[KYHAM] KEN Training for April 21: Considerations for Amateur Repeater Operations

[Ron Dodson]

Continued from last week. 
Thanks to Tony Whobrey, KY4SP for the following article on
repeaters. Part two of a two part series.
-------------------------------------

The use of sub-audible tone squelch <a.k.a. PL or Channel
Guard> can make your repeater far more pleasant to use, by
limiting the receiver's response to only those signals that
are actually intended for the system. A repeater that
frequently keys up
unnecessarily due to distant co-channel users or
interference from other nearby transmitters is an annoyance
to those who use
it, tone squelch greatly reduces such difficulties. This is
the principal reason why commercial and public safety
repeaters almost
universally use tone squelch, since the small expense
involved is more than offset by the benefits of reduced
operator fatigue.
The use of tone squelch in amateur service doesn�t mean you
have a closed repeater, as many people believe; a repeater
is
closed only if its owner says so. If your repeater has voice
ID capability, the tone frequency may be incorporated into
the ID,
to facilitate access by itinerant stations. Another subtle
contributor to operator fatigue is the �courtesy tone�
employed at the
end of each user�s transmission, as a reminder to listen for
others who may wish to contribute to a conversation in
progress.
Elaborate tones sound impressive at first, but can quickly
become bothersome, particularly when several repeaters are
linked
together. 

If this is your first project, don�t overlook the fact that
putting up a repeater is a small job compared to the
seemingly
never-ending task of keeping it working and available for
service. Have an adequate stock of spare parts available,
particularly
if your repeater is constructed from former commercial
equipment. Many of the units that are now becoming available
as
surplus are no longer fully supported by their
manufacturers; this is often the reasoning behind the
replacement of otherwise
flawless equipment. A complete spare repeater is worth
consideration, perhaps more so for those who must rely on
others for
technical help or equipment. A lower powered, less elaborate
(and accordingly less expensive) unit could provide
substantially
the same coverage while repairs are made to the primary
repeater. Before seriously considering a repeater project,
be sure that
you have access to adequate service and test equipment. You
don�t have to use a brand-new state of the art service
monitor,
but you should be able to measure forward and reflected
power, deviation and frequency. It is not possible to
properly align a
repeater �by ear�, and even a factory new station should be
checked before it is placed into service.

Some stations have a minor characteristic sound on their
signal that may be difficult if not impossible to eliminate.
Anyone who
has heard a GE Mastr Pro station can recall the distinctive
sound caused by the cooling fan as it spools up. Even the
most
carefully constructed, well-maintained repeater will produce
unusual noises from time to time. A good portion of these
will
eventually disappear; having been caused by some source
other than the repeater itself. Resist the urge to run �up
the hill� every
time that you hear an unusual noise from the machine.
Occasional brief but bothersome man-made noises such as the
mysterious �kerchunk� or �touch-tone musician� are best
ignored; these problems tend to escalate if given even the
most
diplomatic attention. Remember that as the custodian of a
repeater you are responsible for its transmissions; shut the
station off
if you must to effectively limit an on-going illegal
situation.

As a repeater owner, don�t be too critical of your system,
as there always seems to be some user who isn�t quite
satisfied with
the repeater, in spite of your best efforts. Without fail,
someone who uses a low power transceiver will tell you that
your
receiver needs attention, devoid of a moment�s thought to
his or her own miniscule transmitter. I once had a fellow
express
genuine concern about my 2 meter machine�s lack of
sensitivity; at the time he was standing some 30 miles
distant from the 100
watt repeater with a tiny (300mw) portable transceiver.
Likewise you will hear high power mobile stations comment
about your
lack of transmitter power, all the while full quieting into
your receiver. If you use don�t use a courtesy tone,
seemingly everyone
will suggest that you should have one; once it is installed,
there will be a few who ask why it is too loud, too soft or
otherwise
wrong. These almost universally well meant �armchair
quarterback� suggestions are usually made by those who have
never
maintained a repeater of their own, and should be regarded
accordingly. Changes in propagation, caused by tropo ducting
or
other atmospheric conditions can temporarily affect the
range of your repeater; this is a normal, though sometimes
unsettling
condition.

Finally, don�t be surprised if you install a repeater and it
seems virtually un-used after an initial brief burst of
enthusiastic activity.
Everyone will be anxious to try the new machine, and you
will begin to get a picture of its range and quality after a
few days of
fever-pitched use by area hams. Then the repeater may go
quiet, as everyone in range has checked in and knows what
the
machine will do. It takes some time for hams in a given area
to adjust to a new machine, and even more time for them to
realize
that they are welcome to use it, particularly in those areas
that are already served by one or more repeaters. Whether
your
system covers only part of a small town or most of the
surrounding countryside, a properly installed repeater is an
accomplishment that brings satisfaction to the heart of its
designer, and one that any amateur can be justifiably proud
of.

 

 

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