MGFoster wrote:
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What do you mean "maintaining good contact to it"? The copper tape
adheres well & doesn't move. The foil is secured in place by the
packing tape (it completely covers all of the foil surface and copper
tape connections). The tubes propeller a bit in the wind, but I don't
think that causes any disruptive flexing of the foil; at least not
enough to cause the soldered/taped connection to break/discontinue.

I couldn't xmt on 40M cause of the high SWR, but I could rcv &, except
for the noisy conditions, it sounded fine.

Thanks for your comments.

The instant aluminum comes in contact with air, an oxide layer forms on
it. The oxide layer is a hard, brittle ceramic which is an excellent
insulator. Making electrical contact to aluminum requires breaking
through the oxide to the metal underneath. This causes broken pieces of
the oxide to dig into the aluminum. If pressure is maintained and no air
ever strikes the aluminum again, the contact will remain sound. That is,
in fact, how aluminum house wiring is (properly) handled -- a high
pressure contact, with a generous amount of grease to prevent contact
with air.

If your contact jiggles a bit in the wind or for any other reason, the
physical contact in various places will be broken at times. Each time,
more oxide is formed and, when pressure is reapplied, it breaks and gets
pushed into the aluminum. Eventually, you have a surface that's mostly
shards of oxide and little or no metallic aluminum. (This is also why
tin plated contacts always inevitably fail.)

In addition, copper and aluminum form an electrolytic cell. So if any
moisture is present, corrosion of the joint will occur and contact will
eventually become bad or lost altogether.

That's what I mean by the difficulty of "maintaining good contact". Your
system will work fine. For a while.

Roy Lewallen, W7EL