On Wed, 21 Jul 2004 11:57:30 GMT, "DougSlug"
wrote:

Good explanation...I'll just add that some scanners do offer a CTCSS feature
so that you only hear the transmissions of interest, but most do not.
Certainly you do not NEED a CTCSS-equipped scanner to monitor transmissions
using CTCSS tones.

It can, however, be helpful to have at times.

Where I live, I'm halfway between two localities whose police
departments use the same frequency but different CTCSS tones. They are
in neighboring counties and don't interfere with one another's
operations, but inasmuch as I am on the border between the two
counties, I can hear both dispatchers.

Trobule is, I'm really only interested in monitoring one of the two,
because as a ham involved in ARES/RACES, I'm listening to the one in
my county of residence.

Since I have a CTCSS-enabled scanner (PRO-2045 with the optional CTCSS
board installed), I only have to listen to the one I want to hear, and
my scanner isn't stopping on the transmissions from the other
department in the neighboring county.

It's also very helpful on the low VHF band where tropo ducting brings
in low-band fire comms from clear across the state at night. Great if
I want to DX the low VHF band, I can just turn CTCSS off, but if I
want to take a nap and only have the scanner wake me up if there's a
fire here in town, I can set CTCSS on and the scanner will only go off
if the local fire companies become active on the air.

In summary, CTCSS is certainly not required to hear anything, but it
can sure come in handy to have this feature on your scanner.

Finally, I note that the original poster's address included a ham
callsign, so I will note that most VHF/UHF repeaters nowadays are
using CTCSS on the input side at the very least, whether they
retransmit the tone or not, and so amateur radio gear for the 2m and
440 bands pretty much must be equipped with CTCSS encode at least,
unless you want to be limited to using the rig only on simplex.

CTCSS is also often referred to as PL (for Private Line, Motorola's
trademark for its implementation of CTCSS on its commercial
transcievers), and also as CG (for Channel Guard, which is General
Electric's name for the same technology).

Hope this helps!

John D. Kasupski, Tonawanda, NY, USA
Amateur Radio (KC2HMZ), HF/VHF/UHF Monitoring (KNY2VS)
Member ARATS, ARRL, WUN