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Old November 30th 07, 04:25 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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First recorded activity by RadioBanter: Jul 2006
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Default opinions on an antenna idea

On Fri, 30 Nov 2007 08:06:02 -0800 (PST), James barrett
wrote:

Would it behave like a 136 foot dipole, or
would it behave like a shorter dipole?


Hi Jim,

At the right frequency, the right height, and at night it might act
like an aeronautical beacon. Or given the season, it might provide
sufficient light to be used as the star of Bethlehem decoration.

But if you want even more outlandish claims for performance (I like
the part of adding capacity hats to lower noise), add the google term
"Gaussian array." Good luck with making any sense of what passes for
construction hints (you will have to wade through a lot of window
dressing to find them first).

OK, now for some real technical content:

The first order of business is in the description for a tight wound
coil. The proximity of windings drives efficiency down. Open up the
windings. The short physical length of a radiator drives the
efficiency down. Extend the winding pitch further. The short
physical length of a radiator demands closer attention to matching
(lower efficiency again). Lengthen the radiator. Using the entire
length of a radiator to support a coil drives down the radiation
current (this is really a combination of the earlier problems, but it
is way cool to say it sucks again). Lengthen the radiator.

The advice is sufficient for a receiving antenna, hence the source of
Radio Habana Cuba's recommendation. It is especially poor for
transmitting, hence its absence in Radio Habana Cuba's transmitting
antenna farm. Those two clues should be sufficient.

73's
Richard Clark, KB7QHC