[RFI] Can you identify this interference?

Alex kr1st at amsat.org
Thu Jan 22 09:22:21 EST 2004

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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