On Thu, 27 Jul 2006 21:43:15 -0700, "Sal M. Onella"
wrote:

I know a capacitive hat (or capacitance hat) lowers the resonant frequency
of a whip by electrically lengthening it, but by how much?

Hi OM,

The hat replaces roughly double its length in height - or so goes one
proportions of one magic formula. So, for your example of:
a 35-foot whip that had a capacitive hat. The hat was a five
foot diameter ring of #10 wire with four spokes off the top of the whip.
hat would say it is equivalent to a 40 foot radiator (35 + 2 · 2.5).
I've often wondered why anyone would go to the trouble to wrestle with
the mechanical details of keeping a top hat aloft, when they couldn't
manage what would be 5 additional feet of whip in this case. Top hats
built out of guys is another story, but free-standing hats seems more
like adornment than being necessity driven.

You may note this doesn't come even remotely close to resonant for
1520 KHz - if that was the implication in your posting. Further, it
would be an amazing top hat that could for a 35 foot whip.

73's
Richard Clark, KB7QHC