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Old April 1st 06, 02:06 PM posted to rec.radio.amateur.antenna
Cecil Moore
 
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Default Current through coils

Ian White GM3SEK wrote:
It's a simplification of any real-life coil - but loading by
pure-and-simple lumped inductance is also a vital test case.


It only tests the validity of the lumped-circuit model. It does
NOT test the validity of the real world. Testing the validity
of the real world is best left to metaphysicians, not engineers.

This form of loading is the simplest imaginable. If a theory about the
behaviour of loaded antennas fails to give correct results for this very
simplest test case, it cannot be valid... and all the further
elaborations about real-life coils will not be valid either.


Whoa there, Ian. You are confusing cause and effect. If the lumped
inductance fails to give correct real-world results, then it must
be abandoned in favor of a more powerful model, e.g. the distributed
network model.

You are making my argument for me. Do you really believe a 2" dia
x 12 inch coil has 100% flux linkage between coil 1 and coil 100?

But it is an absolutely basic fact that the physical world
does NOT change its behaviour according to the way we choose to think
about it.


Exactly! Choosing to think about an inductance as "lumped" does
NOT change the behavior of the coil. The behavior of the coil
is what it is. Choosing to think about it as "lumped" is often
an over-simplification, a fantasy existing only in someone's mind.

For the avoidance of doubt (as they say in Scottish legal documents):
It certainly IS possible to analyse and predict the behaviour of
coil-loaded antennas in terms of travelling and standing waves. My
objection is specifically against Cecil's method, which is provably
incorrect.


The distributed network model, a superset of the lumped circuit
model, is "provably incorrect" after being accepted and tested
for more than a century??? By all means, please prove it incorrect.
That should be very interesting - overturning a century of
acceptance.
--
73, Cecil http://www.qsl.net/w5dxp