Help with Los Angeles basin LTR systems

[LAflyer]

Hello everyone,

Over the last couple months have received several submissions for random LTR frequencies noted in the Los Angeles basin.

I have managed to successfully match up several of these with existing systems in the Db but have a bunch left over still.

I was also able to run UniTrunker on several and help map out what the systems likely look like. Below are my findings.

I would be grateful if anyone has the time or interest to help tie up these system.

Unknown # 1
8 -
12 - 472.4625
20 -
Noted TG:
0-12-132 - KTLA Sky5 news copter
0-12-195 - taxi company in Malibu

Unknown # 2
4 - 471.2625
12 -
20 -
Noted TG:
0-04-134 - Northridge address
0-04-197 - "Comm 1"
0-04-115 - Van Nuys Tow
0-04-078 - Valley Tow

Unknown # 3
6 -
7 - 463.55
13 -
0-07-105 - Spanish taxi

Unknown # 4
8 -
12 - 472.450
13 -
20 -
0-12-041

Unknown # 5
4 -
14 - 472.0125 (careful there is a pretty strong user with PL 173.8 on here also)
18 -
0-14-013 - School buses - El Monte area
0-14-187

Unknown # 6
8 -
12 - 471.9625
16 - 472.3125 (This is also used on Nat. Sci Lukens repeater)
1-16-057
1-12-133 Riverside address heard

=


Any input would be appreciated.

 

[jazzbassNick]

My first foray into LTR, so I'm not sure what's helpful or not, but using LTR Analyzer on Unknown #4, I see LCN=2, I've seen the following IDs: 2-172, 2-50,2-51. Free values seem to be 1, 4, or 7.

Any direction for this total noob is 100% welcomed
I'm limited to RTL sticks, no real scanners.

 

[jazzbassNick]

Here's the stats from LTR Analyzer after running approx 20 hours:

  LCNs seen:   01 02 -- -- 05 06 07 -- -- 10 -- 12 13 14 -- 16 -- -- -- --
  Hit counts:      2                             1     1     1            

  Monitored:   -- -- -- -- 05 -- 07 -- -- -- -- -- -- 14 -- -- -- -- -- --

  Groups seen: 01-137 05-141 07-104 07-105 12-112 16-128

Not sure if that's helpful or not...

 

[LAflyer]

Thanks, pretty similar to what UniTrunker does by mapping LCN positions and showing noted talk groups.
Unfortunately not much help in ID'ing the actual missing frequencies for the LTR.

One of the issues I've run across over the years is many of the LTR companies have several dozen frequencies issued by the FCC to multiple sites, so it often requires one to monitor all of them to find the needle in the haystack. Add in the fact that RF rich environment like LA this means many frequencies have multiple users across the basin as well.

 

[jazzbassNick]

I'm wondering if this is it: ULS License - Industrial/Business Pool - Commercial, Conventional License - WNQR527 - JEFFRHON INC DBA SANDYS COMMUNCATIONS - Locations Summary

So how does one actually get to the stated goal? Monitor another suspected frequency and see if yields similar data?

All this is totally new to me, but very cool.

 

[LAflyer]

Yeah pretty much.

1) Find a licensed party for the confirmed frequency
2) Listen to other frequencies which they hold licenses for
3) Find LTR activity that matches LCN map order and matching talk groups.
4) One by one match the LCNs

 

[jazzbassNick]

Cool. I'll have to put this in a spreadsheet so I can see them all at once and start trying to narrow it down.

I'm thinking I should start with a physical location near me?

 

[1234567890]

I thought Lindsay learned his lesson with posting MRA's databus back in 2009?

MRA has more money than Lindsay. OP, you should probably search the FCC database for the frequencies you are looking for info on, and edit your post accordingly. MRA is quite litigious.

 

[LAflyer]

We have tons of non-MRA LTR listed in the Los Angeles Db. Thousands of users including bulk of Ambulance providers in the area utilize LTRs, so there continues to be good interest in monitoring these systems.

Additionally there is no confirmation that the potential noted LTRs frequencies belong to MRA as FCC database shows frequencies in most cases licensed to multitude of users across SoCal.

Lastly, there is nothing taboo talking about this subject.

 

[bcorbin]

We have tons of non-MRA LTR listed in the Los Angeles Db. Thousands of users including bulk of Ambulance providers in the area utilize LTRs, so there continues to be good interest in monitoring these systems.

Additionally there is no confirmation that the potential noted LTRs frequencies belong to MRA as FCC database shows frequencies in most cases licensed to multitude of users across SoCal.

Lastly, there is nothing taboo talking about this subject.

...and some of the digital systems... NXDN at 454, 471 and DMR up around 507, 508 - there's a whole bunch of stuff just waiting to catalogued, categorized and listed 8*)

I'm a scientist, not a lawyer, and really couldn't give a rat's patooty (I'm waiting to see THAT in a paper!) about the credibility of legal threats, etc etc... Data is data... the observation that 'data is consistent with an LTR system on xxx, yyy, zzz with the organizational structure 111-222 taxi, 222-333 security' is just that - an observation. Linking it to a particular provider might be problematic, if, for business reasons they don't want someone mining that data - but is it really necessary? A listing as 'unidentified provider' might be sufficient (the aggrieved party would have to out themselves).

 

[blantonl]

See the section related to MRA data removal here:

Restricted Info - The RadioReference Wiki

 

[LAflyer]

Thanks for the detective work. We've identified one new site so far.


Comm Enterprises - Hacienda Heights
01 - 507.750
05 - 508.1875
07 - 508.250
19 - 508.9625

So far 6 TG, all towing related.


New entry in Db has been made.

 

[jazzbassNick]

@LAFlyer - getting back to this hunt on Unknown #3
I've got SDRTrunk set up. It's great because it does LTR and it can monitor multiple freqs with a single dongle.

I set up a system for each callsign I found as potential solutions.
So far I've monitored 3 freqs simultaneously based on WPVX371 and 5 freqs simultaneously on WNQR527.
Just not sure what the next step is with all this data I've logged. I guess I'm hung up on

3) Find LTR activity that matches LCN map order and matching talk groups.
4) One by one match the LCNs

Both have activity - WNQR527 has much much more.

 

[LAflyer]

Do you have logs that show list of noted talkgroups for the frequencies you monitored?

By comparing the talkgroups, if the same ones shows on more than one frequency that helps likely confirm the frequency monitored is part of the same LTR system.

 

[jazzbassNick]

Got it - thank you.

I've got logs, just need to find the time to look at 'em

 

[LAflyer]

For reference we have a new listed LTR in the Db.

Air Communication Services Inc. (Mt. Lukens)

LCN 11 - 463.6
LCN 12 - 463.7
LCN 13 - 461.9

Most identified TGs users so far are dial-a-ride provider and Crown Disposal services.