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

Dave Cole dave at nk7z.net
Sat Apr 30 20:04:10 PDT 2011


Correction to number 1...  Make that 120 HZ, not 720.  Or twice sixty
hertz.  That I understand I think...

This looks like a power line sparking, or a motor...  Can someone with
more experience assist in IDing this?
Dave
NK7Z


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On Sat, 30 Apr 2011 19:47:51 -0700
Dave Cole <dave at nk7z.net> wrote:

> Hi,
> 
> Well, I know what it isn't!  I thought I had a noise pinned down to a
> house.  The noise at the house is gone, and the noise at my place
> persists...  All of 40 meters is shot.  It is frequency specific
> however, starts around 6.5 MHz, and ends around 9.5 MHz, slow build up
> and drop as I sweep. Used a BWD-90, broadband antenna to verify it was
> not my antenna BW causing the tight frequency range, and a portable SW
> radio, it really is between those frequencies... 
> 
> I took several measurements of the audio portion as viewed by my
> computer on the radio audio output, and I found some very interesting
> things...
> 
> 1.  There is an audio pulse every 720 Hz or 12 times 60.  This makes
> me think it is power line related, although I have no idea why 720
> Hz... 2.  The noise is on 7 X 24 X 365
> 3.  It appears to be spark like in nature, see expanded and wide views
> of waveform as captured on an O-Scope.  Can someone verify this
> assumption please?
> 
> Can anyone suggest what this might be?  See:
> http://db.tt/eSA0bq4
> for images, and a sound cut as an MP3. 
> 
> Thank you,
> Dave
> NK7Z
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