Cecil Moore wrote:
Ian White GM3SEK wrote:
Based entirely on what you yourself have written, I have told you
that you don't understand something.

Unless you can prove you are omniscient, Ian, the problem could
possibly be with your misunderstanding of something, not mine.



It certainly *is* possible to make a correct analysis of a short
coil-loaded antenna in terms of forward, reflected and standing waves of
current.

My objections are only about errors in Cecil's specific attempt to do
it.

This particular problem is a small hole in our jigsaw puzzle of human
knowledge. It would certainly be worthwhile to craft a new piece, and to
have the satisfaction seeing it fit exactly into place.

But jigsaw puzzles have unbreakable rules: a new piece must fit EXACTLY
into the gap that it fills; and everywhere around its edges, the picture
MUST join up EXACTLY. If it fails to fit exactly and in every detail,
then it isn't the right piece.

All the surrounding pieces of existing knowledge about antenna
engineering fit neatly together to make a solid picture. We can see the
big picture, and that we're only trying to fill a very small gap.

That big picture is made up from only a very few primary colors. They
can blend together to give infinite hues and subtleties, but everything
comes from mixing those same few primary colors which DO NOT CHANGE.

The 'primary colors' of antenna engineering are a few fundamental
physical facts that DO NOT CHANGE from one piece of the puzzle to the
next. (Out at the far edges of the puzzle, the advances of 20th-century
physics have shown that classical physics is part of an even bigger
picture than we'd imagined - but in doing so they have confirmed where
the rules of classical physics still CAN be applied. That includes the
whole of electrical and electronic engineering, except for what happens
inside semiconductor devices. Regarding antennas, Einstein's equations
include and clarify Maxwell's equations, and quantify the margins of
error in this area of classical physics. This confirms that antenna
engineering indeed CAN be completely and accurately understood using
classical physics, because the margins of error are too small to affect
any practical observations.)

Returning to this particular gap in the picture of antenna engineering,
concerning short loaded antennas, we can see that it's only a small gap.
It is surrounded by large areas of existing knowledge that interlock
solidly and completely. That means we can be confident there will be
nothing different or special happening inside that gap.

When trying to fill any gap in our existing knowledge, that piece of
advance information - that the same fundamentals will apply - is a
tremendous help. Or it should be... the trouble starts when someone
tries to ignore that fact, or worse still, tries to fight it.

It is also important to note that there are already several other ways
of thinking about loaded antennas that DO fit perfectly into the puzzle.
There are many alternative ways to think about any particular piece, and
as long as they fit with reality all around them, they are
interchangeable.

Cecil wants to try a method based on forward, reflected and standing
waves, and that's just fine. As i said, I'm sure it can be done. The
existing knowledge that such a theory must fit includes: what travelling
and standing waves are; what electric current is; what inductance does;
how real-life coils are different; and how things change when circuits
become physically large enough to make electromagnetic coupling
important (so we begin to call them antennas).

But Cecil's new piece for the puzzle uses new and special definitions
and properties for electric current, inductance, and travelling and
standing waves - they are not the same as in all the surrounding pieces.
To me, that is absolute proof that his new piece doesn't fit. He has
bent the rules to make it resemble the correct shape, but the colors
don't match.

Exactly why it doesn't fit remains a matter for debate. But I am
fundamentally sure of the *fact* that it doesn't.


(Will be away from the screen now until about Tuesday.)



--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek