[RFI] Tracking the Noise

EDWARDS, EDDIE J EDWARDS, EDDIE J" <eedwards@oppd.com
Mon, 5 Oct 1998 16:28:01 -0500

> technicians from two
> different utilities who told me to do PRECISELY this when I was
> searching
> the cause of static here.  No, the power company would not locate the
> problem for me.  I had to diagnose it to the pole, then call them in.
> The
> local utility actually asked ME if I knew WHICH piece of hardware ON
> the
> pole was causing the problem so they would NOT have to diagnose it any
> further.
	[K0iL]  This is kinda funny, but sad at the same time.  To
diagnose which component on the pole is causing noise, we use an
ultrasonic (UT) detector with a parabolic dish.  These typically cost
$5000.  A pole mounted RF sniffer will work too, but not as well.  And
only the line crews can use the pole sniffer.  We used the sniffer
before we got the UT device.  We usually would just re-work the whole
pole (tighten all hardware, replace worn stuff) once we determined it
was indeed noisy.  Very time consuming and sometimes not even needed to
solve the problem.  

> What alternatives are available, BEFORE contacting the utility?  I'd
> like
> a better way to ferret out the cause.  Any suggestions for some way
> better, not just different?
	[K0iL]  I think you're asking if there's a better way to find
the pole than an RF noise trace.  Yes & No.  The only way to trace RF
noise I'm aware of is to physically trace the RF noise to the noisey
poles.  However, if you have access to a permanent Storage Scope, try
taking a shot of the noise you're hearing at the ham shack using the
shack antenna(s).  Then start searching using the rising freq method I
described earlier.  When you find a noisey pole, compare the wave
patterns to see if they are close (at the same freq of course).  RF
Engineers sells an RF locator with a built in storage scope.  I wish we
had one, but they're too expensive!  

	It is still the utilities' responsibility (per Part 15) to clean
up noisey poles (called incidental RF radiators).  It sounds like
deregulation is having a negative impact on this aspect of utility
service.  Now that practically everyone's on cable TV, there is alot
less phone calls coming in for pwr line RFI at the utilities making it
difficult to justify keeping trained personnel up to date on these
problems.  The FCC is starting to enforce the rules once again so maybe
that will help.  

	I hope I didn't misunderstand your question.

	de ed -K0iL


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