LTR Mapping with Uniden Bank Scanners

From The RadioReference Wiki

The following is a method for Mapping an LTR System for Uniden Bank scanners.

Method #1
Identify most of the Active HH's first, and then use method #2 for the rest. This method is faster and produces more interesting information right away.

  • Evaluate all of the frequencies under the same call sign, or even different call signs for the same Licensee, or FRN, in the same general location.
  • Assign the bank trunking system as LTR.
  • Enter each frequency twice as in the following example. At this point, they do not have to be in positions 1-20. The example will have them starting in 21.
   Pos  Frequency  Trunk Setting
   21   462.5000    off (conventional)
   22   462.5000    on
   23   463.2500    off (conventional)
   24   463.2500    on
   etc, etc

Note: if your scanner does not allow conventional and trunking in the same bank, then just program all the frequencies once as conventional, and note the active ones. Skip directly to Method 2 and enter these active frequencies first.

  • Start monitoring. Take note of which channels are active. As you hear traffic on any of the conventional frequencies, quickly go to manual, and switch to the next position. I.E., if transmission is heard on 23, quickly switch to 24. If that frequency is trunked, you will see the TGID displayed. Most systems have one or more frequencies assigned as conventional, so don't be surprised if there is NO TGID displayed. If you find conventional frequencies, you can eliminate them from further investigation.
  • In a few days, you will often have located most of the active HH's, and you can put these in their correct positions (1-20) to start getting a feel for the system. You can also start making a list of TGID's. Your scanner may allow you to add them as received. For example, the BC796D does this with the transfer key.
  • If there is no traffic on one or more of the active frequencies loaded in their "correct" positions, go to method #2 and program all 20 positions with the each of these questionable frequencies to verify their correct position. This is also a good method to double check each frequency as you identify it.
  • Take note of the HH's display on each frequency. The active ones probably have users assigned, and the most frequently displayed HH will be the actual HH.

Method #2

The second is more scientific, but may take a little longer.

  • Try to find any conventional frequencies 1st so you can eliminate them in this method. Just "Sit" on each one to see if any TGID's are found. You can also program them as conventional and search for any PL/DPL'.
  • Since there can be up to 20 channels in an LTR system, program the lowest frequency into ALL 20 channels for that system in the 1st 20 positions in the selected bank. When a transmission is heard, hit the "hold" button and observe the TGID. On the BC796D, hit the Trunk Button, and it will tell you which of the 20 positions received the transmission.
  • This becomes more important as you try to find the GOTO frequencies. Repeat this several times to confirm audio is being received on this frequency for several different TGID's. If the audio is on talk groups A-05-GGG then that frequency is likely to be channel 05. Then repeat the process for the next highest frequency for all 20 channels.

Software Use

Often, systems are designed to use only the ODD channel numbers, and are assigned from lowest to highest frequency in the system. If you use software with logging, you can easily log these TGID and their associated frequencies. Since most LTR systems are active during the week, logging software is a big help. If not, then use the hold button during active searching as above. The problem with logging is that you can get false TGID's, or ones from other systems that will easily fool you into thinking you have LCN's for the GOTO.

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