Ed, I am giving you information that is not sufficient to solve the
problem.

Nevertheless, I defer to your opinion.

Read my earlier caveats about my reading of your limited information
and
interpretation in a model.

It is apparent to me that we have not been communicating effectively.
I did leave out some info, such as the wire type, ( #18 stranded and
insulated) and the size of the flat metal roof ( can probably be treated
as infinite given its size), but only because I knew the basic losses
due to antenna size itself ( non-resonant ) would be so huge as to mask
any much smaller effects of these other items.


Freq VSWR at feedpoint (RG8/U)
3.98 959
5.4 115
7.2 34


My thanks on the above. That is something basic I can give to the
operators of this station to convince them we need to change the antenna
system. ( Giving them complex impedance figures, etc, would not fly with
that group!)

It is also obvious I need to get EZNEC. Soon as I have time to play
with it, I will download the freebie version for starters. I've seen too
much discussion here on this group not to realize it is worthwhile to
have, even if only occasionally used.


Ed K7AAT