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Old November 10th 03, 07:31 PM
Roy Lewallen
 
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The feedpoint impedance without the inductor was 35 - j185. The inductor
was 0.6 + j192. Sorry, I had left it up to you to add the two together,
to get 35.6 + j7 ohms.

It would be nice to have something better than a ballpark value, since I
think I can get the ratio of output to input to within a couple of
percent or so, and resolve two or three degrees of phase shift. Anything
more precise than that, though, I won't be able to resolve anyway. Which
is why the next test might be better, since you'll be choosing the
inductor size to make the shift very apparent. Won't you?

So what's your new, more precise prediction of the output:input current
ratio (magnitude and phase) for the system I did measure?

Incidentally, I've now also made a measurement using the same system on
the bench, substituting a series RC with the same Z as the antenna
feedpoint for the antenna. You've stated that you expect to see a
difference between this setup and the antenna (the former being "lumped"
and the latter "distributed"). Do you, Yuri? How about you, Richard? If
so, what should I be seeing for the ratio of output:input current in the
lumped setup?

Roy Lewallen, W7EL

Cecil Moore wrote:
Roy Lewallen wrote:

and Cecil's, that the output current should equal the current, both in
phase and magnitude.



Hold the presses! That was a rounded off ballpark value.
You haven't told us what the feedpoint impedance is yet
so an accurate estimate is impossible so far. Is the
feedpoint impedance 35.6+j8? Is that the impedance into
which you are shoving one amp?


 
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