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Old January 30th 04, 08:12 PM
Jim Kelley
 
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Cecil Moore wrote:

Tdonaly wrote:
In order to show that an inductor can
be treated as a transmission line, in the way you want to do it, you
have to show that your inductor has an exponential current gradient
along its length when it's terminated in a certain impedance.


All I have to do is point to W7EL's and W8JI's measurements that
show a current gradient along a real world loading coil in a standing-
wave antenna. The current gradient is illustrated by Kraus on page
824 of _Antennas_For_All_Applications_, 3rd edition.

You are failing to take into account that the net current in a standing-
wave antenna is the phasor sum of the forward current and reflected
current, i.e. the earth is not flat.


Right, Cecil. But you need to make it clear that you're not talking
about a traveling wave gradient.

It's a simple matter to measure the phase delay across a coil. The
gradient is simply the result of the phase differential across the
inductor and its effect on the two superposed waves traveling through it
in opposite directions. But the resultant is a STANDING WAVE, with
magnitude a direction at all points along the antenna, transmission
line, whatever. But the standing wave itself does not move or 'flow'.
This idea that more current is flowing into one end than flows out of
the other is really not particularly illustrative of anything. It's
just creating misunderstandings, and a reluctance to accept an otherwise
valid argument.

73, Jim AC6XG
 
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