
MultiNEC Sample Models:  These files are all in MultiNEC format (.weq) so you 
access them using the 'Open Model File' button on the Wires sheet or using the 
corresponding selection from the MultiNEC custom menu.  


Example1.weq et. al.  (6 models)
20M5ELYA.weq
  These models may be used with the MultiNEC examples in lieu of entering all 
the necessary information manually on the various MultiNEC sheets.   


SquareQuadArray.weq
  Two square loops.  This is the model used for illustration purposes on the web 
pages.


DiamondQuadArray.weq
  Three elements in a diamond configuration.


RightAngleDelta.weq
  A single delta loop.  The geometry of this model is straightforward.  I 
included it to show a few other things you can do with formulas.  The Z height 
offset is for the base leg, but you might be limited on the height of the apex 
because of the available support.  Cell E16 on the Equations sheet shows the 
apex height in feet; you might want to adjust control variable "B" to achieve a 
specific apex height.

This model also shows formulas for the segmentation using the variable "I", 
created via the AutoSeg button.  Because the wires are not all equal length you 
can't just pick a number for the segment count and have the segment lengths be 
uniform.  Using a formula for segmentation results in roughly equal segment 
lengths.  Since you might want to put the source on the bottom leg an "ODD" 
variation is used for the formula for that leg; for the other legs it doesn't 
matter if the segment count comes up as odd or even.  Use of a variable to 
control the formula lets you easily increase the segmentation level for 
convergence testing.

Row 12 on the Wires sheet shows that you can also use formulas in comment lines.  
When side-fed, the loop should be fed 1/4 wl down from the apex.  The formula in 
the comment reminds you where the ideal feed point would be, which changes 
slightly as the size of the loop is adjusted for resonance.  Of course the 
number only changes by a small amount as the loop size is changed, and you 
probably won't be able to hit that exact point unless you use a very large 
number of segments, but the idea is that you can use formulas in places other 
than wire coordinates.


OctagonLoop.weq
  A simple "almost-round" loop.  Included only to show the formulas that are 
used in the construction of an octagon.  You might use this as the basis for a 
more complicated model such as a multi-element array.


OctagonHelix.weq
  The octagon loop from above, duplicated 10 times with the X coordinates 
incremented by an amount that is determined by the desired pitch of the coil.  
You might use just the helix as the basis for an antenna.  (See the LB Cebik 
example using a hexagon helix, found on his "Antenna Modeling" pages.)  I 
decided to add 3 more wires so I could attempt to model an actual closed coil.  
The result for the reactance of the source is fairly close (within 10% or so) to 
what you get using the equations for a lumped coil, as long as the lead length 
is included.  I can't say why you'd ever want to use NEC to simulate a real 
coil, but I had a good time playing with this one. 


PentaBandDiamond.weq
  This is a design taken directly from the ARRL Antenna Book, 19th edition, page 
12-8, "A Two-Element, 8-Foot Boom PentaBand Quad."  I included it as a sample 
for a couple of reasons:  1) To show that you don't have to create fancy 
formulas for your variables.  For this multi-band antenna all variables are 
entered and used directly in feet and there are no formulas at all on the 
Equations sheet.  2) To show how you can really use Excel's 'Copy/Paste' and 
'Edit/Replace' functions to your advantage.  The only formula I typed completely 
was "=A/4 / SQRT(2)" for one of the Y coordinates of the first loop.  Putting a 
negative sign in front of this covered another Y coordinate.  Adding "+ O" 
[letter oh, not zero] after it covered the Z coordinates.  Once I got all the 
End 1's done for the first loop I copied these formulas to the appropriate End 2 
cells, as described in the web page example.  Then I viewed just that one loop 
so I could make sure I had everything correct.  From then on it was just a 
matter of copying groups of cells to other locations and doing various 'Replace' 
operations to change the name of a variable.  The whole antenna was defined in 
less than ten minutes.  Since I did not use any intermediate formulas, the 
expression "SQRT(2)" gets evaluated 320 times (40 wires X 2 ends per wire X 4 
places for each end).  But this is just the kind of thing that modern computers 
do very fast, so the computer time wasted is inconsequential.  Note that column 
"J" of the Wires sheet may be used for annotation if desired, such as to show 
reminders of which wire gets the source for various bands.


Yagi20Heavy.weq  et. al. (6 variations)
  Recent editions of the ARRL Antenna Book contain some 68 optimized Yagi 
designs covering the bands from 40 to 10 meters.  These MultiNEC sample files 
are templates for the tubing taper schedules of the ARRL Yagis that cover 20 
meters, 15 meters, and 10 meters, with the Medium duty and Heavy duty versions 
of each.  These templates make it easy to create any of the 40 optimized designs 
that cover these bands.  There are files for each of the six variations, so you 
can change to a different design just by opening the appropriate file and then 
changing the spacing and tip length variables to the values as shown in Chapter 
11 of the Antenna Book.  All dimensions are in inches.  These models must be run 
using either EZNEC or with the StepRad module and NEC-2.  Running with just 
plain NEC-2 will result in inaccurate calculations.  You can also run these
models using the Antenna Model engine, since Antenna Model uses a modified
MININEC type engine that can handle stepped diameter wires with no problems.
