[RFI] Locating Noise - Radiated or Conducted and then radiated

Wendell Wyly W5FL wendell@wyly.org
Sat, 1 Jun 2002 21:20:54 -0500

I have very loud received noise that is about 10 db over S9 on 10,12,15,17,
and 20 meters.  When I plot the pattern using the noise as a constant source
from the 10 meter antenna, 15 meter antenna, and 20 meter antenna, I get
three similar overlaid patterns corresponding to the actual antenna patterns
but all three pointing exactly to 210 degrees and all with almost the same
maximum S meter reading on these five bands.

I am on a rural hilltop location with 20 mile line of sight from a 64 foot
tower. Most houses are on 5 acre or larger sites here.  I assume the noise
is line noise, but have not confirmed that either. Am I looking at the noise
source directly with the antenna or can the exact direction be camouflaged
if the noise is conducted for a long ways and then re-radiated?  Is there an
easy way to determine whether the noise is primarily radiated or conducted.

The noise blanker on the Yaesu 1000MP knocks the noise way down (6 or 7 S
Units)as the noise has a very high peak to average ratio (arc?).