Re: 1/4 wave theory/cite the variance?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Dave Thomson wrote:

> Perhaps your modern view and Tesla's view are both right?  The
> arguments being brought up in favor of an adjustment to quarter
> wave are based on tightly wound coils with self-capacitance and
> tightly coupled inductance between the wires.

I understand what you're saying.

Two things.  First, there are no 'arguments' as such, this issue
is not a theoretical point to be debated - rather, it is an
unequivocal experimental observation.  Our opinions, therefore,
don't matter.

Secondly, the contribution of the capacitance between neighbouring
turns to the total effective self-capacitance of the coil is very
small - of order 1%.  

For typical TCs operated near to the earth, the bulk (circa 80%)
of the effective capacitance comes from the capacitance between the
turns of the coil and its surroundings, mainly the earth, but also
walls etc.  Most of the rest of the capacitance comes from the
capacitance between turns which are widely separated along the coil.

There are two good reasons for the kind of low spacing ratios that
we often see in these early coils.  One: to achieve sufficient
breakdown potential between neighbouring turns, and two: to obtain
a higher Q factor - closely packed turns suffer a particularly
high proximity loss.  BTW, this is especially true of spiral coils
when close wound from flat tape or strap.

> you will see that all of Tesla's coils are space wound, thus
> eliminating the effects you're mentioning.

Your assumption that we are foolish enough not to thoroughly check
these things is disappointing, to say the least, and it is becoming
clear that you have taken little time out to study the basics of Tesla
coiling (or indeed physics in general) before launching into
'research'.
--
Paul Nicholson
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