[TenTec] Trading radios

[Jim Allen]

"Ain't no such thing as a ground loop."

Really?  I've been reading about them for decades, in dread, find a whole
long list on Google about ground loops, and all sorts of ground loop
isolators offered for sale by reputable merchants.

Could it be that the "ground" provided by the electrical system and the
"ground" provided for lightning protection are not at the same "ground?"

"That's a very poor choke, because it's purely inductive. A good choke
should be RESISTIVE."

This idea comes from a QST article on Balanced Tuners in February 1990, by
Rick Measures, AG6K, which has been spoken of with favor in many places.
He lists some pros and cons with using ferrites, and air core chokes.

"A connection to earth is NOT part of a solution to RF in the shack
problems, nor does it make antennas work better. it only matters for
lightning protection, which IS important."

Of course, I did not provide this information as a solution to the ground
loop problem, merely to help visualizing the set up here.  It might be
quite important or completely irrelevant to the eventual solution, but I
don't know how to judge that.

"Notice that I said a BALANCED antenna. Un-balanced antennas create lots of
common mode voltage (and current on the line) that CAUSES the sorts of
problems you are having."

I suppose a 130' center fed dipole is balanced.  What about a vertical
monopole?  The suggestion was to use a 4:1 UNUN (not a BALUN) for multiband
matching.  Does this imply unbalanced?

Why put the choke at the feedpoint?  Why not on the shack side of the
remote tuner, after the tuner transforms from BALanced to UNbalanced?

I would like to understand these things, eventually.

73 de W6OGC  Jim Allen