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MultiNEC Version 1.4
October 25, 2002

See the end of this file for change history.  


Installation:

Stop!  If you intend to use MultiNEC with EZNEC please check the version number 
of your copy of EZNEC using menu selections Help, About EZNEC.  If lower than 
version 3.0.38 you must download and install the latest maintenance update file
from www.eznec.com before continuing.  If you intend to use the '4nec2' program
you must have version 4.2 or later.  If you intend to use the Antenna Model
program you must have version 2.0.0.555 or later.

Unzip the MultiNEC.zip file to a folder named C:\MultiNEC or other name of your 
choice.  Be sure to include sub-folders when unzipping by selecting the "Use 
folder names" option of WinZip Extract.  The MultiNEC package contains the 
following files and folders:


ReadMe.txt
  This file.


MultiNEC.xls
  An Excel workbook containing various sheets along with Visual Basic code.  The 
presence of the Visual Basic macros will cause Excel to show a 'Virus Warning' 
alert when this workbook is opened unless you have disabled that Excel option.  
You may scan the workbook file using any virus checking program (e.g. Norton) to 
assure yourself that it contains no viruses.  Important:  If you are running 
Excel 2000 at the High security level you will not be given the option to 
enable macros and MultiNEC will not function at all.  Under Tools, Macro, 
Security, set the security level to Medium.  Then at least you will have the 
option to enable Visual Basic macros each time you open a workbook.


GoNec.bat
Infile.dat
$Multi$.nec
Nec2d.exe
Nec2d960.exe
Somnec2d.exe
F77L3.eer
  These files are all associated with using the public domain version of NEC-2 
as the calculating engine.  They must all reside in the same folder, C:\MultiNEC 
by default, with the exception of $Multi$.nec which is recreated as needed.  The 
folder name may be changed using the 'Setup,Options' button on the Calculate 
sheet of the MultiNEC workbook.
  The $Multi$.nec file is the input file to the NEC program.  The same file name 
is used, but with different contents, each time NEC is invoked.  You may rename 
this file and/or move it to another folder if at any time you want a permanent 
copy.  You may also use the 'Save Model As' button on the Wires sheet.
  The maximum number of segments in an antenna model that can be handled with 
the above files is 960.  See the GoNec.bat file for instructions on changing 
this limit, accomplished by downloading additional Nec2d files provided through 
the courtesy of Jos Bergervoet.


\Grounds
  Must be a sub-folder under the above.  Contains Sommerfeld ground files.  
These files are reused if possible to save execution time when using the public 
domain version of NEC-2 as the calculating engine.  New files will be created in 
this folder as you run different frequencies or different ground characteristics 
with Sommerfeld ground.


\Samples
  Contains several MultiNEC example files of type *.weq.  Need not be a sub-
folder, may be moved or renamed at your discretion.  Described in more detail 
below.


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Setup and Testing: 

  1) If you intend to use MultiNEC with EZNEC please read this item, otherwise 
you may skip to item #2.
  Start EZNEC in the usual manner.  Click on 'Help' then 'About EZNEC' to check
the program revision level.  You must have version 3.0.38 or higher in order to
use EZNEC with MultiNEC.  Free updates are available at www.eznec.com.
  In order to be used by MultiNEC, the main EZNEC window should be left open in
a stand-by state.  You may close the various sub-windows of EZNEC such as the 
View window but do not close the main Control Center window.  If the main EZNEC
window -is- closed MultiNEC will usually be able to start a new instance of
EZNEC but this will result in a delay in processing.  The EZNEC window may be
minimized if you like although this is not necessary.

  2) If you intend to use MultiNEC with any of the supported Nittany Scientific 
modules please read this item, otherwise you may skip to item #3.
  MultiNEC can interface with the StepRad Leeson correction module that is part 
of NEC-Win Plus+, with the enhanced NEC-2 engine that is part of both NEC-Win 
Plus+ and NEC-Win Pro, with the enhanced NEC-4 engine that is part of GNEC, and 
with the NecVu viewer and geometry checker module that is included with all of 
these Nittany Scientific products.  Depending on the module to be used and the 
product that is installed you may need to request a revision level upgrade via 
email to tech-support@nittany-scientific.com.  MultiNEC will show a warning 
message if the level of any module is earlier than that required for the 
interface. 
  There is no specific interface to the NEC-Win Synth product.  You may build 
structures using Synth, save the model in NEC Input File (.nec) format, and 
import the nec file into MultiNEC in the usual manner.  Note that it will be 
necessary to define a source for the model before it can be calculated.  You may 
do this using the Src-Ld-TL sheet of MultiNEC.

  3) If you intend to use MultiNEC with the Antenna Model (A.M.) program by Teri
Software please read this item, otherwise you may skip to item #4.
  Start A.M. in the usual manner.  Click on 'Help' then 'About ...' to check the
program revision level.  You must have version 2.0.0.555 or higher in order to
use A.M. with MultiNEC.  You can use the 'Check for Updates' utility in the A.M.
program group to get updates over the Internet.
  When you load an existing A.M. format (*.def) model into MultiNEC all symbol 
names will be converted to an equivalent MultiNEC A-Z variable name.  You can
then use MultiNEC to run a single test case with the A.M. engine, to run a 
frequency sweep set of test cases, or to run a set of test cases with one or
more variables (symbols) being automatically changed between runs.  You can also
run the model using any available EZNEC or NEC engine.  Keep in mind that when 
using A.M. any wires that are to contain centered sources or loads must have an
even number of segments, but when using EZNEC or NEC any such wires must have an
odd number of segments.  MultiNEC will warn you of any such even/odd problems.
You may continue or you may choose to stop and re-segment one or more wires.
  When you load a model that was originally intended to be run with EZNEC or 
NEC, or when you create a model from scratch in MultiNEC, you must keep in mind
some important items in addition to the even/odd segmentation.  First, A.M. does
not have the Sommerfeld type ground.  Any models with horizontal wires (or wires
with a horizontal component, like sloped wires) that are lower than about 0.2
wavelengths above ground will show inaccurate impedance and gain results.  This
may or may not matter to you as the relative radiation pattern shape will stay
the same even if the absolute dBi figures are imprecise.
  Second, some antennas may require a higher level of segmentation than what you
may be used to with NEC or EZNEC.  In particular, the wires in square and delta
loops should have 60 to 70 segments per wavelength instead of the more normal 
20.  You can use the MultiNEC AutoSeg function to set the segmentation level.
For more information see the "Segmentation: Automatic or Manual?" section in the
A.M. Help.  For information on using a variable name with the MultiNEC AutoSeg
function and then doing an automatic convergence study see Example 1,
"Convergence with Variable Segment Level," in the MultiNEC documentation.
  Also, remember that A.M. positions all sources and loads based on "pulses"
and not on segment centers as is done with NEC and EZNEC.  If you want to place
a source or load at the end of a wire (0% or 100% from End 1 in MultiNEC terms)
you must be careful to insure that a "pulse" exists at that location.  For
example, to model a ground plane antenna with four radials and one vertical
wire, with the source at the bottom of the vertical wire, the vertical wire must
not be defined as the first wire.  For more information see the "Ground Plane"
section in the A.M. Help.  Another good explanation of this situation may be 
found in "MININEC: The Other Edge of the Sword" by Roy Lewallen, QST, February 
1991.  MultiNEC will generally be able to automatically convert between "end of
wire" sources for A.M. use and "Split" sources for use with either EZNEC or NEC
engines, but this only applies to a two-wire junction.  In cases where a source
(or load) is to be placed at a junction of more than two wires you should
always double check the placement.
  Finally, keep in mind that A.M. (or any MININEC-based program) will only join
wires together at their ends.  With NEC it is permissible, although usually not
recommended, to intersect the end of one wire at a segment boundary on another
wire.  Thus you can make a "T" intersection with only two wires.  With A.M.,
a "T" intersection requires three wires such that they all join at an end.

  4) If you intend to use MultiNEC with 4nec2 please read this item, otherwise 
you may skip to item #5.
  Start 4nec2 in the usual manner.  Click on 'Help' then 'About 4nec2' to check
the program revision level.  You must have version 4.2 or higher in order to use
4nec2 with MultiNEC.  The latest revision of this very nice freeware program may
be obtained from www.qsl.net/wb6tpu/swindex.html.
  Note that MultiNEC does not interface directly with any of the NEC engines
that may be included with the 4nec2 package.  MultiNEC uses only the Geometry
View and 3D Plot functions of 4nec2; all required NEC files are constructed and
manipulated external to the 4nec2 program itself.  In particular you must make
sure that a NEC-2 type engine is available for use by MultiNEC, even though the
4nec2 package may have installed its own engine(s).  See item #5 below.

  5) If you intend to use the public domain version of NEC-2 that is distributed 
with MultiNEC please read this item, otherwise you may skip to item #6.
  Using Windows Explorer, locate and expand the C:\MultiNEC (or as-named) 
folder.  Test the interface to NEC-2 by double-clicking on the GoNec.bat file.  
If a window with the words "Requires MS-DOS mode" appears click No.  (It is not 
an error if this window appears.)  After a few seconds two additional files 
should appear in the folder, Nec2d.log and $Multi$.out.  If the "out" file does 
not appear check the "log" file for possible problems.  Both files may be viewed 
using Notepad. 
  Windows XP users:  This version of NEC-2 will not work under the Windows XP 
operating system.  Replacement NEC-2 modules are available.  If you want to use 
the public domain NEC-2 calculating engine under XP please contact me for more 
information.  The EZNEC and Nittany Scientific calculating engines are not 
affected by this problem. 

  6) It may be possible to modify the GoNec.bat file to invoke a DOS version of 
NEC-4 if one is available.  Please contact me directly for more details.  NEC-4 
is subject to licensing and export restrictions.

  7) Start Excel with a new (blank) workbook.  If you are running Excel 2000 
click on Tools, Macro, Security.  Choose either Medium or Low security level.  
If you have the High option chosen the MultiNEC workbook will not function at 
all.  Under Excel 97 there is no equivalent to the High level so this is not a 
problem.
  Now open the MultiNEC workbook.  If your screen size is at 800x600 resolution 
you will probably want to maximize the Excel window in order to avoid having to 
do a lot of up-down scrolling to see the various charts.  On the other hand, if 
you are using a higher resolution you might want to reduce the Excel window so 
you can see other parts of your desktop.  Try resizing the window such that the 
three charts on the Rect Plots sheet are all visible.
  In either case you may wish to turn off the various Excel toolbars to maximize 
the amount of usable window space available.  (I always run Excel with all 
toolbars turned off and only enable those I need as necessary.)  Click on View, 
Toolbars, then uncheck everything.

  8) Switch to the Calculate sheet of MultiNEC, click on the 'Setup and Options' 
button, then change the various settings for available programs and folder names 
to match your environment.

  9) The MultiNEC workbook comes preloaded with the Square Quad Array example 
that is described on the web site.  Try the various functions and interfaces to 
available modules to make sure everything is working as it should.  Don't 
hesitate to experiment.  You can always use the Excel menu bar selection File-
Close (without Save) to close the MultiNEC workbook and then File-Open to start 
fresh

 10) Although MultiNEC has the "look and feel" of a normal application, keep in 
mind that you are actually running a specialized Excel workbook.  As such, most 
menu selections that appear along the top of the application window are used to 
perform "Excel type" functions and not "MultiNEC type" functions.  For example, 
to load a new antenna model into the workbook you click the 'Open Model File' 
button on the Wires sheet.  You do not use the File-Open menu selection unless 
you actually want to open a new Excel workbook, such as one you may have created 
to track the family budget.  Similarly, to save an antenna model you click the 
'Save Model As' button.  You do not use the menu selections File-Save or File-
Save As, both of which result in saving the actual workbook.  When you close 
Excel in the normal manner the MultiNEC workbook will be saved in its current 
state, including any changes you may have made such as loading a new model and 
performing calculations for that model.
  The exception to this rule is the use of the special "MultiNEC" choice that 
appears as the last item on the menu bar.  This custom menu contains selections 
that duplicate some commonly used MultiNEC worksheet buttons.  Selecting one of 
these custom menu items is equivalent to clicking the corresponding button, 
without the need to tab to a particular sheet.

 11) There may be times when you want to remove a row of entries from a 
worksheet, such as a wire specification, a source definition, or a test case 
entry.  To do this you can drag through all the appropriate cells, right-click, 
then select Clear Contents from the shortcut menu.  You can also drag through 
the cells and then press the keyboard Delete key.  Under Excel, the Delete key 
is equivalent to Clear Contents.  On the other hand, the Excel Delete function 
(not to be confused with the Delete key) should not be used in cases like this, 
since both the Delete and Insert functions actually remove or add cells to the 
worksheet, shifting other cells up, down, left, or right as necessary.  With 
complicated workbooks such as MultiNEC this usually produces undesirable effects 
on pointers and references in the underlying logic.  To avoid this problem, the 
Excel Delete and Insert functions are not available for the MultiNEC workbook.
  You should also avoid clearing an entire worksheet-wide row of cells, usually 
done by clicking on the row header number on the extreme left side of a sheet to 
select the entire row and then selecting Clear Contents.  Clearing a row in this 
manner will clear -all- cells in the selected row, including cells on the far 
right side of the sheet that may be in use but not visible.  MultiNEC contains 
special logic to prevent you from selecting worksheet-wide rows for just this 
reason.
  Since the Delete and Insert functions are not available, how can you add a new 
entry in the middle of a set of existing entries?  The easiest way is to select 
all entries below the desired row, drag the selection down on the sheet, then 
enter the new information in the blank cells.  In a like manner, you can drag a 
selected set of cells up on a sheet in order to replace any blank cells above 
the selection.  You can also use the Excel Cut and Paste functions to perform 
these actions, but it is usually easier to just drag a set of cell entries up or 
down on a sheet.

 12) The MultiNEC workbook should load in less than 15 seconds on all but the
slowest computers.  If you have to wait longer than that it may be because an
excessively large number of files have accumulated in the Windows temp folder.
Try closing all applications and making sure that there are no print jobs in the
queue.  Then look in the C:\Windows\Temp folder (or in the C:\Documents and
Settings\<user name>\Local Settings\Temp folder under Windows XP).  You can
probably safely delete any *.tmp and *.emf files that are found.  If you are not
sure if any of these files are still needed just move them to another folder
(perhaps ...\Temp1) instead of deleting them.  Having fewer files in the Temp 
folder and/or deleting any corrupted *.emf files will improve the Excel load 
times.

 13) Some users have reported erratic behavior such as extremely slow response 
times or the failure of certain windows to close automatically.  This is related 
to having the Norton AntiVirus Auto-Protect feature enabled.  If MultiNEC does 
not seem to be working properly try right-clicking on the Norton icon in the 
Windows taskbar and selecting 'Disable Auto-Protect' mode.

 14) International users:  You should enter numbers using your customary 
character for the decimal separator, either a comma or period depending on your 
language as set via the Windows Control Panel Regional Settings.  All MultiNEC 
results are displayed in the appropriate format.  The switch between commas and 
periods that is necessary to interface with the NEC engines is done without any 
user intervention.  

 15) Finally, please take some time to read the extensive documentation that is 
found under the MultiNEC link at www.qsl.net/ac6la, including the detailed 'Tips 
and Tricks' and 'Examples' sections.  The same information is also found in the
MultiNEC User Manual, reformatted as a *.pdf document for more convenient use.


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MultiNEC Sample Files:  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.


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MultiNEC Change History:

Version 1.0 - April 1, 2002
  *  Initial release.

Version 1.1 - April 17, 2002
  *  Interface to the Nittany Scientific calculating engines and viewer.
  *  Interface to the EZNEC Pro (EZNEC/4 and EZNEC-M) programs.

Version 1.2 - July 24, 2002
  *  Add support for entry and display of non-English language number formats
     that use a comma as the decimal separator.
  *  Import *.ant type files as are used by the K6STI AO and NEC/Wires programs.
  *  Handle "SY" (Symbol) cards that may be placed in "pseudo-NEC" files by the
     4nec2 program.
  *  Allow for a max of 30 sources, 30 loads, and 30 transmission lines.
  *  Show EZNEC Antenna Notes text, if any, when importing EZNEC type files.
  *  Import non-English MMANA (*.maa) files.  Show comment text, if any.
  *  Add custom "MultiNEC" menu with commonly used functions.  Includes an
     "About MultiNEC" choice that shows the version number and date.

Version 1.2.1 - August 1, 2002
  *  Perform additional error handling when importing AO (*.ant) type files.
  *  Remove access to the Excel Insert and Delete functions.  For more on this
     topic see item #11 in the above "Setup and Testing" section. 

Version 1.3 - September 1, 2002
  *  Add 3D plot function via the EZNEC, 4nec2, or NevVu (Nittany) viewers.
  *  Remove restriction concerning minimizing the main EZNEC window.  The EZNEC
     window will now be automatically restored if necessary.
  *  Combine the functions of the 'Import' and 'Open MultiNEC Type File' buttons
     into a single button named 'Open Model File'.  Combine the functions of the
     'Export' and 'Save MultiNEC Type File' buttons into a single button named
     'Save Model As'.
  *  Add option to include a real-world (with losses) feedline with the model.
  *  Add Smith chart.  

Version 1.4 - October 25, 2002
  *  Add interface to the Antenna Model program by Teri Software.  A.M. may be
     used to perform calculations for a model, to view the geometry, to show a
     3D plot, and you can 'Open' and 'Save As' models in A.M. (*.def) format.
     Models in any recognized format (EZNEC, NEC, MMANA, ELNEC, AO, Nec/Wires,
     or the A.M. format) may be calculated using the A.M. engine or any of the
     supported EZNEC or NEC engines, except that A.M. cannot process models that
     contain ideal (NEC-type) transmission lines.
  *  When reading MININEC type files (MMANA, ELNEC, AO, or A.M.), automatically
     convert sources located at wire ends to "Split" sources if necessary for
     use with EZNEC or NEC engines.
  *  Add an "Insure Even" option to the AutoSeg function.  Show the total number
     of segments at the top of "Segs" column.
  *  Modify the legends for the R/X, SWR, and Custom charts to clarify whether
     the data reflects the impedance and SWR at the antenna source or the
     impedance and SWR as transformed with a user-defined feedline.
  *  Show the model file path and name on the Excel window title bar.
  *  Fix bugs in AutoSeg, Rotate, and Feedline for international users.
  *  Add option to change the model units while keeping the same physical sizes.
  *  Add function to change the min/max scale values on the Custom chart.
  *  Up to four snapshot lines may now be shown on the FF Plot, Smith, and
     Custom charts.  In addition, you can save and recall trace lines to an
     external file.  For the FF Plot sheet these traces are saved in OpenPF
     format.  Hence you can view them with other programs that can recognize
     this format.  You can also use MultiNEC to view trace files saved by the
     EZNEC and Antenna Model programs since they too are in OpenPF format.
  *  Add option to show the FF Plot with a linear dB scale.  The linear scale
     has gridlines (rings) every 5 dB.  The ARRL log scale now has gridlines
     marked in the same sequence as is used in recent ARRL publications.
   


73,
Dan Maguire  AC6LA
2150 Louis Holstrom Dr
Morgan Hill, CA  95037
Email:  ac6la@arrl.net

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