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RE: [RFI] Power Line Noise in Indonesia

To: <rfi@contesting.com>
Subject: RE: [RFI] Power Line Noise in Indonesia
From: "Hare,Ed, W1RFI" <w1rfi@arrl.org>
Date: Mon, 19 Jul 2004 12:44:44 -0400
List-post: <mailto:rfi@contesting.com>
The BPL modeling I have done couples energy onto the power lines in the same 
fashion as a sparking insulator. In this case, it appears that the horizontal 
wiring and the vertical ground wires both contribute to the emissions.  

There is also a vertical component caused by the E field gradient at the wire 
vs the lower E field present near the ground. 

Ed Hare, W1RFI
ARRL Laboratory Manager
225 Main St
Newington, CT 06013
Tel: 860-594-0318
Internet: W1RFI@arrl.org
Web: http://www.arrl.org/tis
Member: ASC C63 EMC Committee
   Chairman: Subcommittee 5, Immunity
   Chairman: Ad hoc BPL Working Group
Member: IEEE SCC-28 RF Safety
Member: Society of Automotive Engineers EMC/EMR Committee
Member: IEEE 

> -----Original Message-----
> From: rfi-bounces@contesting.com [mailto:rfi-bounces@contesting.com]On
> Behalf Of Jim Brown
> Sent: Monday, July 19, 2004 9:39 AM
> To: rfi@contesting.com
> Subject: RE: [RFI] Power Line Noise in Indonesia
> On Mon, 19 Jul 2004 12:43:08 -0000, David Robbins K1TTT wrote:
> >Since you say that the noise is better when it rains there are two
> >possible explanations.  First, the insulator surfaces are cracked or
> >have arc damage, in this case the rain is filling the gaps 
> and causing 
> a
> >steady current instead of arcing.  These should be replaced.  The 
> other
> >is that the insulators are dirty.  In this case the arcing is between
> >gaps in the contamination, when it rains the gaps are bridged or the
> >contamination is washed off for a while, once the surface dries the
> >noise starts again.  Power washing can remove contamination 
> without
> >shutting off the line, but must be repeated regularly if you are in a
> >marine or heavy industrial area that contaminates them quickly.  I 
> have
> >also seen some surface treatments that can help prevent surface
> >contamination, but not sure how widely these are available.
> While we're on this general topic  -- one of my pro audio engineering 
> friends has pointed out corona discharge as a chronic problem in 
> coastal areas. Can someone address the mechanics of this problem 
> and arcing at insulators in general?
> I am of the opinion that it is the vertical downlead (running 
> down the 
> pole to earth) from protection devices that does most of the 
> radiating 
> of noise that is coupled from protection devices to this 
> "ground" lead.  
> Based on the height of a typical pole, this downlead is going to be a 
> most efficient as an antenna between roughly 5 MHz and 10 MHz. 
> Thoughts anyone?
> Jim Brown  K9YC
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