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<font face="Helvetica, Arial, sans-serif">Bob,<br>
<br>
Thanks for the education. For a short time, back about 1978 to
1981, I converted a Motoroal base station into the first 147.61
repeater for Vail, CO. I seem to recall that PL was just beginning
to be used by some PDs in Denver but none of the ones in my area
of the Western Slope. From 1981 until recently, I've been away
from ham radio and not following current developments and the
evolution of practices.<br>
<br>
So, some more questions. Use of CTCSS or DCS is a "local option"
and the decision to use it on a repeater's retransmission is a
separate local decision. Using the same PL tone (or DCS code) on
the repeater's input and output has evolved into a "usual and
customary practice" and is not a requirement. Further, it is used
in an attempt to restrict a repeater to only retransmitting
signals that are really intended for it and its users. Adding that
tone or code to the repeater's output merely adds value for the
user since spurious signals on the repeaters output freq are
"hidden".<br>
<br>
Further, many of the UHF/VHF ham radio manufacturers have built
the usual and customary practices re: CTCSS tone/DCS code use into
their radios to simplify circuit design and complexity. The
consequence is that it reinforces the usual and customary
practices. An unintended consequence is that users assume that the
usual and customary is an absolute, immutable rule. It alsomakes
life substantially more difficult for the admin/operator who needs
to use different CTSS tones or DCS codes on a repeater's input and
output frequencies. I know of a system (Colorado Connection) where
there are a few VHF-VHF links in a larger system. <br>
<br>
Have I captured the gist of the matter, Bob?<br>
<br>
Again, thanks for the explanation. After I sort out a few more
"things" I'm going to become more active around here and try to
meet some of the folks who maintain local repeaters. As an aside,
one thing that puzzle2 s me is the general lack of traffic that I
hear. One of those "things" is building or buying better antennas
for my QTH (covenant-restricted subdivison) and my van.<br>
<br>
73 de KK4DBR, Ron<br>
<small><small>EL98fk Windermere, Orange Cty, Florida<br>
living in the massive shadow of a wee rodent</small></small><br>
<br>
<br>
<br>
On 8/9/2011 11:19 AM, Robert Terzi wrote:</font>
<blockquote cite="mid:4E415018.206@r-t.org" type="cite">
<pre wrap="">On 8/9/2011 9:45 AM, Dan Smith wrote:
</pre>
<blockquote type="cite">
<pre wrap="">On 8/9/2011 12:49 AM, Ron McKenzie wrote:
</pre>
<blockquote type="cite">
<pre wrap="">[...]
Some questions to help increase my knowledge of current practices:
[...]
2. Is a repeater operator precluded from selecting different CTSS or
DTCCS codes for Rx and Tx?
</pre>
</blockquote>
<pre wrap="">
Yes, at the moment.
</pre>
</blockquote>
<pre wrap="">
Err, perhaps repeater operator is a bit ambiguous here?
The repeater owner/administrator, who configures the repeater can
can set up a repeater with different tone or digital squelcn
settings for transmit / receive. The occurrences of this are
pretty rare, and a number of popular radios do not support the
setting of different squelch encoding / decoding on the same
memory channel. However, I've seen a couple of popular linked
repeater systems in the NYC area move to this configuration
to avoid interference.
Also, I'm going to take the risk of being a bit pedantic here
since I've seen a lot of misunderstanding on different mailing lists.
CTCSS, Aka Tone Squelch, or PL (Private Line) is a method for
including an analog tone in a transmitted signal in order to
allow the receiver to operated in a mode where it will only
open the squelch if the tone is present. This prevents noise or
even other undesired signals from being heard.
DCS, Digital Coded Squelch, uses a digital code embedded in
the transmitted signal that provides for more possible squelch
codes and greater reduction in an unwanted signal opening the
receiver's squelch.
The typical repeater setup (especially in the US) is that the
repeater's receiver has a tone squelch setup to prevent the repeater
from keying up on unwanted noise or signals. This means that in order
to use the repeater, your radio must *encode* the squelch tone in your
transmission.
The repeater when retransmitting a signal may encode a squelch
tone or digital code. This is a feature for the convenience of
the people who listen to repeater to provided added protection
against hearing unwanted noise or signals. None of the receive
squelch settings on your end are required to use the repeater
and if set incorrectly can prevent you from hearing the repeater.
Given that it is often best to make sure you've got the settings
for the repeater working correctly before you enable any receive
squelch settings for that memory. If you don't live in a noisy
area you could skip that step entirely.
About half of the repeaters that I've come across do transmit
tone squelch which makes monitoring and scanning that much
more pleasant. I've only come across three repeaters in my area
so far that use DCS.
The most of the non-typical setups I've seen are from linked
repeater systems in areas that are densely packed with radios.
Hope This Helps,
--Rob
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</pre>
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