22
Understanding Scanning
Repeater Operation
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
25-mile radius from the repeater location.
What is Trunk Tracking?
Your BC246T is designed to track the following types of
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 these important points:
• 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,
