P25 Issue after re-banding in Cincinnati/Hamilton County

[beischel]

Hi Group,

I noticed that when the Cincinnati/Hamilton County (Ohio) System rebounded that I started having issue with the P25 audio breaking up at times. It used to be perfect before rebinding. The issue used to happen on my Uniden 996, but decided to give the 996 to my nephew and go with the GRE 500 and 600. The GRE's were much better. Then, rebanding occurred and the GRE's started acting like the Uniden.

When the audio was breaking up, I noticed the the signal strength bars would vary quite a bit at the top going from three to five bars, up and down almost wildly. Of course when they were a solid five, the audio would be just fine.

I tried the attenuator, without any success. Really puzzled me.

So then I decided to experiment. I changed the selection of the Control Channel from Roam to Stationary and that made a huge improvement. My thinking is that maybe it kept changing control channels or something which created the issue with the signal strength meter bouncing around. Now, with the scanner set to stationary for the Control Channel selection, that issue does not seem to happen as much now.

I live within a few miles....maybe even a mile....of two of the transmitter locations for this system. So that is not an issue in terms of being too far.

So anyway, wanted to relay the experimentation in case anyone else having an issue AND wanted to see if anyone else had that issue and what you may have changed to resolve it or improve the audio.

Thanks,

Duffy

 

[beischel]

Wow, I must be the only person who has issues with the P25 audio breaking up.

 

[cpetraglia]

P25 Issues.

You are not the only one. I was unable to get any answers either. I will try your idea and post back. I too am very close to the transmitters and the PD I am trying to listen too.

Chuck

 

[Russell]

It is very common for the rebanded transmitters to use different power levels than the non-rebanded transmitters. The new transmitters tend to be higher power which can overload your radio making it seem like it's missing the signal. Try using less antenna (I've never gotten attenuation to solve this prob). They tend to use higher power and/or more transmitters to solve the building penetration and coverage problems.

On the, other hand, I know of some systems that go to lower power transmitters. In Austin (Travis County) I was less than two miles away from the Williamson County line (adjacent county); when Williamson went to P25 they turned their power down and I could receive absolutely nothing unless I was in that county.

As usual, YMMV, try to determine if the power levels changed; if the power is up then use less antenna, if the power is down then you may need more/better antenna. Yes, it is very frustrating.

Russell

 

[cpetraglia]

It is very common for the rebanded transmitters to use different power levels than the non-rebanded transmitters. The new transmitters tend to be higher power which can overload your radio making it seem like it's missing the signal. Try using less antenna (I've never gotten attenuation to solve this prob). They tend to use higher power and/or more transmitters to solve the building penetration and coverage problems.

On the, other hand, I know of some systems that go to lower power transmitters. In Austin (Travis County) I was less than two miles away from the Williamson County line (adjacent county); when Williamson went to P25 they turned their power down and I could receive absolutely nothing unless I was in that county.

As usual, YMMV, try to determine if the power levels changed; if the power is up then use less antenna, if the power is down then you may need more/better antenna. Yes, it is very frustrating.

Russell

I have gone back to my indoor RD antenna, tried attenuate with the same exact problem. I did notice this morning using two different scanners, the P25 and the MOTO 800 system are both using the same CC frequency. I dont know enough about it, but this seems it may cause problem. When the old system is active, it sounds perfect. When it goes off line, the P25 is about useless no matter what I use for an antenna.

 

[beischel]

I was also thinking overload, except the attenuator does not seem to help it. I have it set to stationary now and also have checked the box on the Starsoft program to tell it to scan all the CC's to find the best one. It's not perfect yet, but it seems to work better 90% of the time. I mean I did a lot of experimenting this weekend with settings, scanner location, etc.

I have two scanners - the 500 and the 600. The 600 is on the second story of the house. So I have collapsed the antenna most of the way down, and tilted it to one side so it is no longer completely vertically polarized. Maybe it is my imagination, but all that seems to work the best.

The 500 in the basement of the house with the Rat Shack 800Mhz duck seems to do slightly better. It will break up at times, but not as bad.

I guess for now, I've got it as good as I can get it.

Duffy

 

[GrumpyAeroGuy]

My experience monitoring Hamilton County is sketchy at best. I too have it set to stationary.

Now, I am north of Hamilton County in Warren County, but not very far north of the Hamilton Warren County Line.

It's touch and go at best for me. I have not had the opportunity to try the scanner well within the county line, however.

Clermont County comes in FAR better from my vantage point. Warren, of course, (analog) works fabulously.

Incidentally, I have friends that are involved with Ham Cnty public safety, and they even will tell you that that system ain't the best even for them using the OEM system equipment.

 

[cpetraglia]

I've been making changes and also monitoring the P25 and 800 sys on seperate scanners. PSR600 for the P25 and BC796D for the 800. They are both using the same control channel freq. at the same time. My county is in the switch over process. After trying PSREdit, I noticed while monitoring a P25 group, the mute indicator goes on and off during a conversation representing the bad reception. I never loose signal strength.
I also used Hyper Terminal to read the CC for the P25 and saw Errors at least 20 times a minute. When looking at another P25 sys in my area, only one or two errors in 5 minutes. I can listen to this system perfectly and they have finished switching over. I am holding my fingers crossed that the issues with Fairfax Co., VA will go away when they are done with the switch over.