[RFI] Can you identify this interference?

michael.findley at ni.com michael.findley at ni.com
Thu Jan 22 08:44:17 EST 2004

This also looks like a dry cracked insulator on the power lines. This type
of noise shows up after a good dry spell. If it rains than the noise should
go away until it dries up again. If this is the symptoms then good luck
with the utility company because their responsiveness is slower than a 8086
running win 2K.
Hope this helps,
Mike, NCT

                      <kr1st at amsat.org>        To:       Pete Smith <n4zr at contesting.com>                                              
                      Sent by:                 cc:       rfi at contesting.com                                                            
                      rfi-bounces at conte        Subject:  Re: [RFI] Can you identify this interference?                                 
                      01/22/2004 08:22                                                                                                 
                      Please respond to                                                                                                

Hi Pete,

Pete Smith wrote:

> It looks and sounds to me like at least 2 electric fences at differing
> signal strengths and with their "tick" interval slightly different.  Is
> that possible, given your QTH?

That was my first thought, too. I thought maybe someone put something up
for their dogs. I'm not in a rural area and there are no farms nearby,
and no one keeps animals except the usual pets. The yards in this
neighborhood are not big enough for that. :(

I did cut the power to the house, and checked everything that runs on
battery power, to no avail though. I also wonder if the noise gets
propagated though the power lines as the interference is strongest near
the house wiring. But that may be just the house wiring acting as a
large antenna that couples its energy into the whip of the portable
receiver. Same thing happens when I hold the whip near the chain link
fence of the neighbors.

I also drove around in the neighborhood with a scanner (136 MHz, AM) and
a portable shortwave receiver, but I can't find any hot spots. In fact,
it disappears just a 1 or 2 houses down the road from me. I'm inclined
to think it's something that radiates a rather weak signal and is close
to me. Hopefully I get some time soon to do some DFing with the scanner
and a VHF Moxon.

Thanks for the suggestions and 73,
--Alex KR1ST
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