"Owen Duffy" wrote
...

If you study the pattern of a small loop antenna, it has a pair of deep
nulls. These are the most useful for locating the direction of the
source.

A possible explanation for why the 80 meter noise couldn't be nulled is that
at most I
was 100 yards from the line and the noise was radiating from all along the
line. That's what it
seemed to be. On the broadcast band, the loop was easily able to locate the
direction of
the NYC radio stations from here in central NJ so I think the antenna was
doing it's job..


You did not mention the measures you took to assure loop balance /
insignificant common mode current.

My loop was a square made out of ribbon cable. 1 foot on a side, 7 turns.
The ends of the multiturn loop were attached to a broadcast variable cap.
One turn of the same ribbon cable was the coupling loop, which I connected
to a 6 ft length of RG58 with a BNC connector. The cap peaked the signal or
noise up
nicely.

Realize also that you may be trying to locate the cause of the emission,
but the loop (properly constructed and used) leads you to the radiation
source, and the power lines are very large and very effective antennas.

Understand, that's the conclusion I came to and the reason I switched to
10m-70 cm to
home in on it.


From a practical point of view, I have used a small loop and portable
receiver
The photo on that web site is essentially what I built, except mine was
multiturn, and had no balun.
I was listening at 2 MHz.

Rick