Jim,

Well, let me say this...

I've run window line for years, and will be switching to open wire line, in
part, next year. In a test that I did about 7 years ago, I ran a 1 ft section
of window line across a metal flourescent light fixture, laying right on it. I
could measure no change in SWR and no change in signal strengths using a 40 m
horizontal loop on 40 m. I'd recommend running a test if possible and see if
it makes a difference.

Right now, I run an 80 m loop and run window line all the way to the tuner in
the shack. Only metal is about a foot away, water pipes and heating ducts that
parallel the feedline for about 25 feet. It works so if there is a problem,
it might not be severe and I'm willing to live with it, hi.

73s,

Evan