74 English
When you want to store a conventional system, all you need to know is
the frequencies they operate on. When you are scanning a conventional
system, the scanner stops very briefly on each channel to see if there is
activity. If there isn’t, the scanner quickly moves to the next channel. If
there is, then the scanner pauses on the transmission until it is over.
Simplex Operation
Simplex systems use a single frequency for both transmit and receive.
Most radios using this type of operation are limited to line-of-sight
operation. This type of radio is frequently used at construction job sites,
and with inexpensive consumer radios such as PMR radios. The range
is typically 1-8 miles, depending upon the terrain and many other factors.
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.
Understanding Banks
Channel Storage Banks
To make it easier to identify and select the channels you want to listen
to, the 500 channels are divided into10 channel storage banks
containing 50 channels each. You could use each channel storage bank
to group frequencies by department, location, area of interest, or any
other way you prefer. You can listen to any or all of the banks by using
the number keys to turn them on or off.
Service Search Banks
The scanner is preprogrammed with many of the frequencies allocated
to Emergency, Freenet, PMR, Marine, Aircraft, CB radio and HAM radio
services. There are 7 banks allocated for these searches that can be
