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Old January 22nd 05, 05:28 PM
Cecil Moore
 
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bbnn wrote:
Why not a 7/8 wave antenna?


OK for a horizontal antenna. Causes unwanted high-angle
radiation in a vertical.

Why does a 5/8 wave antenna need a loading coil and a 1/4 wave antenna
doesn't?


A 1/4WL vertical with a ground plane is resonant. A 5/8WL
vertical is not resonant and requires some sort of matching.

Is there such a thing as a 1/2 wave whip ant. fed at the bottom?


J-Pole is a good example. The bottom 1/4WL of a J-Pole is
the matching section.

Are there other sizes of whip antennas?


Any length of vertical whip up through 5/8WL will work well
if you can deliver the RF energy into the antenna. For
practical matching purposes, whips without internal loading
are usually limited to about 3/16 wavelength. I've used a
13 ft. whip, resonant on 17m, on 20m with an autotuner and
it worked well. On 40m, it was a good S-unit down from my
homemade bugcatcher.
--
73, Cecil http://www.qsl.net/w5dxp


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