On 5 Mar, 11:00, Jim Lux wrote:
art wrote:
On 5 Mar, 09:59, Roy Lewallen wrote:
snip

Anyone who claims to have discovered principles which are beyond those
incorporated in current programs has a heavy burden of proof to bear.

The principle that I have discovered is not in a book but if a program
is made up of proven facts of the masters proves one thing that is not
ably checked by other programs based on the same facts then humasn
intervention
is the problem and not the principles of the masters. If one deduces
an area that the masters have neglected to expand and a computor

The very first hurdle to overcome in order to gain any semblance of
credibility is comparison of carefully and professionally measured data
with results from a carefully and professionally created model. If the
differences truly are unexplainable by known deficiencies, then further
investigation is surely warranted. Vague claims, speculations, and
arm-waving with a total lack of any quantitative data are far short of
what is needed to gain the attention of anyone who has seen, over and
over, the successful results these programs routinely provide.

Roy Lewallen, W7EL

Computor programs made by professionals do not agree with each other
so there is a problem.

I would suggest that the various codes used by professionals DO agree,
within their stated uncertainty limits or the constraints of the model.

A simple mutual coupling approximation based on series expansion of the
exponential integral for idealized dipoles will be very close to that
derived from, say, a method of moments code like NEC2, but they will be
different, because the underlying model is subtly different. However, a
skilled user of such codes is (or should be) aware of the limitations.

Likewise, you can model a vertical monopole over ground with a simple
model (like assuming the ground is infinitely conducting and the
monopole is infinitely thin). Or you can model it as a finite thickness
monopole and a finite conductivity dielectric ground with uniform
properties. Or, you can model it with the rivet heads holding the
aluminum together, the dielectric guy wires, and the actual EM
properties of the soil that have been determined on a 10cm grid for the
surrounding km.

The answers will all be different in the details, but simultaneously the
answers will be the same within the limits of the approximations used.

The devil is in the details of those limits, eh?
Jim- Hide quoted text -

- Show quoted text -

Well you can run around in circles if you think it denotes progress.
If you are really interested in the subject put the same 3 element
antenna
in super nec and 4 nec2 using all dimensions as variable and guess
before hand what result one will give you compared to what the other
one gives you
and ask yourself why with respect to the answer given.
Ofcourse you can say thats not my job and then shoot the messenger.
Do what you think is right. Im doing what I know is right
Regards
Art