[TrunkCom] Trunk-tracking Help

Tue, 19 Mar 2002 14:55:19 -0600

Greetings Scott,
        My only guess is that, for whatever reason (Might be a few),
your trunktrackers are picking up (Private Trunk Comms).  Normally
the 235xlt & 245xlt pickup the 'P' status, and ignore such comms
while in the 'Trunk' Mode.   But, I believe it might be possible for 
our Trunktrackers to receive it as a 'Group' or normal talkgroup 
comms. 

Here in St Louis, Missouri the 'P' status is used for what the Police
Officers call 'SmartLine' comms.  Or Private-Line.  

Of course, on the 780xlt, this 'Private-Line' comms is refered to
as 'I-Call'.

I've noticed this problem with a local Trunk System here in St Louis,
Missouri.  Its the 'America's Center / TWA Dome' system.  (Well,
formerly TWA Dome).

Same problem as yours:  conversations taking place on talkgroup
IDs that are not logically space apart, as to conform to the normal
Type I arrangement.  (Does not fit the Size Code selections available
within the programming of our TrunkTrackers).

With this system, I can not seem to find a way to use a single 
Size Code, that conforms to place same-conversations onto the
same Talkgroup IDs.  In other words, get all of the same comms
onto the same ID groups.

So, I've come to the conclusion that the Trunktracker is Receiving
those comms as a Talkgroup (for whatever reason), though I believe
they are actually suppose to be 'I-Call' comms or Private-Line.

In St Louis, Missouri ; that would be 'SmartLine' comms.

If this is so, I can only speculate as to why our Trunktrackers are
interpretating those 'I-Call' IDs as normal Talkgroup comms.

I should point out, that this problem is only with a few IDs that 
appear within the Block #7 span.  (For the America's Center system).
The remaining talkgroups within Block #7, all conform perfectly
to Type II (All divisable by 16, and the various comms stay on the
evenly divisable-by-16 Type II talkgroups).  

I should also point out, that I have made every effort to eliminate
reception problems as the cause or possible cause of this effect.
It happens no matter how close or how far I am located from the 
Trunk system.  One day, I even resorted to parking my car on
Laclede's Landing, just to the north of the MLK bridge in downtown.
Reception of the America's Center Data Channel was perfect 100%
signal copy.  I even removed the antenna, just to prove that 
reception was not the problem.  The signal strength was still
near 100% copy.  

The problem still continued.  For those that might be interested 
in taking a crack at this very interesting problem on this TRS.
I welcome you to visit St Louis, Missouri and program in the
America's Center / TWA Dome TRS into any Trunktracker
scanner you may own:

- 857.2375
- 857.9375
- 858.7375
- 859-7375
- 860.7375

http://gullfoss2.fcc.gov/cgi-
bin/ws.exe/genmen/uls/call_res.hts?db_id=19&rows=&callsign=WPGU376

or go here, then select 'CALLSIGN', and type in:  WPGU376

http://gullfoss2.fcc.gov/cgi-bin/ws.exe/genmen/index.hts

It is basically a Motorola Type II system, with those noted issues 
listed above.  Blocks used:

Block #0
Block #6
Block #7

Block #7 is the one that has the problem talkgroups.
Most of the talkgroups in Block #7 behave correctly.
Its only a select few that have this issue.

I invite your comments if you choose to take on this
unique situation.  I believe this problem is not really wide
spread.  But based on the last post to Trunkcom, obviously,
the problem is not a St Louis, Missouri ONLY problem.

I welcome your comments, if, you choose to try it.

73...

On 19 Mar 2002 at 3:42, Scott Baldwin wrote:

> Hello to the list.
> 
> I'm trying to set up my BC-245 and BC-895 to track the trunking system at 
> the Vacaville CMF Prison site.  Their frequencies are 857-860.2625.
> 
> I started off in E2 mode, and noticed the ID's changed between radio 
> users.  So I assume it to be a Type-1 system.  Setting it in E1 Mode, I 
> chose S-14 as my size.  Even though this is an unusual size, I chose it 
> because I had caught traffic with an ID of 37217 and the reply came back on 
> 34135.
> 
> Using the method of lowest ID and highest ID, the difference is 3082, 
> meaning at least THAT many users used block 4.  Since S-13 has a max of 
> 2048 users, and S-14 is the next with 4096 users, for this reason I chose S-14.
> 
> Now here's my problem.  I was monitoring the other day and a call came out 
> with an ID of 000-9 and a reply came back on 000-8.  It was the same 
> conversation.  My BC-245 was still set on E2, and I noted ID 38374 and 
> 34267, respectively.  The problem as you can see is that the number of IDS 
> (difference between the two) is 4107.  This exceeds the max of 4096 as used 
> for a Type 1.
> 
> Does anyone know what kind of system this is, if it's not Type-1 or 
> Type-2?  I have tried Edacs and LTR, but I either don't know how to set 
> these systems up in my scanner, or they're not that either, as I've tried 
> programming them in, but they don't track at all.  It's as if they don't 
> see the control channel.
> 
> Thanks in advance.
> Scott
> N6UUH

73 from todd hartzel / n0vkg
http://www.icon-stl.net/~toddh