Sal,

A capacitance hat allows you to drive your car into the garage without
breaking off a whip of 15 feet equivalent height.

A capacitance hat loads a short vertical without suffering the loss in
a loading coil.

To calculate capacitance of a hat, above an antenna of given height,
with N spokes of given length, surrounded by a halo, plus resonant
frequency, download program TOPHAT from website below.

The program also calculates L and C values of the tuner. The whole
job can be done in a couple of minutes.
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Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
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