Poplar Bluff PD/FD New System

[wb0wao]

Site 3 was solid copy all day here- running around 400 consistently. I was hearing both sides of the conversation. I logged 44 different UID's today. I don't think that the system is fully configured yet - I was getting some "oddities" with the UID's. I would get the organic UID's 1xxx and 2xxx numbers sometimes and then sometimes I would also get the display of Unit xxx - but on one instance it displayed the actual DSN number of the officer - 2304 - and their last name! The only UID's that I have programmed into the scanner is the UID for the PBPD and EMS dispatch.

As for the EMS units, I am getting nothing from the EMS units as to UID. I am hearing both sides there too, and I didn't hear anything on the VHF frequency today. Going up to Bluff in the morning and will listen on the VHF EMS channel to see if they are still operating there.

Since each of the three sites are using different frequencies, even monitoring one site should provide everything on the network. Since none of the frequencies are reused, it isn't a simulcast system. And you would want the units all over the city to be able to hear what everyone else is saying regardless of where they are at. I could be wrong about this, but I think it is 3 discrete trunk systems that are linked via IP and or microwave as there are a couple of dishes on the tower at the PBPD - one pointing towards the VA and the other towards Briggs & Stratton where the other site is on that one water tower.

 

[dgholson]

As for EMS and Fire Department, I believe that they are being simulcast to the PD's system... I can hear both agencies on their own systems all the time. Also, I'm beginning to think that Sites 2 and 3 are acting as extender's (for lack of a better description) for Site 1... From where if listen from, just north of the city limits, I hear about 90% of their traffic, all from Site 1... There seems to be a drop off every now and then, but no more that I get monitoring MOSWIN channels.

 

[wb0wao]

I agree - I hear EMS on the legacy VHF channel and about 1 second later hear it on the city system. The big indicator for that is that the only UID being transmitted is i2997 and that is for both the dispatch as well as any and all of the EMS units. So TG 110 is just a feed from 152.405. That may also explain why the audio is sub-par.

I haven't heard any FD traffic yet other than a few logged hits.

From the home QTH all I can get is Site 3 but this morning I took my neighbor up for a Dr. appointment and was up there for about an hour and a half. I waited in the car and was able to copy all three sites with 4+ bars on each. I spent a good deal of time flipping back from site to site as I programmed in three separate systems - one for each of the sites. In the 90 minutes I did this, the same traffic was on each system. IMHO, what they have set up is a linked network of three distinct separate sites into a single system. Any traffic that comes in on one site is sent to the other two sites as well. Bottom line is that if you can copy a single site, you will hear everything that is on the system.

Gonna spend the next couple of days doing system analysis of it and see if I can get a good read on what is what.

 

[dgholson]

Then, with that in mind, it would seem that all one would have to do is load the nearest site and not bother scanning the other two. Correct?

 

[wb0wao]

Then, with that in mind, it would seem that all one would have to do is load the nearest site and not bother scanning the other two. Correct?

Pretty sure that would be correct. Have you noticed the significant amount of ancillary data that is coming across with the UID? Not only the traditional UID but a "Unit xxx" and sometimes the DSN and officers last name?

 

[dgholson]

I have on my 436, but not on my 536.

 

[dgholson]

I set Sites 2 and 3 to avoid and I still hear PBPD, so that is confirmed.... Also, I changed my display options on my 536 and now I see the UID info.

 

[RF23]

Site 3 was solid copy all day here- running around 400 consistently. I was hearing both sides of the conversation. ...

Since each of the three sites are using different frequencies, even monitoring one site should provide everything on the network. Since none of the frequencies are reused, it isn't a simulcast system. And you would want the units all over the city to be able to hear what everyone else is saying regardless of where they are at. I could be wrong about this, but I think it is 3 discrete trunk systems that are linked via IP and or microwave as there are a couple of dishes on the tower at the PBPD - one pointing towards the VA and the other towards Briggs & Stratton where the other site is on that one water tower.

When I read this, I realized the problem was at my end & rebooted the scanner; it fixed the problem. Soon I started getting transmissions from all 3 sites.

I expected to get all three sites because I would use ProScan to record for five days and at the end of each day I would copy the results for that day and paste it into an Excel spread sheet. I found that I was getting a distribution (numbert of transmissions per site) of approximately 1/3 for each site, give or take 2%. Earlier in the month when there were only two sites i would get approximately 50-50% distribution of site 1 & Site 2 transmissions during those five days. However, as before most of the time the site the transmission came in on will be answered on a different site. I think this is the cause of the distribution I found. If you are only receiving ONE site, then the info sent to it is also answered there too.

I ASSUMED the control channels were moving me to follow the data being transmitted. I did not know and still don't.



My experiment yesterday of listening to just one Site to see if I was missing anything stopped in about 2 hours when I realized this was not showing me what was on the other two sites, it could be the same or different NO way to tell.

At present, the only way I can see we can be sure if all three sites are broadcasting the same info is to listen to all three at the same time. ProScan cannot tell what is being said, so if you get three transmissions at about the same time unless you hear them you cannot be for sure they are the same data.

 

[RF23]

As for EMS and Fire Department, I believe that they are being simulcast to the PD's system... I can hear both agencies on their own systems all the time. Also, I'm beginning to think that Sites 2 and 3 are acting as extender's (for lack of a better description) for Site 1... From where if listen from, just north of the city limits, I hear about 90% of their traffic, all from Site 1... There seems to be a drop off every now and then, but no more that I get monitoring MOSWIN channels.

I agree, but for how long is this Kind of Simulcast going to last. I expected eventually both EMS and PBPD to totally migrate to the new system.

At first, I thought the distorted EMS dispatch was multi-path distortion but when I use my SDS scanners it sounds just as bad, therefore, it is not that. I think now it sounds more like a phone on the internet without sufficient bandwidth.

Looks like interesting time ahead!

 

[crippledchicken]

Are the new sites in the database for Sentinel? or do they have to manually entered by hand? I hope not, I'm not too good manually. Wonder if they are going encrypted.

 

[crippledchicken]

I tried to unzip the file in post 34 I think, but it would't work? says it's empty?

 

[wb0wao]

I set Sites 2 and 3 to avoid and I still hear PBPD, so that is confirmed.... Also, I changed my display options on my 536 and now I see the UID info.

I have been doing analysis most of the day today and still working on it tonight. I think I have discovered a couple of tidbits so far. However, this is preliminary.

a) 1xxx series UID's I think are portable radios while the 2xxx series UID's are base/mobile radios.
b) The 1xxx series radios send an ID with the officers DSN and last name. It takes about 2 - 3 seconds of straight TX time for these to display on my scanner.
c) The 2xxx series radios send an ID "Unit xxx". I have not seen any DSN/Name come up on 2xxx series UIG radios. Same time delay as in B) above.

I base this on the fact that I have seen the same 2xxx series radio be used by different officers at different times. And the 1xxx series radios are only being used by the officer that is coming up on the scanner - the DSN being used on the air is the same as is displayed.

Going to be working on this system for a while, but having a blast doing it!

 

[wb0wao]

The way to verify the "one site gives everything" hypothesis is to lock onto one site and just listen for the locations of the units running traffic or where calls are being dispatched too as well as the traffic from those calls. If you are hearing a unit doing a traffic stop at MO-53 and Shelby, and you are listening to the VA site - you have your answer.

Note: that only applies to PBPD traffic - EMS/Fire for now is an audio feed from their systems.

 

[crippledchicken]

I'm still trying to enter the frequencies not much luck.

 

[RF23]

I tried to unzip the file in post 34 I think, but it would't work? says it's empty?

It is not a zip file, just remove the .zip from the name and you have an .hpe file that Sentinel can import. This will give you a new favorites for PB NXDN Trunking System. Everything has been entered for you.

 

[crippledchicken]

I'll give it a try

 

[crippledchicken]

I might have got it I'll try programming it

 

[crippledchicken]

I've got it scanning, I'll see what happens. Thanks for your help fellas!

 

[RF23]

The way to verify the "one site gives everything" hypothesis is to lock onto one site and just listen for the locations of the units running traffic or where calls are being dispatched too as well as the traffic from those calls. If you are hearing a unit doing a traffic stop at MO-53 and Shelby, and you are listening to the VA site - you have your answer.

Note: that only applies to PBPD traffic - EMS/Fire for now is an audio feed from their systems.

This is interesting, but you seem to be describing a "Voter or Location based" trunking system. The towers are all linked and the tower that receives you the best will be used first. If all channels are busy on that towr then the master controller will go to the tower that picked you up second best. This should result in towers with very different traffic. It seems to me If all sites are carrying the same traffic it will not matter which tower you are listing to or where the units are located in the city. I have been told that a single tower in a digital trunking systems can send out different info to two cars parked next to each other. I will keep thinking about it, I must be missing something but thank you for the help..

 

[RF23]

Here is the FCC web site for the PB NXDN Trunked System.

Click on the MAP button next to the blue Frequency button top middle of the page to see the theroretical overlap of the three towers (Sites 1, 2, & 3) coverage. This "map" assumes the VA is the mid-town tower, it may be the Haper Street Water Tank instead.

You can access a lot of info on the PB NXDN system from this page. Thnigs like how much RF power the cars, handhelds, & repeters are running, Height of the towers & how many of each radio has been asked for etc.

ULS License - PubSafty/SpecEmer/PubSaftyNtlPlan,806-817/851-862MHz,Conv License - WSAJ269 - POPLAR BLUFF, CITY OF - Frequencies Summary