For some PL decoders, a weak noisy signal will trigger the PL detect and let
the signal through. On the other hand, if the co-channel signal happens to be
using the same PL tone, it will get through also. A good PL decoder like the
TS-64 will rarely false.
I have a repeater configured so that either a quiet (20 dB quieting on a SINAD
meter) or the correct PL tone will trigger the repeater. I tell users that if
they are having problems holding the repeater to use the PL tone to extend
their receive range.
The PL decoder in my Zetron 38As will detect the tone and key the repeater when
nothing but noise is heard on the output. I have to combine the PL with the
COS to get normal operation from this setup.
If you are using one of the older PL decoders such as one normally used in a
mobile radio, I would suggest changing to a better decoder, like the TS-64. It
will also encode and decode at the same time, saving having to install a
separate encoder in a repeater.
73 - Jim W5ZIT
--- On Tue, 11/18/08, ptt_pupil <[EMAIL PROTECTED]> wrote:
From: ptt_pupil <[EMAIL PROTECTED]>
Subject: [Repeater-Builder] 450-460mhz Repeater Co-Channel Interference
To: Repeater-Builder@yahoogroups.com
Date: Tuesday, November 18, 2008, 12:30 PM
Can anyone tell me if there are ANY fixes for co-channel
interference?
What is the use of a PL tone if it isn't able to block out the co-
channel users? Is it because the co-channel user is transmitting with
more power and is able to break the PL tone? What are the expectations
of a PL tone? When does it work and when does it not work? Are there
other devices that can help all? Thanks in advance!
,_._,___
