19
Understanding Scanning
cycle resumes until the scanner receives another trans-
mission.
What is Searching?
The BC246T can search each of its 21 bands and up to
10 bands together to find active frequencies. This is
different from scanning because you are searching for
frequencies that have not been programmed into the
scanner. When you select frequency bands to search, the
scanner searches for any active frequency within the
lower and upper limits you specify. When the scanner
finds an active frequency, it stops on that frequency as
long as the transmission lasts. If you think the frequency
is interesting, you can program it into the scanner’s
memory. If not, you can continue to search.
What is CTCSS/DCS?
Your scanner can monitor systems using a Continuous
Tone Coded Squelch System (CTCSS) and Digital Coded
Squelch (DCS) system, which allow squelch to open only
when the tone you have programmed with a specific
frequency is received along with a transmission.
CTCSS and DCS are subaudible tone signaling systems
sometimes referred to as PL or DPL (Motorola’s trade
-
marked terms for Private Line and Digital Private Line
respectively). CTCSS and DCS are used only for FM
signals and are usually associated with both amateur and
commercial two-way frequencies. These systems make
use of a special subaudible tone that accompanies a
transmitted signal.
CTCSS and DCS are used for many purposes. In many
cases, CTCSS and DCS are used to restrict access to a
commercial repeater, so that only those units, which
transmit the correct tone along with their signal can “talk”
to the repeater.
CTCSS and DCS are also used in areas that receive
interference where there are several stations with output
frequencies close to each other. When this occurs, you
might hear multiple communications on the same