[RFI] Line noise vs Frequency

[Charles Plunk]

Interesting you would bring this up. My current 120hz target peaks at 
roughly 19.5mhz. Falling off below roughly 10mhz to where its almost 
insignificant and goes up to about the 2 meter band where its very weak 
with directional antennas. I started hunting it after the power co fixed 
my primary source back in the spring. I had isolated to a ~3' area of 
ground wire stapled to the pole, I think. 7.2kv 3 phase pole with lots 
of hardware so not easy to tell with ultrasonic dish. I wanted to do 
some more investigating but then came the high Tennessee humidity for 
the summer and the target has been >98% absent.

I greatly suspect it will return more frequently with the lower humidity 
in late Sept/Oct forward. A few days ago the humidity got down to close 
to 60% and it returned for a few hours.

Its on a pole in my back yard thus very close in proximity to my 
antennas. As to why the peak, I would be interested to know also. Some 
of the utility hardware of such a length it resonates on a certain 
frequency? Just a guess.

One thing is for sure, an open mind is essential to hunting this stuff, 
lol. My biggest surprise is finding 3 sources on 2 poles so far related 
to the stapled ground wire. The one they fixed I actually saw it arcing 
with binoculars. Another due to a crepe myrtle growing around the pole 
(and stapled ground wire). Cut the limbs off it and it was gone. And 
this third one that appears right now to be related to the stapled 
ground but that has yet to be resolved.

Chuck

W4NBO



On 8/8/21 7:24 AM, Pete Smith N4ZR wrote:
> A (probably) dumb question:  I have a severe line noise to my west. 
> For some reason it is manageable on 20, much worse on 15 and crippling 
> on 10.  These subjective descriptions are confirmed on my S-meter. Why 
> would this be happening, and does it offer any helpful clues to 
> finding the source?
>