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RE: Re: Fasthenry program does much more than I originally thought

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rob-at-pythonemproject-dot-com>

Yes, you are absolutely right.  The EM simulators are very much "Garbage-in
Garbage-Out"  I have a copy of WIPL-D here (which stands for
Wire-Plate-Dielectric).  Its one of the best antenna simulators around.
Yet, I've only been able to model wire antennas with it, because the
construction of surfaces and bodies of revolution requires an intimate
knowledge of how an FEM-MOM hybrid simulator works.  And I'm not there yet.
 I finally was able to simulate a 50 ohm trace on a pc board with it,
though :) :)


>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Sent: Fri, 03 May 2002 10:33:59
>Original poster: "Jim Lux by way of Terry Fritz
><twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>
>> Original poster: "rob by way of Terry Fritz
>> I had some free time at work today and already
>have a working core of a
>> Python language preprocessor for fasthenry.	I'm
>calling it "fastTesla"
>> :)
>> I was amused at some  assertions I saw that it
>wasn't possible to
>> accurately model inductors and capacitors.  The
>programs that do this
>> are full-wave EM type simulators, and
>unfortunately they cost about
>> $10000 per node license (e.g. Zeland Software and
>Ansofts HFSS).  If it
>> wasn't possible to accurately model inductors and
>capacitors, my company
>> would have been in Chapter 11 long ago.  We
>manufacture MMIC's, and our
>> biggest problem is modeling the nonlinear
>capacitances of the active
>> devices that are attached to the inductors. 
>Passive devices are no
>> problem.
>Just like when modeling antennas, I suspect the
>real problem for TCs will be
>describing the model sufficiently well, not the
>fidelity of the simulation.
>It's all those construction tolerance things...
>nonuniform windings, etc.
>That said, some basic approximations and shortcuts
>(assuming constant turns
>per inch, etc.) would get us started, and then, you
>could do some Monte
>Carlo'ish sensitivity analysis. Practically
>speaking, it's probably not
>worth it... Construction tolerances are probably in
>the few percent area,
>and the existing fairly straightforward models are
>more accurate than that.
>Heck, a simplistic Wheeler and Medcalf
>approximation is almost that good,
>except for the topload/secondary Cself problem...
>I think the real value of high performance
>simulation will come in
>accurately modeling the spark growth, top load,
>secondary coil interaction.
>The primary/secondary interaction is pretty
>straightforward.. The other area
>of some interest would be integrating a suitable
>model of the primary spark
>gap in a timedomain simulation..
>Correct me if I'm wrong, but the great work by
>Paul, etc., is basically
>quasistatic steadystate for the fields and fluxes.