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Old April 11th 06, 06:37 PM posted to rec.radio.amateur.antenna
David G. Nagel
 
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Default Current across the antenna loading coil - from scratch

Tom Donaly wrote:
Richard Harrison wrote:

Tom, W8JI wrote:
"I take it you are saying you think current can flow two directions at
the same instant of time in a conductor through radiation and resistance
without a shunting impedance, conservation of charge isn`t important,
and Maxwell`s equarions are wrong."

That`s the wrong take.

Maxwell works for me even if there is no aether.

Anntennas work in free space without a ground but it is hard to
duplicate free space conditions at high and lower frequencies here on
earth.

Every standing-wave antenna has a reflection caused by an impedance
discontinuity at wire`s end. At this point, a reflection begins its
travel back toward the generator. By the time the reflection arrives at
the generator, every point on the wire has current flowing in both
directions simultaneously. No shunting capacitance to earth or anyplace
else is needed to conserve charge. The wire is self-sufficient.

Radiation resistance is a convenience defined as the resistance which if
placed in series with an antenna would consume the same power that the
antenna is radiating.

At every point along an antenna with a reflection, current is flowing in
two directions at the same time.

Best regards, Richard Harrison, KB5WZI



Completely wrong, as usual. There is nothing in the natural world
that can double itself and go two opposite directions at the same
time. In order to do so it would have to violate the principle of
the conservaton of charge. At any instant, the charge at a point
has to be going either one direction or another which you can
confirm using the wave equation which Cecil doesn't understand
any more than you do. Superposition is a fine principle, but
like any intellectual tool it has to be understood to be used
properly.
73,
Tom Donaly, KA6RUH


Tom

Have you ever sloshed water in a bowl? If you had you would have seen
wave forms going in both directions. First the initial wave crosses the
bowl then reflects off the side of the bowl and returns in the opposite
direction.
This is the same as an EMF wave in an antenna. No violation of any
principles of conservation, in fact it is demanded of the principle.

Dave WD9BDZ