Thread: Capacitive Hat
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Old July 30th 06, 06:52 AM posted to rec.radio.amateur.antenna
Sal M. Onella Sal M. Onella is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 442
Default Capacitive Hat


"Reg Edwards" wrote in message
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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.


That's outstanding! I see the original antenna was only about 15% efficient
and the capacitance hat improved it by about 2 dB. I will play with that
program. Thanks.

"Sal"
(really KD6VKW)