Re: [RFI] Yagis and DFing_Being as we are on the subject

[Charles Plunk <af4o@twc.com>]

Being as we are on the subject :-) You guys have skillfully helped me in 
the past locate some awful nearby 120hz sources and I appreciate it.
I have been casually tracking a 120hz source since the summer. Casually 
because it is distant (other side of the neighborhood ~ 1800' away) and 
I can mitigate it with noise blankers etc ~90% of the time. I located it 
to within 3 power poles. All 3 have bell end insulators and a couple of 
the spans are slack. Its likely old hardware probably 60's (I have good 
reason to believe this). Single phase 7.2kv (only other on the poles is 
cable/phone). Houses all around.
I did match the pattern by re-transmitting the station audio. But cannot 
determine, with HT/Yagi's, which pole for sure its coming from as its 
well conducted throughout all 3.  And it maybe more than 1 of them. Up 
close I can hear it on 440mhz on all 3 poles. Not enough real estate 
without trespassing to back far enough off to get out from under the 
lines to triangulate which pole better (if it is a single pole or not 2 
or 3).
I did request they replace the insulators on all 3 poles (and tighten 
the spans) as they are about the only hardware on all 3 poles on the 
7.2kv. That was back in the summer. Have not heard back from them (and 
they have not done last time I was by there) and I have not pressed it 
admittedly.
Should I press them to do all 3 or try to isolate to a single pole or 2? 
Even using attenuator's I doubt I will be able to determine with 
certainty which pole as all 3 had a close signal strength. I have not 
tried the flag antenna. I could try that and attenuators to isolate 
before I contact them again. Or setup something higher in frequency. 
Unfortunately could not hear anything with ultrasonic. Any other 
suggestions?
Thanks

Chuck
W4NBO

FT60 on AM mode

FT817

2 meter handheld yagi

440 handheld yagi

QST homebrew ultrasonic dish (has worked well on other sources)







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