Uniden BC246T User Manual

22

• The frequencies for many of the 800 MHz public 

safety systems are listed in the National Public Safety 
Trunked System Frequency Guide included with your 
BC246T scanner.

Conventional scanning is a simple concept. You enter a 
frequency used by someone you want to monitor into 
your scanner’s memory. For example, the police in your 
area might transmit on 460.500 MHz, the fire department 
on 154.445 MHz, the highway department on 37.900 
MHz, etc. So when your scanner stops on a frequency, 
you usually know who it is, and more importantly, you can 
stop on a channel and listen to an entire conversation. 
This type of scanning is easy and fun. 

However, as the demand for public communications has 
increased, many public radio users do not have enough 
frequencies to meet their needs, creating a serious 
problem. Trunking radio systems help solve this problem. 

While conventional scanning worked great while there 
were only a few groups wanting to use the frequencies, 
with the advent of smaller, lower-cost radios more and 
more agencies and businesses wanted to take advantage 
of the utility of 2-way radio. As a result, the bands that 
were used most became full, so new users were not able 
to take advantage of the technology as quickly as they 
wanted. 

Trunking solved this frequency shortage by allowing 
multiple groups to use the same set of frequencies in a 
very efficient way. While each type of trunking system 
operates a little differently (see the next few sections), 
they all work on the same basic premise: even in a 
system with a lot of users, only a few users are ever 
transmitting at any one time. 

Instead of being assigned a frequency, as with 
conventional systems, each group is assigned a talk 
group ID. A central computer controls the frequency each 
group operates on...and this frequency selection is made