Finding LCNs on LTR system

[wk5h]

I can search for LCNs on my 436hp, but, I'm not getting but 2/5... I'm thinking I have the correct frequencies, but, I'm pretty fresh on LTR systems. So, let me pose this question for you guys who have a better understanding of them...

There is a communications company that has 3 licenses in the 450-460mHz range here. Each license has 5 "base" frequencies.

I have a Favorites group created for the name of the company (i.e. Joe Communication)
I have 3 system names, in respect to the license name (i.e. License 1, License 2, License 3)
Under each system, I have a department name called "Business" and a site named "LCN" with the base frequencies entered.

Joe Communication
--License 1
----Business
----LCN
-------451.30000
-------452.30000
-------461.07500
-------462.10000
-------463.37500

--License 2
----Business
----LCN
-------451.35000
-------452.35000
-------461.10000
-------462.20000
-------463.50000

--License 3
----Business
----LCN
-------451.90000
-------461.72500
-------462.05000
-------463.95000
-------464.77500


When I go to Menu, Analyze, EDACS/LTR/DMR LCN Finder, and select any of the 3 licenses, all it will ever find is 2/5 LCN numbers, even if I leave the scanner on searching overnight.

I know my ignorance of scanning LTR systems plays into this, but, would the fact that there's not just a whole lot of traffic on these systems be the reason I'm not getting the LCN numbers found and put in correct order?
Would it also be possible they have combined some of the licenses into one "system", and I should be combining 2 of them? 2 of the licenses according to the FCC are in the same location, and I would assume on the same tower, but, the 3rd license is about 20 miles away on a different tower.

Hope I didn't confuse anyone too bad on this...

 

[natedawg1604]

I can search for LCNs on my 436hp, but, I'm not getting but 2/5... I'm thinking I have the correct frequencies, but, I'm pretty fresh on LTR systems. So, let me pose this question for you guys who have a better understanding of them...

There is a communications company that has 3 licenses in the 450-460mHz range here. Each license has 5 "base" frequencies....

Sadly this is pretty typical of ULS data (especially with private systems), often you don't get 100 percent of the system frequencies from ULS entries. So, you may NOT have all the frequencies! At this juncture, you should forget about ULS data and instead conduct analog band searches for new LTR frequencies over the entire UHF band. In my experience Standard LTR frequencies emit a 5 or 10 second burst while the frequency is active, so that's a dead giveaway when running a band search. When a LTR system is not in use, you may find that a few frequencies continue broadcasting the burst while other frequencies go silent.

Also, LTR frequencies won't contain CTCSS or DCS tones. So if you find an analog frequency broadcasting voice traffic with no accompanying tones, it may be LTR. Finally, if you get a $20 RTL SDR dongle, you can use SDR programs such as LTRLogger to further analyze LTR frequencies and determine which LCN's are active on the system.

 

[wk5h]

Advice much appreciated - I do have a Nooelec Mini2 that I'll throw on a machine tomorrow and see if I can't sniff more frequencies out. It's a box I can set and forget for several days if I have to.

 

[nd5y]

Some LTR systems have "overflow" channels that are not used unless all the home channels are busy.
That could be the reason or it could be that the channels you aren't getting traffic on are not part of the system or are not use at all.
Some of the LTR systems in my area have more frequencies licensed than I have seen actually used.

 

[ecps92]

Also.. in my experience, in addition to "overflow" some channels were implemented in conventional mode for "Off LTR Talk"...

Some LTR systems have "overflow" channels that are not used unless all the home channels are busy.
That could be the reason or it could be that the channels you aren't getting traffic on are not part of the system or are not use at all.
Some of the LTR systems in my area have more frequencies licensed than I have seen actually used.

 

[INDY72]

All the above is true on business/SMR LTR TRS. Many sites liced but the freqs at one site are used at another, some freqs are overflow, some are conventional, some idle. Smaller systems are not too hard to decipher, but very large LTR systems can be challenging. There are many threads discussing how to determine LCNs... The 20 method, Eric Cottrells LTRlogger, the PRO-97, BCDX36HPs..... Have patience, and best of luck to you!

***Same is also very true on many business/SMR DMR and NXDN/iDAS systems, and a few Public Safety LTR/DMR/NXDN.***

 

[natedawg1604]

Also.. in my experience, in addition to "overflow" some channels were implemented in conventional mode for "Off LTR Talk"...

Wow, I've never encountered that before. Would the conventional mode typically be simplex or repeated?

 

[INDY72]

Both repeatered and mobiles only

Sent from my LG-K330 using Tapatalk

 

[ecps92]

either or, could be both

Wow, I've never encountered that before. Would the conventional mode typically be simplex or repeated?

 

[IAmSixNine]

Typically on an LTR system you will have a home channel. This is the primary channel the device uses when it is keyed up, It sends a request to the system, if the channel is free you talk. If its not the controller sends you to the next channel in line. This is all pre-determined during the system set up.
So for a small system its possible it wont get past 2/5 due to the primary channel and second channel not having much traffic.
Its also possible for a busier system to have a larger user on home channel 1 and other smaller users on say home channel 2. This will allow more efficient trunking of the 1 larger user and of the smaller additional users.

If its a slow system you may see a couple of channels almost never get used.

 

[INDY72]

Also be aware that a few LTR systems also do mixes of flavors, especially *standard* and PassPORT. Also, many SMR LTR systems are now setting up digital (DMR or NXDN) systems to replace the old LTR, and usually stand up the digital system alongside the LTR during transition using the same frequencies. This can make mapping a little more challenging. Eventually they hope to migrate all users over to the digital systems then will offline the LTR. And then the biggest SMRs will have both an digital option, analog LTR option, and conventional repeaters, both analog, and digital as options for customers depending on the needs.