TF3KX wrote:
I have been considering a vertical setup on the top of my galvanized
sheet metal roof and using the roof as a ground plane. My brief tests
so far indicate that the performance of such a setup does not deliver
as strong signals to my RX as my simple inverted-V. Nevertheless, my
roof is only 2 years old, still in good condition and with well
overlapping sheets.

There may be various reasons for this, but it has occurred to me that
the galvanized roof may not be such a good RF-conductor. Due to the
skin effect much of the current would run in the zinc coating, for
which I do not have much information on as far as RF-conductivity goes.
Does anyone have a comment or suggestions on this?

By the way, I am going to try to lay additional wire radials (aluminum
welding wire) on this roof, which is the subject of a post I just sent
out before this one.

73 - Kristinn, TF3KX

Hi Kristinn,

Effectively the radials will not even be seen by the Antenna because of
the large metal surface area of the Roof. As Reg Suggests the only way
you may improve the situation is to attach radials to the roof edge and
have them extend the length of the ground plain system. A better method
under the condition you have stated may be to be sure the bond between
roof panels is RF/electrically good and add radials to by connecting
them to the roof panels at the edge of the roof. You do not mention the
Frequencies of Interest. Aluminum on Zinc is not a good Idea. There
will be interaction and it will create noise on RX in short order.

you would be better off raising the radials off the roof by some
distance if you decide to go that root.

hope this helps. 73 Dave, KC1DI