Terms and Definitions
Frequency
Radio signals are sent as waves through the
air. These waves move up and down. A
frequency is the number of times in a certain
time period, usually a second, that these
waves move all the way up and all the way
down and back to all the way up. For example:
123.44 kHz means that the waves are moving
all the way up and all the way down and back
all the way up again 123,440 times each
second.
Mobile Extender
When highway patrol officers step away from
their cars, signals from the patrol car are sent
to their portable radios via a mobile extender.
The mobile extender is a transmitter/receiver
that receives the signal from the station and
transmits it to the portable radio on a different,
but lower, frequency.
Scanning
Scanning is the process by which your
scanning radio looks for “activity” in the
channels it is programmed to look at. The
scanner checks each frequency for the
presence of a signal, and when it finds a
frequency with a signal, for example someone
talking on it, it stops, allowing you to listen to
the signal. The BCT-10’s Highway Patrol Alert
System also looks for activity on mobile
extender frequencies. When the BCT-10
detects the presence of a signal on one of
these frequencies, it will trigger an audio and
visual alarm.
Introduction
2
