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HB9ABX > TECHNI 12.06.20 16:25l 88 Lines 3793 Bytes #999 (999) @ WW
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Subj: Antenna Simulation ...
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Sent: 200612/1414z @:DB0FHN.#BAY.DEU.EU [JN59NK Nuernberg] obcm1.07b12 LT:999
From: HB9ABX @ DB0FHN.#BAY.DEU.EU (Felix)
To: TECHNIK @ WW
Reply-To: HB9ABX @ HB9EAS.CHE.EU
X-Info: Sent with login password
My opinion regarding computer simulation programs
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Computer Simulation Programs (CSPs) like NEC and its family (EZNEC, NEC2, MMANA
etc.) may have a very high value in optimizing antenna systems of well known
structures.
But in order to search and evaluate new types of antennas, it seems to me
questionable to use such programs.
The programs are based on formulas, which were developed to describe the
behaving of antennas of well known structures.
Note especially this >>> antenna simulation with NEC
See here: http://hb9abx.no-ip.biz/ant-mar19-07e.htm
All formulas have a validity range, and using them outside this range may lead
to completely wrong results.
Unfortunately, this is mostly disregarded in educating EEs, which is in my
opinion one of the main reasons, why large engineering companies have lost
their reputation, their customers, and finally had to fire thousands and
tenthousands of employees ...
(e.g. BBC Brown Bovery Company and similar companies).
It is not done by teaching formulas and the mathematical tools with the ability
to write long mathematical derivations.
Most important is, to understand mentally all used formulas and to be creative.
That is the basis of successful engineering.
All used formulas describe an idealized behaving of structures, disregarding
small effects which remain unnoticed under standard conditions.
Most people are very impressed by the beautiful diagrams produced by these
programs and think, that the computer is modeling the full reality.
The result is good, if the evaluated structure corresponds to the program, and
if the environment is specified correctly.
The output provided by these programs may represent very closely
the reality, but it also may be completely wrong.
When searching new concepts and evaluating new ideas, the only correct way is
by doing experiments in real world.
Measuring the results may lead to new formulas which describe this behaving,
and using these new formulas in a CSP helps then to further optimize the
construction.
That's the way new constructions and concepts are found.
My personal experience in high tech engineering duringthe last 3 decades
demonstrated very clearly, that large companies lost millions and millions of
dollars due to misuse of very good formulas and programs - just by disregarding
the validity range of these very important engineering tools, or caused by one
dimensional thinking.
Just a simple example:
In the 1960s we developed the first phone line modems.
They operated at 200, 300, and 600 bps.
We were told by our professors, that the maximum speed that ever could be
reached would be 3800 bps, as the phone line cuts frequencies above abt. 3800
Hz.
You know what bps rate today is possible over the phone line ...
They simply could not imagine, that you may combine phase-, amplitude-, and
frequency modulation simultaneously in new techniques!
A further example:
Caused by misunderstanding of the applied formulas, a loss of over 40 million
dollars resulted in the development of a high tech military product, the group
was lead by doctors in Physics and Mathematics ...
Even in large companies such tremendeous errors may not occur frequently, as
this will lead to that what happened ...
Similar things happen today in new antenna projects.
Never say "this is physically not possible", because
tomorrow one might show you, that it IS POSSIBLE.
The successful way goes through understanding and real world experimenting !
Wishing you a good success in your next project
best 73, Felix. HB9ABX ( felix-abx at gmx.ch )
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