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Re: [RFI] Power Line Noise

To: <rfi@contesting.com>
Subject: Re: [RFI] Power Line Noise
Date: Thu, 25 Feb 2010 22:33:35 +0000
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
Write down the numbers on the pole, the street address it is nearest to, and
the nearest cross street/intersection, then call the electric utility
company for the area.  

David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net

> -----Original Message-----
> From: Kimberly Elmore [mailto:cw_de_n5op@sbcglobal.net]
> Sent: Thursday, February 25, 2010 21:01
> To: rfi@contesting.com
> Subject: [RFI] Power Line Noise
> K3LR suggested that I submit this here because there are a lot of you that
> know a lot more about this than I do. So, here goes:
> Recently, I've noticed some pretty severe, intermittent power linenoise at
> my QTH. It had previously been a marvelously quiet place for
> radio, but over the past month or two, that has changed. I had it
> againthis morning and so decided to do some sleuthing.
> I live E of Norman, OK, in the center of a section bordered by Robinson on
> the S side, 48th St on the W side, Rock Creek Rd on the N side and 60th St
> on the E side.
> Both OG&E and OEC lines run down all roads. On Robinson (the S
> side) the OG&E lines are on the S isde and the OEC lines are on the
> N side. The OG&E lines run 35 kV -- I don't know what the OEC lines run.
> My neighborhood is served by OG&E and all wiring is under ground; step
> down transformers are above ground on concrete pads.
> Here are the details:
> I cannot detect the noise on any band above 40 m, but it's clearly
> apparent on 40, 80 and 160 m. My Orion II noise blankers are ineffective
> on 40 m (both the software and hardware noise blankers) but are very
> effective on 80 and 160 m. Because I cannot hear it above 7 MHz, I'm
> pretty sure that the source is not emanating from a neighbor's house or
> from a nearby step-down transformer.
> Using my K9AY loops, I can detect the noise when the loops favor either NE
> or SE, but not whenthey favor NW or SW. Thus, the source is either to my N
> or my E.
> Using my 2 el 40 m beam, I found sharp nulls with the beam pointed either
> Nor S (probably nulls off of the sides), and less noise when the beam is
> pointed W than when it is pointed E (~S9+25 dB pointed E, ~S9+15 dB
> pointed W). So, F/B ratio favors a source to my E.
> I then got in my car, tuned my mobile rig to a quiet frequency in the
> aviation band (118.0 MHz) so that I could use the AM detector at VHF and
> started driving E along Robinson to 60th street. I heard nothing of
> substance along Robinson. I turned N and drove along 60th and found a
> strong noise source. I double checked my traverse and found the same spot
> three different times. It was considerably weaker from across the road
> than it is next to the pole. There is a private drive going E from 60th
> street, away from the offending pole. Driving down it 100 feet diminishes
> the signal strength significantly. The ground wire for the pole appears
> intact at the base.  I am absolutely positive that I have identified the
> pole holding the faulty hardware. I could see nothing obviously loose, but
> the culprit is most certainly there.
> The noise is intermittent: it starts and stops abruptly as the wind
> blows,though I can detect no obvious correlation to wind changes and the
> starting and stopping of the noise.
> What now? Whom do I contact with my information?
> Kim Elmore, N5OP
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