> How do you turn an old concrete grain silo into a really useful vertical
> antenna.?
I'd rely on Mr. Faraday's expertise.
Inside a metal cylinder, the electric field becomes zero. When the
time-varying electric field is zero so is the time varying magnetic field.
What that means is this. If you surround the silo with a cage of drop
wires, whatever is inside that cage has no effect on the current on the
outside of the cage, nothing but dead air inside the cage. If that cage of
wires is insulated from the ground and the silo it surrounds, it will be
easy to feed as a monopole.
With four wires, they'd have to be held far out from the sides. The more
wires the closer to the sides you could make the cage and still have it
work. But after all that work, you'd still just wind up with a very fat 50
foot vertical.
> in ladders) and after a year of looking at it I can't figure away to
> readily get to enough spots around the dome to hang a "cage" vertical
> monopole off it using wires.
Then you're stuck. If you can't get at least four or eight evenly spaced
wires hanging off it, you might as well use it to hold up dipoles or plant
a vertical on the dome. .
73 Tom
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