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[RFI] Horrific Ugly Noise, thought I had it!

To: "'Dave Cole'" <dave@nk7z.net>, <rfi@contesting.com>
Subject: [RFI] Horrific Ugly Noise, thought I had it!
From: "RFI Services' Michael Martin" <mike@rfiservices.com>
Date: Sun, 1 May 2011 12:52:12 -0400
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
This will explain a little more about arcing sources.
If you have a fixed gap, arcing occurs every half cycle, most of the time.
As the voltage rises across the gap and the gap becomes stressed to the
point of breakdown, the arcing starts at the voltage needed to jump that gap
and continues through the peak voltage to the same level as the starting
voltage, then the arcing stops. This is during 1/2 of the cycle. As the
cycle starts on the negative side the arcing starts again at that same
voltage and the pattern repeats itself. 
The pattern you are seeing, a single spike, if it were power line the
pattern would indicate a very large gap or a lower voltage across the gap.
This means the voltage across the gap is just high enough to only arc once
at peak voltage. 
The voltage drops too fast and you would not see a trail of smaller spikes
in an arc. Remember we're talking about 120hertz, pretty fast.
Go to the ARRL web site and order the book by Marv Loftness, it's great and
gives information in detail that you will appreciate.
This is for example:
These patterns are all as viewed using the audio from a receiver into a
scope and viewing one full cycle. The caused is induced voltage into loose
hardware on a 7kv distribution pole. The number of spikes represents the
number of discharges per half cycle which are determined by the gap size or
the voltage level across the gap. The height of the spikes determines the
signal level received. If the number of spikes changes, that would be caused
by the gap size changing which isn't uncommon on a utility structure.

    llll     llll       this is a 1mm gap 12 inches from the primary
conductor
     ll       ll        this is a 1mm gap 24 inches from the primary
conductor
  llllll    llllll      this is a 1mm gap 6 inches from the primary
conductor

     llll    llll       this is a 2mm gap 6 inches from the primary
conductor
      ll      ll        this is a 2mm gap 12 inches from the primary
conductor
   llllll   llllll      this is a 2mm gap 3 inches from the primary

For a more thorough explanation, which is possible, you'll have to attend
one of my workshops. Which by the way your power company should be
attending.
Right now I have more important matters to tend to, my grandson wants me to
play!

I'll be in Oklahoma all this week solving these types of problems.
Best wishes,
Michael C. Martin
RFI Services
6469 Old Solomons Island Rd
Tracys Landing, MD 20779
www.rfiservices.com
240-508-3760

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