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Re: [RFI] My power line noise problems, revisited (Warning, thisislong!)

To: "John Pelham" <john@radiophile.com>, <rfi@contesting.com>
Subject: Re: [RFI] My power line noise problems, revisited (Warning, thisislong!)
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Thu, 5 Feb 2004 20:14:46 -0500
List-post: <mailto:rfi@contesting.com>
> What I learned that morning, in a nutshell, was that it's amazing that any
> power can be distributed at 14400 without problems.  Arcing, as indicated
> our ultrasonic testing, came and went for the most capricious of reasons.
> For example, if a piece of debris were to strike one of those thick
> cables that jump power from one insulator on one side of a pole to the
> other, it might get unraveled or "unstranded" slightly.  I'm talking about
> just a tiny fraction of an inch of strand separation, and just for a short
> length, say two inches, of cable.  Just these separated strands would arc
> merrily, despite being fully connected just one inch away.  The tiniest
> hairline or speck of debris on an insulator would cause arcing.  This
> just loves to arc.

If he told you that, then he is exaggerating the problem a great deal. First
of all, it would almost take a sledge hammer and crowbar to knock a strand
"loose" from the wire bundle. Second, that would NOT cause an arc. Neither
does a speck of dirt or even a good sized chunk of Buzzard crap on an
insulator. Almost all populated areas use 14,400, inclusing the line right
down the street in from of my house. My noise level is zero. It is zero in
rain, ice, wind, dust (I live on a dirt road).

The reason my noise is zip is there are no loose bell insulators, there are
no loose tie wires, the hot clamps are tight, and the transformers have the
connections all nice and tight. No one ran staples through the poles that
almost touch the insulator mounting plates, and the hardware either makes a
firm connection or it doesn't.

I did have some noise from about a mile away, but one time it was a wire
just laying on a transformer post and another time a hot clamp backed off
and was arcing inside.

You can't reliably find 6 meter noise by listening on another frequency,
including the audio spectrum. You need to start at the house (making sure
the house is clean) and work out in the direction of noise listening on 6

> reduction in line noise in my ham shack later.  It was apparent (it
> had been clear to me already) that there were _many_ different sources of
> noise affecting my radio reception.

Now that could be, but I'd bet it is improperly installed hardware or
something grossly defective (like slack spans in lines using pinned
insulators, allowing the pins to corrode and arc).

> "on my side" regarding his willingness to work toward a solution.  I don't
> want to alienate him by suggesting he get help.

That might be your only option.

> Also, does anyone know if is really suitable to distribute power in a
> residential area at 14,400 volts?  From my experience, this stuff will
> stop arcing.

Sure, it is fine if the hardware is OK and installed properly. I'm sure
other will have some input, but my opinion is the power line guy is never
really finding the actual problem or problems. He is just shot-gunning a
complex system and wasting time and money.

What scares me most about your story is the tale that a "parted strand" that
is attached two inches away can "arc" and cause noise. While it is true that
sharp protruding ends sticking out into air greatly increase the voltage
gradient, they very rarely make any noise! The description you gave, if that
is indeed what the power line fellow meant to say, really bothers me.

73 Tom

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