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Old February 25th 06, 03:21 AM posted to rec.radio.amateur.antenna
Richard Clark
 
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Default nec simulation - unexpected result ??

On Fri, 24 Feb 2006 20:12:42 -0500, Amos Keag
wrote:

If the feed is 'changing the resonance' then there is a problem with the
feed!!


Hi Amos,

Where do you see that in the data? Or are you mis-interpreting the
distinction between the choice of the feed point with attaching a feed
line? The model distinctly lacks a feed line, or may be presumed to
have a feed line that is completely isolated from the antenna(s).

The wire retains its original fundamental resonance - within a couple
dozen KHz, a negligible difference. The remainder of its resonances
are strictly governed by the selection of the feed point's position
along the length of the wire. I incorrectly argued for a lower Z with
Dan earlier. By and large, moving away from the center raises the Z
(principally R at resonances above the fundamental).

73's
Richard Clark, KB7QHC