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From: Dan Maguire <bethdan at pacbell.net>
To: qrp-l at Lehigh.EDU
Subject: [124939] Running Antenna Modeling Programs on AutoPilot

MultiNEC is a new Excel application that can make multiple simulation runs
of an antenna model while automatically changing one or more aspects of the
model between runs.  You can change the model in a variety of ways, choose
from a variety of calculating engines, and view the results in a variety of
formats.

The model can be automatically changed between runs in several ways.  The
simplest is to just use a different frequency for each test case, equivalent
to a normal frequency sweep.  You can also specify that one or more wires in
the model are to be rotated, moved, scaled, or have a different segmentation
level between runs.  You can change the parameters of sources, loads, and
transmission lines, such as the position of a source along a wire or the
resistance value for a load.  Finally, MultiNEC contains a complete modeling
by equation facility.  You can create the model using Excel spreadsheets and
then instruct the program to change the geometry or other aspects of the
model in any way that can be specified using Excel formulas.  All these
changes may be made automatically without the need for any manual
intervention between simulation runs.

You have several choices as to the calculating engine that will be used for
the simulations.  If you have either standard EZNEC or EZNEC Pro you may use
the NEC-2 and NEC-4 engines that are included in those packages.  If you
have NEC-Win Plus+, NEC-Win Pro, or GNEC you may use the engines from those
as well.  You may also use the public domain NEC-2 engine that is bundled
with MultiNEC.

The simulation results are available in tabular format or in several
different plot formats, including a far field polar plot, three standard
rectangular plots, and a custom rectangular plot on which you may choose any
desired X and Y axes.  The polar plot can be used to play back the radiation
patterns for the test cases as an animation.  The custom plot can show a
regression analysis curve and matching equation for the plotted points.

In addition to the "multi-run" capability, MultiNEC is also "multi-lingual."
You can import existing antenna models that are in EZNEC binary format
(.ez), NEC "deck" format (typically .nec or .inp), or MMANA format (.maa).
Once the model has been imported you may run it on any of the available
engines.  For example, you can import an EZNEC binary format model and run
it using public domain NEC-2.  Or you could import a nec file and then use
EZNEC as the calculating engine.  Since MultiNEC can produce output files in
either .ez or .nec format, you can use the program as a translator between
file types.

More details and a free download file may be found at www.qsl.net/ac6la.
Requires Excel 97 or later.

73,
Dan
AC6LA

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Date: Sat, 28 Sep 2002 19:24:11 -0400
From: Michael Babineau <michael.babineau at sympatico.ca>
To: steve at eclipsecat.com
Cc: qrp-l at lehigh.edu
Subject: [136446] re:beginner's Antenna modeling software

Steve :

I would recommend EZNEC by W7EL. You can download a fully functional
demo version (limited by the number of segments you can use in the 
model) and
model some simple antennas with it for free.

Try http://www.eznec.com/index.shtml

LB Cebik wrote a very good 3 or 4 part series in QST about a year or so 
ago on
antenna modelling that was a very good introduction.

Michael VE3WMB

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