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Old February 16th 04, 04:04 AM
J. McLaughlin
 
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I can almost echo that experience. Some years ago, while working on an
automated frequency usage project, I noticed a fast drifting signal. It
would key up several repeaters as it drifted through their input
frequencies (in those days of too little use of "PL"). It also caused
havoc with the automated system as it made it appear that frequencies
were being used that were not being used.
I tracked it down to a dispatch transmitter used by a newspaper in
the 170 MHz range. The Motorola people would fix the radio only to have
it start up some time latter. Finally had a scheme where I would call
the radio shop technicians, many of whom were radio amateurs, and say
"guess who is back?"
Because the transmitter's frequency was above most of the Federal
frequencies, guess who it mostly interfered with.
A study a few years latter in a metropolitan area suggested that
oscillating (at an HF rate) of VHF transmitters was much too common.
Since the signals were always drifting, they just presented temporary
interference to any one user who was inclined to pass it off as
just-one-of-those-things.
Be vigilant. The oscillating transmitters are out there. 73 Mac
N8TT

--
J. Mc Laughlin - Michigan USA

"Crazy George" wrote in message
...
Steve:

Sorry to speak of your employer like this, but this is unfortunately a

true
story. I can provide names, dates and times. Doesn't have to be on a
nearby frequency. When Micor series radios were first delivered,

Motorola
told shops not to tune the finals of the base transmitters after
installation (!!!!). There was a brand new Micor high band pager here

which
had a spur on 440 when cold, but not later in the day (sound familiar

yet?).
Drifted through the 440 machine(s) input(s) all morning, buzzing away,

with
also some commercial FM broadcast content also. Two spectrum

analyzers and
3 months were necessary to nail the problem, and a quiet promise to

make
their 400 foot tower about 398 feet shorter one night got them to tune

the
$&*%* thing and fix the problem. They quoted the Motorola directive

to me
when I first contacted them. However, given my reputation, they

believed
the promise and went against Motorola's advice.

--
Crazy George
Remove N O and S P A M imbedded in return address