"Rick" wrote in
:

....
Tracking the source on 80m seems impossible.
I made a 2 ft square loop antenna, which has some directivity but the
noise level using it seems to not change
much as I travel the highway.

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.

The nulls will not be as deep, and not ideally located if the feedline is
also part of the antenna, ie if the loop is not well balanced. So much so
that common mode current effects may render the antenna fairly useless
from a directivity point of view.

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

Realise 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.
Nevertheless, it should be relatively easy to locate the cause of the
emission.

From a practical point of view, I have used a small loop and portable
receiver for locating and measuring emissions from BPL over HF, and noise
due to fautly transformer bushings, cracked insulators etc. Worked a
treat for me. One loop is described at
http://www.vk1od.net/antenna/SmallUn...Loop/index.htm .

Owen