Bedford County Va new Harris P25 issues and 436

FirstsargeGeri · Nov 2, 2017

Anyone else having issues with the Harris P25 II system in Bedford County, Va and the BCD436?. Everyone around here is complaining that the 436 seems not to be able to handle the new system. I noticed on mine that sometimes it picks up well and most times it is deaf to the system, even when connected to the outside antenna at home. My 996P2 does not seem to have any issues with it. Could it be that the Harris system does not use just one control channel and the 436 can't figure that out? I have all the frequencies programmed in.

troymail · Nov 2, 2017

These systems only use one frequency at any given time for the control channel.

It's hard to believe that the 996 does better than the 436 (even though I know even the 436 still has difficulty - like most all scanners - with simulcast system reception).

Having said that - I'm certain there is something "different" about Harris systems that causes some of my radios (specifically my PSR-500) to not be able to properly process the control channel (I know it doesn't handle Phase 2 voice).

Back to your 996 and 436 - are they both using the latest firmware? Are both programmed the same (either only the Bedford site or all sites and frequencies)? Antenna(s) being used? Location (not just 'at this address but also 'in this exact position' in that location)?

FWIW- I routinely see the 436 'skip over' P25 activity (based on other radios actively receiving it) if/when the 436 has multiple systems, sites, and other things programmed. The 436 will display it is currently 'checking' the system(s) and just keep going without stopping on active talkgroups. It seems that if you increase the time the 436 is allowed to "check" the P25 system in these scenarios (i.e. increase the system HOLD time from 0 to something higher), it is more likely to "eventually" find something. Of course, in doing this you will obviously negatively impact anything else you might be trying to scan.

One last thing -- is there any chance you have any type of location control enabled for the 436? Many times I find myself thinking the 436 isn't working correctly only to remember that I (sometimes) have location control enabled and some of the location data for some systems is either set to really bad limits (combined with some stupid limits applied by the scanner's location algorithms) and/or is that information is just 'bad' or even in some cases 'missing'. Note: I did just check and the site and 'department' location data seems to be fine (more or less) in the RRDB.

Just throwing some ideas out there....

jim202 · Nov 2, 2017

Let me start by saying that on all trunking systems, the control channel is constantly sending out data to the extent of what radio traffic is present. If you have set up your scanner to listen to multiple control channels that are active, I don't want to hear any further complaints. You have basically rendered your scanner to be confused and you will probably never be able to listen to the active traffic.

It takes a finite amount of time to get the scanner to sync into the data flow from the control channel that is broadcasting the radio traffic information. There is a bunch of information that is constantly being sent. Not only are you receiving the site ID, the system ID, but all the requests for a voice channel for those talk groups that are trying to talk.

The system sends out the talk group ID to basically wake up all the radios with that talkgroup number and then tells them to switch to a voice channel. Once there, the user radio will be able to listen to the voice traffic. Be it in the clear or encrypted.

So if your scanner is not listening long enough to the control channel to be able to decode a talkgroup you are programmed to listen to, you will never hear the talk group traffic. The way the trunking system functions is simple enough. But your scanner needs some help in the time your allowing it to stay on the control channel. If your forcing your scanner to listen to multiple trunking systems, you probably will never hear anything as your forcing the scanner to leave one control channel and jump to the next.

Slow down and think for a little bit about just what your trying to do. Trying to listen to multiple trunking systems with a single scanner is never going to make you happy with what your actually hearing. I would rather hear a complete series of transmissions and be able to understand just what is going on. But if you insist on scanning multiple systems, then you will get one transmission from one system and the next transmission from another system. What you hear is total non cohesive junk. One transmission my say something about an accident at a location. The next transmission you hear may be about the officer is doing a DUI traffic stop.

Have fun with your scanning. Just figured I would throw out a few comments about the good and the bad about scanning trunking systems.

troymail · Nov 2, 2017

jim202 said:
Let me start by saying that on all trunking systems, the control channel is constantly sending out data to the extent of what radio traffic is present. If you have set up your scanner to listen to multiple control channels that are active, I don't want to hear any further complaints. You have basically rendered your scanner to be confused and you will probably never be able to listen to the active traffic.

It takes a finite amount of time to get the scanner to sync into the data flow from the control channel that is broadcasting the radio traffic information. There is a bunch of information that is constantly being sent. Not only are you receiving the site ID, the system ID, but all the requests for a voice channel for those talk groups that are trying to talk.

The system sends out the talk group ID to basically wake up all the radios with that talkgroup number and then tells them to switch to a voice channel. Once there, the user radio will be able to listen to the voice traffic. Be it in the clear or encrypted.

So if your scanner is not listening long enough to the control channel to be able to decode a talkgroup you are programmed to listen to, you will never hear the talk group traffic. The way the trunking system functions is simple enough. But your scanner needs some help in the time your allowing it to stay on the control channel. If your forcing your scanner to listen to multiple trunking systems, you probably will never hear anything as your forcing the scanner to leave one control channel and jump to the next.

Slow down and think for a little bit about just what your trying to do. Trying to listen to multiple trunking systems with a single scanner is never going to make you happy with what your actually hearing. I would rather hear a complete series of transmissions and be able to understand just what is going on. But if you insist on scanning multiple systems, then you will get one transmission from one system and the next transmission from another system. What you hear is total non cohesive junk. One transmission my say something about an accident at a location. The next transmission you hear may be about the officer is doing a DUI traffic stop.

Have fun with your scanning. Just figured I would throw out a few comments about the good and the bad about scanning trunking systems.

I concur with just about all of this - with a few exceptions. Key being that Uniden opts to set the system HOLD time to 0 - which in their position means "check the control channel only long enough to determine if talkgroups of interest are active". Clearly, probably mostly in the case of simulcast P25 systems, this does not work very well given I can be actively listneing to a voice call on another radio and the Uniden "scans right past" and never stops on that voice call.

You are absolutely going to miss transmissions if/when scanning large numbers of systems and channels and even when enabling many talkgroups on a system and they are active. You are absolutely going to miss transmissions if/when you are scanning the "full database" and using location control (way too much junk being scanned in this mode even with a range of 0).

When trying to understand why one radio isn't picking up activity that another radio is receiving, you really need to drop down to singular systems/sites/control channels and in some cases, even single talkgroups, if you want to do side-by-side troubleshooting and comparisons.

FirstsargeGeri · Nov 2, 2017

Reply to Troy mail and Jim202

Yea the 996 actually seems to be better all around than the 436 and 536. I have all scanners programmed the same for that system (although I did experiment with different settings to see if that makes any difference, ie threshold hold limits, hold times etc.) and there was no change.

I use the same outside antenna as a benchmark, first I would scan with 996 and get a lot of hits, then I would switch the antenna to the 436 and get nothing.

All scanners are running the latest firmware and none have any locations or priorities activated and sitting right next to each other when I run comparisons. I also have the 325P2 and the 1080 which seem to do a better job.
I must say that I am a little disappointed with the 436 and the 536, but more with 436. You would think with price tag those scanners carry they would have no problems handling that system.

I have a Unication that handles the Bedford system with no problem.

Jim202 - The Harris P25 actually uses multiple control channels and can change which one they use at any time. They cold use one channel in the morning and another in the afternoon. You have to have all the frequencies loaded when scanning a Harris system and I think that is where the problem lies with 436. The 996P2 seems no to care about it.

FirstsargeGeri · Nov 2, 2017

I don't think your understanding what I am trying to say or probably I'm not saying it right. Check out the Bedford System in RR to see the layout.
Even if I only have that one system active, the 996 will pick up mor traffic than the 436 which just sits there and scans away. I know that the more you loaded the more your gonna miss, (been scannerhead for over 40 years), but in comparing the 436 to several other scanner models, the 436 really seems to have a problem. You have to have all the channels loaded when monitoring a Harris P25 system because of the way it works, The Harris system can and does change CC's randomly at any given time, sometimes more than once in a day, if you don't have all the frequencies loaded then you will surely miss a lot.

KevinC · Nov 2, 2017

Moved to Virginia forum as this is not a database issue.

troymail · Nov 2, 2017

FirstsargeGeri said:
I don't think your understanding what I am trying to say or probably I'm not saying it right. Check out the Bedford System in RR to see the layout.
Even if I only have that one system active, the 996 will pick up mor traffic than the 436 which just sits there and scans away. I know that the more you loaded the more your gonna miss, (been scannerhead for over 40 years), but in comparing the 436 to several other scanner models, the 436 really seems to have a problem. You have to have all the channels loaded when monitoring a Harris P25 system because of the way it works, The Harris system can and does change CC's randomly at any given time, sometimes more than once in a day, if you don't have all the frequencies loaded then you will surely miss a lot.

FirstsargeGeri said:
Jim202 - The Harris P25 actually uses multiple control channels and can change which one they use at any time. They cold use one channel in the morning and another in the afternoon. You have to have all the frequencies loaded when scanning a Harris system and I think that is where the problem lies with 436. The 996P2 seems no to care about it.

The rotating of the control channel over multiple frequencies isn't all that unusual. However, to be clear (and I'm sure you know), at any given moment in time, each site of a system will only being using one frequency as control.

There are some systems - Harris types being one - that seem to want to use all of the frequencies as control channels over time (daily/hourly or other event driven change). That isn't unusual. For any scanner, you'll need to load all of the frequencies on these types of systems or run the risk of the radio going silent (assuming it is working at all). I noticed that for this system, each of the sites is only listing a single control channel and not even a single "alternate". That needs to be addressed for those who use the option of loading only the control channel frequencies.

As far as the 436 -- it almost sounds like it may have some other type of problem. Does it receive any other P25 systems?

kb4cvn · Nov 3, 2017

Harris Systems, going back to the EDACS Systems in the GE and Ericsson eras, can use ANY frequency pair as a control channel. Rotating the control channel on a regular basis is considered a good management practice, as it spreads out the 'wear and tear' on the system components over several repeater stations, rather than just one or two repeater stations. It lowers the MTBF (mean time between failures).

Motorola for some reason never did this, and usually only confined their control channels to the first few channels in a frequency set.
Limitation of their technology? ...I don't know.

I can speak on Harris systems, as I designed and installed them...

In a P-25 system (and older EDACS too), there will only ever be a single control channel at a time.
It does not matter if it is a single site system, or a 20 site simulcast cell!

Trying to scan across several systems and control channels is flawed from the start. At 9600 baud data rates, the WORKING CHANNEL ASSIGNMENT message to user radios is on average only 30 milliseconds in length. Miss it, and you have to wait for the message to be repeated on the control channel, at which time you late-enter into the group call.

The only reliable method to listen to several trunked systems, REGARDLESS OF THE TECHNOLOGY FORMAT (EDACS, LTR, Moto, TETRA, MPT-1327, etc.), is to have multiple scanners listening to the systems, one dedicated to each system.

My humble 2¢ worth....

jim202 · Nov 3, 2017

FirstsargeGeri said:
Jim202 - The Harris P25 actually uses multiple control channels and can change which one they use at any time. They cold use one channel in the morning and another in the afternoon. You have to have all the frequencies loaded when scanning a Harris system and I think that is where the problem lies with 436. The 996P2 seems no to care about it.

I may have miss led you in saying that there was only one control channel. What I should have said was that only one control channel is active at any given point in time. In a simulcast system, all sites will use the same control channel unless there is a failure at one of the sites. then the system will make a system wide change to another control channel.

Yes the channels do change now and then. Some systems change the channel daily and others don't change the control channel unless there is a failure of the primary control channel. This is the way all trunking systems function.

bedrock · Mar 20, 2018

Was wondering if anyone else that monitors CVRCS Bedford Town and Bedford County is having issues with radio receive volumes..using a G4 and G5 for monitoring and about 40% of the transmissions are coming in with weak (low) volume. If I turn the radio up a little, the louder transmissions will be way too loud. Would like some input if appropriate.

kb4cvn · Mar 21, 2018

bedrock said:
Was wondering if anyone else that monitors CVRCS Bedford Town and Bedford County is having issues with radio receive volumes..using a G4 and G5 for monitoring and about 40% of the transmissions are coming in with weak (low) volume. If I turn the radio up a little, the louder transmissions will be way too loud. Would like some input if appropriate.

It is usually an issue in the programming of the radio. There is a microphone AGC level setting in the options of the radio, which is different for mobile and portable radios.

Far too often, the person programming the radio fails to understand the significance of this setting. The personality will have been written for a portable (0 dB gain) and then also gets dumped into a mobile, which requires the 12 dB gain setting, and therefore sounds low/weak with the incorrect 0 dB setting.

The person not understanding what they are doing also explains why there are so many radios with the exact same Logical ID number, especially Law Enforcement radios!

bedrock · Mar 22, 2018

Thank you for the info....

Bedford County Va new Harris P25 issues and 436

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