Lisha,

If you want to tap into local police and fire bands, you'll need to get
a radio scanner which supports trunking. The easy way to get started
is to run down to Radio Shack and buy one -- they range between $80 and
$250 for handheld and base units.

There are a few things you should know first, however. There are
typically several police frequencies allocated for each district. You
should start by trying to find these out. Radio Shack sells a guide
which covers tri-state areas and is an excellent source. There are also
some good database references on the internet. Anyway, once you find
out these frequencies, you'll want to make sure you get a scanner which
can listen in on these.

Usually around the 866 MHz range or 155 MHz range, most scanners will
pick these up. You'll be able to tune in the scanners for a specific
channel. However, most scanners are not usually used in this fashion
(listening to only one frequency at a time). This is okay for listening
to one-way weather advisories and such. However, most of the time you
will scan through many frequencies and listen in on active ones. When
it becomes inactive (conversation silence), you can stay put or keep
scanning. However, you should know most most public organizations will
not simply broadcast a single conversation back and forth on a single
frequency; instead they use a different scheme.

With about a dozen frequencies allocated to them, a police station will
often implement what's called trunking. Special units are placed in the
trunks of police cars so that when an officer wants to make a call, the
unit finds an open frequency in the set and broadcasts on this. In the
transmission it also includes a special group ID code which uniquely
identifies the broadcast group. The problem with only using one
frequency is if many cops are sharing the same single frequency, it's
quite common to have to wait in order to broadcast. With trunking, they
can seamlessly broadcast without worry and without waiting for the line
to clear.

Therefore, to a person listening on one frequency, they will only hear
sporadic conversations. This is because it's possible for a
"conversation" to initiate on Freq A, be replied to on Freq B, be sent
the third time on Freq C, et cetera.

To tune in to a single conversation, it's important to get a trunking
compatible scanner. When you program in a group of frequencies for a
fire or police department into a trunking set, you can scan through the
whole set. This will allow you to listen to all the conversations on
this trunking set. When you find a particular conversation you want to
hone in on, you can HOLD DOWN a trunking button (at least that's how
you do it on the Radio Shack Dual Trunking model) and it will detect
the group ID being used and subsequently filter all conversations down
to only this group ID. Then you'll be able to hear a cop radio to
dispatch and vice versa, following an entire conversation thread end to
end.

One more thing, for trunking to work, each trunking set needs a
dedicated control frequency to send control messages. You can find out
which is the control by listening to the loud modem-like noises or
reference a comprehensive guide.

Also, there are two main types of trunking protocols, Motorola and
EDACS, as far as I know. Make sure your unit can support what your
local area uses. Happy scanning!

- D

Indexing topics: Want to access police or fire frequencies with a
scanner? How does police scanning work? What is trunking and how does
it work? How do I get started with scanning?



Lisha wrote:
This might sound like a stupid question but I never understood what trucking
actually mean???

Lisha
"Celt Chic" wrote in message
...
Hi everyone,

I'm sure everyone is going to sigh in boredom when they hear this
question, but I just bought a Pro-95 Scanner and I'm completely lost
to the whole trunking thing. I've read the manual three times, I've
checked out trunking web sites, and even read a site that pretty much
rewrote the manual. None of these help. I think my brain is in a
stage of rot. Can someone start me off from the beginning, say, by
teaching me how to program a basic Mot II trunking system in my
scanner? What all do I need to do? Please give it to me step by
step, and maybe then I can advance on to Edacs, and then possibly to
Mot I where it also requires fleet maps. They need a trunking book
for dummies because I really have no clue and would appreciate the
most basic help I can get.

For example, here is a set of frequencies that is published on the
trunkedradio.net for Radioland in Floyds Knobs, IN. What would I do
with it starting from the beginning?

System Name: Radioland 900Mhz (Indiana)
Location: Floyds Knobs, IN
County: Floyd
System Type: Motorola Type II Smartzone
Last Updated: 03-16-02 17:01
Hits: 14

System Frequencies
Site Description Freqs
001 Site-1 936.6875 936.7125 936.7250 936.7375 936.7500 937.6375
937.6500 937.6625 937.6750 937.6875

Thanks so much! Once I get the hang of this I know I could do
everything else on my own!

Another question, do all of the trunked systems have to start on
channel 00 in the banks, or can I have multiple trunked systems in
the banks? I believe I can only have motorla in one band and edacs
in another, but can I have multiple systems in each bank? For
instance, since edacs must be in order, can I have 12 frequencies of
edacs starting from channel 400 going to channel 411, and then have
another edacs system starting from channel 412 to channel 430?

Muchas gracias!

--
~~~~~~~Surfing Radio Frequency Waves~~~~~~~
Celt Chic - WA9012SWL
email me at (but first remove nospam)
In the process of moving my web page from http://www.ius.edu/sdean to
http://home.att.net/~monster-masher/
Web page last updated March 20, 2003.