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Old November 2nd 08, 06:51 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default Coaxial Antenna question

On Sun, 02 Nov 2008 14:00:40 GMT, "Jerry"
wrote:

Hi Owen

Another way of avoiding the math is to use both a Smith Chart and an
overlay of a Z Theta Chart. The problem of choosing line lengths and their
Zo them becomes intuitive. But any "perfect match" does depend heavily on
knowing impedance rather than VSWR, as you know.
The load impedance ploted on the Smith Chart can be assummed to translate
to any impedance on the circle of constant VSWR for any load impedance.
The impedance moves along the line of constant "Theta" on the Z Theta Chart
for a change of Chart Z.
With the overlay of the two charts, it is fairly easy to see what lengths
and Zo will produce the best match.

Jerry KD6JDJ


Hi Jerry,

Your solution is rather exotic for this group, but I have encountered
it in my Metrology days as part of the HP legacy. The method you
described is missing from this article, but it gives the group a
picture of the chart, none-the-less:
http://www.hpl.hp.com/hpjournal/pdfs...Fs/1950-04.pdf

73's
Richard Clark, KB7QHC