thanks. Ed

If you are using Win500 or PSREdit to program your scanner you need to select the reband option -

Win500 - Highlight System and click on Trunking Tables Tab and select appropriate reband.

PSREdit - Select System, click on Edit, click on Rebanding.

That should do it for you.