On Tue, 10 Oct 2006 18:36:23 -0700, Richard Clark
wrote:

On Wed, 11 Oct 2006 00:33:58 GMT, Owen Duffy wrote:

On Tue, 10 Oct 2006 17:17:33 -0700, Richard Clark
wrote:

On Tue, 10 Oct 2006 23:29:22 GMT, Owen Duffy wrote:

I would appreciate comments

Hi Owen,

Maybe use a log-log scale?

It is if you think about it, -20log(Vout/Vin) vs log(Freq).

Hi Owen,

I suppose so, however, when I see a sigmoidal curve, it begs a
different representation which, to me, reveals an underlying concept
(whatever that might be). Even with the redundancy of log
representation of a log value, its straight line representation may
worth consideration. I don't know why at this pass. This is just a
preference I would consider.

I know we like to see straight lines in things, leads to simple
explanations.

I think a piecewise explanation of what happens here is:
- below the second knee, current is uniform and:
- below the first knee, loop inductive reactance is small, and
induced voltage is dominated by the changing freuency;
- above the first knee, induced voltage still varies with frequency,
but the loop inductive reactance is compensating that to a fair extent
and current (or loaded terminal voltage) is almost constant with
change in frequency;
-above the second knee, current is not uniform, reactance changes more
rapidly with change in frequency as resonance is approached, induced
voltage increases with increase in frequency.


I am really interested in modelling accuracy issues like
segment length,

Generally self-driven by the results of successive modeling of
increased segmentation approaching an asymptotic level. The implicit
question would be: "Does the addition computational load warrant the
increased count?"

The computation load isn't a big issue in these case, and I have
changed the segmentation with minutest change in results around the
current segmentation strategy.


right angle corners,

Area dominates such considerations, practicality is also significant,
results generally varies by little. As Reggie would offer, it is a
trade-off in the amount of wire, and spacing that would tend to
increase loss, and give rise to self resonance. He offered very good
advice on the size of coils, and this may have occurred before you
joined the group. I'm sure a review of his web page would reveal an
"unzipped" executable, but may lack the discussion he offered here.

Certainly, it can be solved from first principles at lower frequencies
where current is uniform, and as you say, area and self inductance are
the critical quantities. It is at the right hand end where current is
non-uniform that the NEC model becomes most relevant, and where I
depend on its accuracy... if I got things right!


load placement etc.

An issue of balance (physical placement mimicking literal field
balance).

Thanks Richard,

Owen
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