Loading Coils; was : Vincent antenna
Cecil Moore wrote:
A loading coil is not an ideal
transmission line and its "current maximum" is not
caused by standing waves.
It's probably true that ideal transmission lines don't exist in any
form. The standing wave in question has both a minimum AND a maximum,
whose locations are determined by the relative phase and amplitude of
the forward and reflected waves at each position.
The "current maximum" in
the coil is caused by adjacent coupling between the
coils and does not occur at a purely resistive point.
How do you propose that this occurs without having an effect on the
forward and reflected waves which comprise the standing wave?
Although not shown, the
voltage at the current maximum in the coil is not
in phase with the current so in this case, the
"current maximum" is not a pure resistance, is
not the current anti-node point, and is not the
resonant point. The current at the bottom of the
antenna is in phase with the voltage and the feedpoint
impedance is purely resistive.
It would be better if you provided some sort of demarcation between
the well known facts and the pensive speculation in your posts. :-)
The coil puts a hump in the current which causes
the current envelope to deviate from sinusoidal.
What does the IEEE dictionary have to say about 'current humps' I wonder.
73, ac6xg
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