Problems with Grecom PSR-600 not hearing P25 Talk Groups

[jim202]

Have a Grecom, PSR-600 trying to listen to the Louisiana P25 LWIN trunking system that doesn't seem to want to provide any voice audio.

I am located in Saint Tammany Parish in Folsom, Louisiana. Have tried several different software programs and also different computers with the same results. Think I need some tutoring to resolve the problem. Have read the user manual and tried to follow the different software programs I have tried with no improvement.

It still doesn't seem to want to scan correctly. This is not a new scanner, but one that I was given after my radio mentor passed away.

I have been licensed as a ham radio operator K1VTY since 1962. Worked on Public Safety radio systems for many years. Have my own bench service equipment.

Just need a hand getting pointed in the correct direction on this radio.

Jim202

 

[jaspence]

That series of radios don't usually work well with P25, especially if it is simulcast. The Whistler factory update may improve it, and if phase 2 is being used, it will probably not work. In some situations, a directional antenna will help, but Phase 2 is still likely to not work.

 

[jim202]

This is not phase 2. The nearest tower is only about a mile away, so the simulcast is not a problem.

 

[tvengr]

This is not phase 2. The nearest tower is only about a mile away, so the simulcast is not a problem.

Simulcast can equally be a problem on phase 1 systems. My local Baltimore County simulcast system is phase 1 and the only radios which will receive it are the Uniden SDS100 and SDS200 scanners and the Unication G4 and G5 pagers. All other scanners fail miserably and I have tried them all. The St Tammany Parish site on LWIN shows as simulcast. All law enforcement in the parish is fully encrypted and cannot be received by any scanner. If you are using programming software, please attach your file and I will check it for problems. I have ARC500, Win500, and PSREdit500. You will need to right click on the file and Send to Compressed (zipped) folder to be able to attach it. Click on Attach files and open the zipped folder.

 

[jaspence]

Louisiana Wireless Information Network (LWIN) Trunking System, Statewide, Louisiana Check this link. The scanner does not go down below 796 (RigPix Database - GRE/GRECOM - PSR-600) and it is a simulcast system. All frequencies are well bellow the range of the scanner according to the RR chart. Even though you are close to a tower, a second tower with more power output or elevation could cause distortion.

 

[Whiskey3JMC]

One of the most (perhaps THE) discussed topics on the RR forums

Simulcast Distortion - The RadioReference Wiki

wiki.radioreference.com

 

[ScannerSK]

The scanner does not go down below 796 (RigPix Database - GRE/GRECOM - PSR-600) and it is a simulcast system. All frequencies are well bellow the range of the scanner according to the RR chart.

The above RigPix Database webpage shows the frequencies incorrectly. The PSR-600 scanner also receives from 764.00000-781.99625 and from 791.00000-796.99625. I just verified this with my own PSR-600.

Also, just because the Louisiana Wireless Information Network (LWIN) Trunking System, Statewide, Louisiana contains some simulcast towers does not mean the entire system is simulcast. Out of the 137 towers, only 4 are noted as being simulcast. The remainder of the towers are likely a mix of some simulcast and some non-simulcast towers.

I listen to a simulcast system regularly (Front Range Communications Consortium (FRCC) Trunking System, Weld County, Colorado) with a PSR-600 scanner with only minor issues. I owned an SDS100 for a short time and it suffered as well on my local simulcast system. The Uniden scanners however tend to receive noticeably better on simulcast systems and don't suffer from the severe desense issue discussed below.

One issue the PSR-500/600 scanners suffer from is severe desense (lowered sensitivity) due to out of band signal overload. If you live near communication towers, especially cellphone or television, then this scanner may not be usable.

I would recommend pressing "tune" and then manually entering the control channels (one at a time) to verify you are at least receiving data from the control channel on the scanner. If yes, then the issue is likely just a programming issue. If no, then the scanner may be suffering from reduced sensitivity due to signal overload from nearby communication towers which may make the scanner unusable in that particular location.

Shawn

 

[hiegtx]

The above RigPix Database webpage shows the frequencies incorrectly. The PSR-600 scanner also receives from 764.00000-781.99625 and from 791.00000-796.99625. I just verified this with my own PSR-600.

Also, just because the Louisiana Wireless Information Network (LWIN) Trunking System, Statewide, Louisiana contains some simulcast towers does not mean the entire system is simulcast. Out of the 137 towers, only 4 are noted as being simulcast. The remainder of the towers are likely a mix of some simulcast and some non-simulcast towers.

Shawn

The link to the user manual, on the RigPix page, also leads to misleading information. The base y frequencies specs in the manual show only frequencies above 796.0000 to be valid:

But just above that in the specs, the correct lower frequencies (in the 700Mhz band) show in the details.
Frequency step modes:


And, down below the specs, are the ranges used by Spectrum Sweeper:

So, as Shawn has noted, the frequency range is not an issue.

 

[tvengr]

That series of radios don't usually work well with P25, especially if it is simulcast. The Whistler factory update may improve it, and if phase 2 is being used, it will probably not work. In some situations, a directional antenna will help, but Phase 2 is still likely to not work.

Phase 2 definitely will not work. The PSR-600 is capable of P25 Phase 1 only and cannot be upgraded to Phase 2. The Whistler Legacy Upgrade is for the GRE PSR-800 and for the Radio Shack PRO-18 and PRO-668 only. The upgrade does add P25 Phase 2 to the PRO-18.

 

[jim202]

The LWIN system here in Louisiana is still phase 1. Yes the parish I live in is simulcast, but where I live, there is no problem from other towers. My local tower is less than a mile from me. I can see it through the trees and have almost a full scale on the RF signal level indicator. The next closest tower is over 10 miles away.

I can step through the 4 control channels from the local tower and only hear just one that is active.

There are only 14 talk groups in the scan list. One is our local State Police dispatch in the town south of me that should be reasonbaly active. But I have heard nothing coming out of the scanner so far. I di see the state police talk group showing up on the display about every second. The system ID of LWIN shows up when the talk group is not being displayed. So my guess is it is scanning.

What I am not sure about is it is displaying GA to the left of the signal strength indication. I have not found out the meaning of this yet.

 

[tvengr]

GA means the global attenuator is on. That cuts way down on the receive sensitivity. Press the ATT button on the scanner and the A will go out.

 

[jim202]

Thank you for the info. The signal strength is now showing 5 bars and just the G next to it.

 

[tvengr]

Only one of the control channel capable frequencies can be active at any time. When trying to receive simulcast systems, turning on the attenuator will often improve reception. It can reduce the number of subsites you receive and improve control channel decoding. With the global attenuator off, you can turn on the attenuator for each trunked system if necessary. Each conventional frequency also has the ability to turn the attenuator on and off. Generally, the attenuator should be off for conventional frequencies.

 

[ScannerSK]

Thank you for the info. The signal strength is now showing 5 bars and just the G next to it.

You can make the G (stands for Global) disappear if you press FUNC then ATT.

 

[ScannerSK]

I can step through the 4 control channels from the local tower and only hear just one that is active.

There are only 14 talk groups in the scan list. One is our local State Police dispatch in the town south of me that should be reasonbaly active. But I have heard nothing coming out of the scanner so far. I di see the state police talk group showing up on the display about every second. The system ID of LWIN shows up when the talk group is not being displayed. So my guess is it is scanning.

It appears you are receiving the control channel. As a test, I would try adding what is called a wildcard talkgroup to the active scan list. This will allow you to receive all the traffic occurring on the tower.

Create a new talkgroup by pressing PROG then F1 then F1 a second time. Assign the talkgroup to the active scan list, select the talkgroup system to attach this talkgroup to, leave the ID as Wildcard and leave the Type as Group. That's basically it.

This should allow you to receive all traffic occurring on the system as a test.

Also, when programming the system, most program the system type as P25 Auto. If the system is not set up as P25 Auto this could cause problems.

 

[jim202]

Simulcast can equally be a problem on phase 1 systems. My local Baltimore County simulcast system is phase 1 and the only radios which will receive it are the Uniden SDS100 and SDS200 scanners and the Unication G4 and G5 pagers. All other scanners fail miserably and I have tried them all. The St Tammany Parish site on LWIN shows as simulcast. All law enforcement in the parish is fully encrypted and cannot be received by any scanner. If you are using programming software, please attach your file and I will check it for problems. I have ARC500, Win500, and PSREdit500. You will need to right click on the file and Send to Compressed (zipped) folder to be able to attach it. Click on Attach files and open the zipped folder.

Give me some time to read the program I have and get it to you. Thanks for the offer.

I understand that all the Parish police departments are encoded. Not trying to listen to them. Looking to monitor several of the local fire department and EMS groups, plus the local state police troop L in Covington. All of these are in the clear.

I use to do a bunch of the local public safety radios service work some years back. I do have my own service monitors and like helping the local hams when they are having a problem. Even try to be a mentor to them when they may need some help or guidance.

I have been an active ham since around 1962 if it matters.

 

[tvengr]

There are a few things you can do to minimize the effects of simulcast. I have had better luck with the SuperTrack decoding algorithm enabled. You can try it both on and off. Turn off digital AGC. The AGC action can increase garbled audio problems. Enter only the 4 control channel capable frequencies for the site. If the scanner loses lock on the control channel, it doesn't need to search through all of the voice frequencies to find the control channel again. I assume you have the system type set to P25 Auto. You don't need to worry about trunking tables. I have a Radio Shack PRO-197, the younger brother of your scanner. If Multi-Site is set to Roam, you will receive only the site with the best signal. If set to Stationary, the scanner will scan all sites whose control channels are in the frequency list. If you use only a single site, set Multi-Site to Off.

 

[jim202]

Only one of the control channel capable frequencies can be active at any time. When trying to receive simulcast systems, turning on the attenuator will often improve reception. It can reduce the number of subsites you receive and improve control channel decoding. With the global attenuator off, you can turn on the attenuator for each trunked system if necessary. Each conventional frequency also has the ability to turn the attenuator on and off. Generally, the attenuator should be off for conventional frequencies.

 

[jim202]

Not sure I attached the file to you. It doesn't want to attach correctly.

 

[jim202]

There are a few things you can do to minimize the effects of simulcast. I have had better luck with the SuperTrack decoding algorithm enabled. You can try it both on and off. Turn off digital AGC. The AGC action can increase garbled audio problems. Enter only the 4 control channel capable frequencies for the site. If the scanner loses lock on the control channel, it doesn't need to search through all of the voice frequencies to find the control channel again. I assume you have the system type set to P25 Auto. You don't need to worry about trunking tables. I have a Radio Shack PRO-197, the younger brother of your scanner. If Multi-Site is set to Roam, you will receive only the site with the best signal. If set to Stationary, the scanner will scan all sites whose control channels are in the frequency list. If you use only a single site, set Multi-Site to Off.