Locating additional LTR frequencies
From The RadioReference Wiki
If you have exhausted the search for LTR frequencies from a system or systems in a 2-5 mile radius, depending on terrain, then you need to widen the search. There are many ways to approach this, and none are particularly quick or easy. The following explanation is for LTR Standard systems, although some of it will apply to other trunking systems.
Finding those “Rogue” frequencies
Different Call Signs from same Licensee
If there are more locations for the same licensee or FRN, within 10-35 miles (rough guide only), then program all of these frequencies as described for your scanner type in Mapping an LTR System. It is not uncommon for a licensee to use a remote frequency at a different site, without registering this with the FCC.
Other LTR systems within 2-5 miles
Look for other LTR systems from Different Licensees. Also look for conventional systems with 3 or more repeater frequencies from Private Carriers offering radio service. Then program all of these frequencies as described for your scanner type in Mapping an LTR System.
Searching for Other LTR frequencies
As a last resort, try searching in the 451-465 range. If the signals are fairly strong, you could use another scanner with an indoor antenna to help filter out all those other frequencies.
Tips and Techniques
- If you have a signal strength meter, look for signals of the same approximate strength as others on the system being mapped.
- Listen to the users on the system you have already mapped for distinctive dispatcher voice/sound, or type of conversations. This will help you spot those unique users on one of these “rogue” frequencies.