On Sat, 19 Aug 2006 00:52:40 GMT, "Frank's"
wrote:

....
Hope you managed to follow my rambling description. To say the
least it requires a lot of tedious data manipulation with Excel.
If you are interested I can e-mail my spread sheets, NEC input
and output files, etc.

Frank,

You might want to consider a scripting environment to build, run, and
summarise NEC runs.

Windows lacks a good scripting language for this type of application.
Fortunately there are others available, and at no charge. Two that I
have used are PERL and Python.

I prefer PERL mainly for historical reasons and the huge base of
packages to extend the PERL base, though Python is probably a better
designed language, and less likely to change radically (as PERL looks
likely to do with V6). Importantly, both natively support complex
number type. For instance, you can write in PERL:

#calculate Zo and gamma
my $a=$R+i*2*PI*$this-{f}*$L;
my $b=$G+i*2*PI*$this-{f}*$C;
$this-{zo}=($a/$b)**0.5;
$this-{gamma}=($a*$b)**0.5;

PERL is excellent for reading megabytes of NEC output and extracting
key figures for summarisation.

An example, I recently wanted to explore the relationship between
predicted beamwidth (in E and H planes separately) and gain for DL6WU
long boom Yagis. I built and ran literally hundreds of models with
pattern reporting at 0.1deg intervals, producing over 50MB of output.
Models were automatically generated from a PERL port of the DL6WU
design algorithms, and NEC runs of the generated models were
automated. Half power point was found by linear interpolation between
0.1deg points around the half power points. If I did that by hand, I
would be working for months, whereas a half hour of scripting produced
a solution that was more accurate and reusable.

Is there a place for Excel? Certainly, I usually create tab delimited
summary files with PERL scripts and drop them on Excel to the final
ad-hoc analysis and presentation. DPLOT is also a pretty neat tool for
graphical analysis and presentation. For example, the regression
analysis of the data from the study above
http://www.vk1od.net/dl6wu/new_pa2.gif was calculated and displayed
using DPLOT.

Worth the investment in learning PERL (or the like)!

http://www.perl.org/ (You need the Activestate PERL for Windows.)

http://www.python.org/

http://www.dlot.com/


Owen
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