TrunkTracking Tips and answers to Frequency Asked Questions (FAQS)

by Ben Saladino, KC5IRJ 12/20/2003
Check out the new Radio Manager 2002 for Windows! (TrunkTracking Control Software)

Return to Scanning the Dallas/Fort Worth Area


What is TrunkTracking or a TrunkTracker?

A TrunkTracker is a Uniden scanner that is capable of tracking analog trunked two-way radio systems used by police, fire, EMS, public works, and business users to name just a few. For an explanation of trunking, pleaseclick here.

Where do I get one and how much does it costs?

I paid $300 from Grove Enterprises when they first came out. You can now get them cheaper, but I would not hesitate to pay $300 or more again, because this is THE SCANNER to have! You should probably watch some of the scanning news groups or mailing lists to get a better idea of going rates and availability.

Will a TrunkTracker follow digital modulation trunked systems?

Yes, starting with the Uniden BC250D and BC895D and Radio Shack Pro-96 scanners, Digital has come to Scanners! The latest out as of 12/20/2003 are the Uniden BC296 and BC796 scanners. All of these scanner can receive APCO 25 protocol. However there are some limitations on them.

Do I need one?

If you want to monitor Motorola, EDACS, or LTR trunked radio systems, YES! Although you can scan the same trunked systems with a conventional scanner, a TrunkTracker really makes scanning trunked systems enjoyable. The larger the number of users on a trunked system, the more you need a TrunkTracker. With a TrunkTracker you will be able to monitor a channel or "talkgroup" without having to continue to hit the scan button like you would have to do with a conventional scanner, AND you can lockout data channels and public works channels that would otherwise be a real pain.

Who makes TrunkTracing Scanngers?

Uniden and RadioShack.

Do you need to know all of the frequencies of the trunked system you want to monitor?

Yes, in most cases. Even though the frequencies may be part of the data stream that the TrunkTracker monitors it is still necessary to program in all of the frequencies used by the trunked system. The newer generations have "Control Channel" only modes where you only need to know the control channel frequencies (usually 4).

Does a TrunkTracker work like a conventional scanner?

Yes. You can either scan conventionally or TrunkTrack.

Can you scan conventionally and TrunkTrack at the same time?

On some of the later models, yes.

Can you TrunkTrack more than one trunked system at a time?

On many of the later models, yes.

How do you scan a trunked system with a TrunkTracker?

These are the very simplified general steps to scanning a trunked system with the TrunkTracker.

Program the frequencies used by the trunked system using the Trunk Programming mode. If you do not include all of the frequencies for the system, you will probably miss some transmissions. The frequencies can be found in Police Call frequency lists available from your local Radio Shack, FCC records available on CD-ROM from several vendors, and places like this.

Determine the proper Fleet Maps for the trunked system. Newer trunked systems are more than likely Type II systems, but there are still Type I systems in use and some systems that combine the two. See the TrunkTracker Operating Guide for further explanation. For trunked systems that are all or part Type I systems, determining the proper fleet map can be complicated, but it's well worth the trouble, and fleet map settings are already starting to show up on the web at places like this.

Search for and learn the channel or talk group ids of the trunked system. I enjoy this part of the scanning hobby more than anything else. It's simply cataloging ids by matching them up to their users, much like searching with a conventional scanner. If you don't like that part, then be patient and wait for the information to make it's way on to the Internet and into printed publications.

Program the Scan Lists with the talk group ids that you want to scan. This is very similar to scanning with a conventional scanner, but instead of frequencies in memory you'll be seeing talk group ids.


What is a Fleet Map?

Simplified, a Fleet Map is used by the trunked radio system to determine the number and lay out of channels and users on the system.

What is a Block?

The TrunkTracker and radios in trunked systems use blocks (of data) for storing information, the Fleet Map. There are 8 blocks number 0, 1, 2, 3, 4, 5, 6, and 7. Each block can be either Type I or Type II. Each block is 8 kilobytes or 8192 bytes.

What is Type I and Type II again?
When a radio in a trunked system is keyed it not only carries the voice or data of its user, it also sends an id and other information. Type I blocks get more information from the radio than Type II blocks. A Type II radio's extra information is stored in the trunked system controller computer and is matched up with the radio's id.

It sounds really complicated, is it worth the trouble?


How do you determine if you are listening to a Type I or Type II block?

If the talk group id is an odd number, you are probably listening to a Type I block.

If the talk group id fluctuates while you are listening to what you know is the same talk group, you 're probably hearing a Type I block.

If it seems like your are missing parts of conversations, the you are probably hearing a Type I block.

If lots of talk groups are separated by 32, then you are probably listening to a Type II block. If two talk groups seem to be consecutive, and the difference between them is 32, then you are probably listening to a Type II block. For example, you know BPatrol 1 is 432 and BPatrol 2 is 464, then it's more than likely a Type II block. That's where good old listening to the scanner comes in handy. If you hear officers refer to the channel as BPatrol 1 and BPatrol 2, then it makes it that much easier to identify talk groups. If you've been scanning conventionally, it's the same technique you've probably used to determine what frequencies are called what.

I know it's a Type II system I'm monitoring, but I see some odd number talk group ids. What gives?

There are certain situations when a Type II talk group will not be an even number. For instance, I've noticed that some fire station alert tones are often on odd number talk group ids. Also I heard a police chase where the normal talk group id was change by three. For example, 2704 becomes 2707. It was probably due do the talk group being patched to another.

Here's some more information on that topic. Thanks to a regular Scanning the Dallas/Fort Worth visitor

Added 1 (16 becomes 17) = ATG (All Talk Group, sort of a fleetwide thing)

Added 2 (16 becomes 18) = Emergency Talk Group

Added 3 (16 becomes 19) = Crosspatch (bidirectional)

Added 7 (16 becomes 23) = Multi-select (simulcast by dispatcher)

Added 8 (16 becomes 24) = DES (digital encryption) in use


When TrunkTracking, think of talk group ids as frequencies. You have to figure them out just like you had to figure out what frequencies to listen to. You can search for them, you can scan them, you can manually tune them. There can be hundreds of them on a trunked system.

The same talk group id can be used in separate trunked systems and may have absolutely no connection between the two.

If you hear users talking about going to another channel and you don't know what that channel is, hit SEARCH! For example, you are monitoring talk group id 2160 and you hear one officer transmit to another "321 to 329, go to talk one". Hit the search key and listen for the same voices or a response like "329 to 321, on talk one". Log that talk group id with the note Talk 1.

In a Type I block, primary users' primary channels are likely to be on ###-1 For example, you are more likely to see Police on 700-1 and Animal Control on 700-15, than Animal Control on 700-1 and Police on 700-15. However, this is only a rule of thumb, and there's reason it couldn't be the second way.

Use a spreadsheet or other program to help sort out and organize the talkgroup and fleet information you find.

Additional Resources

TrunkTracker Website at There's information there on the TrunkCom mailing list.

Some help from the developer of the TrunkTracker scanner.

My initial Review of the BC-235XLT TrunkTracker.

Return to Scanning the Dallas/Fort Worth Area