The following information is from WWW.GROVE.NET :
     UNIDEN INTRODUCES REVOLUTIONARY TRUNK TRACKER SCANNERS
This is an ADVANCE POSTING of feature story appearing in the
March 1997 issue of Monitoring Times magazine.
This is an article we have been waiting to write for over a
decade. Ever since the early 1980s, when trunking radio systems were
first constructed, public safety monitoring has taken a down turn.
While trunking systems have generally been a boon to its users,
offering tremendous flexibility with limited spectrum, the news media,
off-duty police and fire officers, hobbyists, andothers were often
left out in the cold.
We won't bore you with a re-hash of how trunking works; suffice it to
say that trunked systems, generally comprised of anywhere from three to
29 frequencies and controlled by a singledata channel, can provide
communications for hundreds of groups of users, from the dog catcher to
the fire department arson squad. Conversations on trunked systems
often jump frequencies between replies. It becomes very difficult, if
not impossible, to follow a conversation, especially on busy urban
systems.
Years ago when many of us first began to scan, you knew that your
local police operated on 460.500 MHz, your local fire department on
154.445 MHz and your local highway department on 37.900 MHz. With
trunked systems, you can never tell on which frequency (again, among
a group of three to 29 frequencies) a particular agency will
communicate. Many people whomonitored as part of their work (the news
media), off-duty public safety officials, and casual scanner hobbyists,
gave up monitoring when their local departments went trunked: It
wasn't worth the effort. News reporting suffered, off-duty response of
emergency personnel may have suffered,and the hobby suffered, as did
the scanner industry.
Uniden has just changed all that. Their new TrunkTracker scanners,
which made their debut at the recent Consumer Electronics Show in Las
Vegas, will allow you to follow the communications of agencies which
operate Motorola analog trunked radio systems. Simply put,these radios
are a marvel. They work beautifully, they themselves are extremely
flexible, and,perhaps best of all, TrunkTrackers are a blast to use.
The first TrunkTracker to be released is the Bearcat 235XLT
handheld. This scanner uses the same tooling (case mold) as the
popular Bearcat 220s and 230s, with only one keypad change:the TRUNK
key. The 235 is a fully functional conventional scanner (some people
have mistakenly assumed the TrunkTracker will only work on trunking
systems). The 235 operates either in conventional or trunking mode,
though not both at one time. Also, while you are in the trunking mode,
only one trunked system--which can represent hundreds or thousands of
users--can be monitored at a time.
Channel capacity of the 235 has increased 50 percent to 300 channels,
as opposed to the 200 channels previously included in the 220s and
230s. Band coverage remains the same (standard scanner ranges,
including 800 MHz and VHF aircraft). In conventional search and scan
mode, the radio will operate as it always has.
There are a couple of minor changes. The TRUNK key replaced the WX
(weather) key. Now, to select weather search, which scans all NOAA
weather frequencies for an active channel in your area, the user hits
the SERVICE key. Weather is now part of Service Search, along
with Police, Air, Marine, Fire/Emergency. One handy little new feature
of Marine service search is that when an active channel is landed,
scanner display will flip-flop between the active frequency and the
marine channel number, e.g., "156.800" flashes alternately with "CH
16."
Check out the Uniden BC235XLT Specifications.
Now on to what you really want to read about: TrunkTracker operation
and features. You'll see as you read the report below that Uniden
worked hard to make TrunkTracker functions as intuitive and as
"scanner-like" as possible.
   Programming
To make TrunkTracker work, users first enter the frequencies of the
trunking system they wish to listen to (using the repeater output
frequencies), just as they would program a conventional scanner. Uniden
will be supplying a book of trunking systems and frequencies around
the nation,prepared by Rich Barnett, in the box with the scanner.
Police Call or one of the CD-ROMs on the market which contain the FCC
database are also good resources for this information.
Before you begin entering frequencies, though, you first must tell the
scanner that you are about to program a trunking bank. You do this by
pressing and holding the TRUNK key for 2 seconds. The radio emits a
double-beep tone and the bank icons begin to flash in the display.
The user then identifies which bank (1 through 10) he wishes to program
with a trunked system. Once the bank has been selected, the display
jumps to the first channel in the desired bank (channel 91 in bank
three, for instance). The TRUNK icon appears in the display as the
user programs the frequencies for the chosen system.
If a user enters a non-800 MHz trunked repeater output frequency, he
will receive an error message. The initial TrunkTracker models will not
track 900 MHz systems, although this featureis contemplated for future
versions. As of today, there are no known 900 MHz analog publicsafety
systems in the U.S.
   Search
Once the programming is done, the user will hit the SEARCH key and
you'll notice the scanner zip through those programmed frequencies as
it looks for the data channel which controls the system. The data
channel broadcasts a continuous stream of data and sounds like a
non-stop braaaaap. The data channel generally changes every 12 to 24
hours, but this has no effect on TrunkTracker operation.
Once the radio has acquired the data channel (it usually takes a
couple of seconds at most),the radio will begin to trunk. Instantly,
talk group ID's will begin to appear on the display, such as"512" or
"20448." Frequencies, now irrelevant, are nowhere to be seen. It's a
completely new paradigm for scanning, and it's enjoyable to use and
watch in action.
These group ID's represent a cluster of users. "512" might be Police
Patrol, East Side Operations, and may include 30 officers on foot and
in squad cars. "20448" might be the administrative group for the
Sanitation Department supervisors.
You won't know exactly who uses these IDs until you've either
monitored for awhile, or until talk group ID lists start showing up in
frequency books and on web sites. You'll easily nail down police, fire,
and emergency medical system (EMS) IDs in a matter of a few
minutes. Sometimes--for instance, on countywide trunked systems which
serve a number of city and townpublic safety agencies--it could take
an hour or so to figure out which ID matches up with which community.
ID cracking is half the fun of TrunkTracker! The important IDs are
easy: Figuring out the secondary channel ID for the town of Podunk
building inspectors ... that's the challenging part. Rest assured,
hobbyists will have a ball with it. There is a web site,
trunktracker.com, under development that may contain
system manufacturer information (Motorola, Ericsson/GE, Johnson, etc.)
frequency data and IDinformation. We also suspect that IDs may begin
showing up in frequency guides in the near future.
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