Uniden UBCD996T - Manual (Page 24)

Repeater Operation
What is Trunk Tracking?
Repeater systems use two frequencies: one transmits from the radio to a central
repeater; the other transmits from the repeater to other radios in the system. With a
repeater-based system, the repeater is located on top of a tall building or on a radio
tower that provides great visibility to the area of operation. When a user transmits
(on an input frequency), the signal is picked up by the repeater and retransmitted
(on an output frequency). The user’s radios always listen for activity on the output
frequency and transmit on the input frequency. Since the repeater is located very
high, there is a very large line of sight.
Typical repeater systems provide coverage out to about a 40kms radius from the
repeater location.
Your UBCD996T is designed to track the following types of trunking systems.
Motorola Astro 25 (APCO 25) trunking systems.
Motorola Type I, Type II, Type IIi hybrid, SMARTNET, and PRIVACYPLUS analog
trunking systems, which are extensively used in 800 MHz communication
systems.
LTR trunking systems
EDACS SCAT trunking systems
EDACS trunking systems
When tracking these types of systems, you might want to remember that your
scanner can track more than one trunking system at a time and scan conventional
and trunked systems at the same time.
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.
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