DG7YBN / Ant.-Soft / Antenna Modelling Software
  Last Update July 05th 2016




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In general about EZNEC, 4nec2, MMANA and others
Sample of how front-end and kernel work together / 4nec2
EZNEC / Same show, different front-end
MMANA-GAL Basic / Same show, different front-end, mininec kernel

Add-On's for Antenna Temperature & G/T computing

Program TANT for EZNEC & 4nec2
Program TANT - Unusual Application by UR5EAZ
Program Noise.exe for MMANA-GAL

Convergence challenge

Convergence problems and AGV correction per KF2YN

Model Segmentation

What the NEC2 manual says about wire segmentation

Miscellaneous

4nec2 & GNUplot installation and how to fetch data for use in MS Excel
How to fetch data from MMANA for use in MS Excel


Antenna Modelling and Analysing Software

Preface

This website shall give newbies to antenna modelling an overview on the most frequently used programs.
But I also show a few details that are essential for a deeper understanding and correct judging of antenna
models setup and properties verification that are not included in everybodies standard repertoire.

The big 3 in ham antenna modelling software are EZNEC, 4nec2 and MMANA-GAL. Apart from these there are
YO, AO and also NECWin Plus, NEC2GO.
There are other, non nec or mininec kernel based programs. And other EM (electromagnetic modelling) software
based on 'mesh engines' such as FEKO EM, Ansys HFSS, Sonnet EM which do cost a pretty buck.

It must be mentioned that the commercially discontinued AO Antenna & YO Yagi Optimizer by K6STI due to its
features handling tappered wires, mounting brackets, optimiser and wires meeting at angles (YO only) is a
(not existing any more) option to which many designers who have it stick to. YO models Yagis with straight
elements only, AO models any antenna. Both are DOS screen programs.

I also mention Yagi Analysis by SM2IEV, because in its time it made an impact on the VHF /UHF Yagi
developer scene. As it was and is the only Yagi-Uda antenna modelling software that includes producing
the Antenna_G/T. Though it is not as accurate with Antenna Temperature and G/T as the TANT program
in combination with reading the 3D pattern from EZNEC or 4nec2. Thanks to this feature it gave, lets
call it an early insight view on developing better Yagi stacks for earth-moon-earth operation.


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Front-ends to the solving engine: In general about EZNEC, 4nec2, MMANA and others

This chapter is written with a programmers view (I do industrial programming for 6 years now to earn my living).
But I find this approach quite useful to understand how the issued software works, which is the first step to
improved handling of such.

Antenna modelling software based on nec2, nec4, mininec kernels is a front-end to the named kernel.
We could say these softwares are 'User Interfaces' that handle a data set, namely an antenna geometrie and a command
to compute something to the kernel, which does the real work. Finally they handle the kernels output into charts or plots
when the calculation are done.

This is why for instance 4nec2 and EZNEC show the least of marginal aberration when we compare pattern or Return Loss plot output.
Provided both run same setting and kernels, like option 'Use Extended Thin wire Kernel...' (in the nec cards this is line 'EK'.
Which by standard is 'turned on' in both EZNEC and 4nec2. Only when opting for the Standard Thin Wire Kernel the 'EK' line is added to the nec wires card

Here is a useful report about the 'Thin wire Kernels', yet again by L. B. Cebik, W4RNL

The kernel is fed with the geometry of an antenna design. In a strictly formatted table.
As the kernel is programmed in Fortran and needs to be fed with commands and parameters according the nec cards
description in the NEC Manual. It is the front-ends task to provide a useful interface like a table calculation like
geometry input or a geometry orientated editor and transform this into the NEC Cards tables before feeding the kernel.
It is understood that the genius of computing the antenna properties lies at the employees of the Lawrence Livermoore
Laboratories that coded the NEC Kernels. But it is also understood that the genuis of providing a convenient human machine
interface lies at the makers of said antenna modelling software. As before that punchcards needed to be produced and
fed to crude computation machines. That is why NEC Cards are called NEC Cards. Because in the beginning they were
hard paper punchcards.


Of coarse it is the same mechanism with mininec based front-ends i.e. antenna simulation software.
Just with some mininec specific details now. Understanding this we see that it does not come down to the
question whether 4nec2 or EZNEC are producing the better numbers, because both use same engine or kernel.
So that their output is identical except possible rounding errors on the very far end of decimal float values
variables the programs are handling.







Sample of how front-end and kernel work together / 4nec2

I have chosen 4nec2 for this first example because in this software we find a separate window for each step of the
'communication' between kernel and user interface = front-end. Which for newbies to 4nec2 might be more
confusing then with EZNEC but can be an advantage for the experienced user, or after having read this acticle hopefully.

   Read a step-by-step description how 4nec2 operates the nec kernel







EZNEC / Same show, different front-end

   Read a step-by-step description how EZNEC operates the nec kernel







MMANA-GAL Basic / Same show, different front-end, mininec kernel

With MMANA the handling is slightly different, as here we do not see a set of windows but
pages on a single userform or GUI (Graphical User Interface) in programmer speak. Besides that we find
the same mechanism as with the most spread nec kernel based front-ends EZNEC and 4nec2.

   Read a step-by-step description how MMANA operates the nec kernel







Antenna Temperature & G/T computing Program TANT for EZNEC & 4nec2

TANT was progammed by YT1NT, on proposal of YU7EF and with help from YU1CF + YT1NP.
It is small in size a DOS console program that does not need an installation but can be run
from any drive as it is.

   Read about the program TANT.exe for Antenna Temperature and - G/T computation from EZNEC and 4nec2 files


   Read about an 'unusual application' of TANT.exe focusing terrestrial communication by UR5EAZ







Antenna Temperature & G/T computing Program for MMANA-GAL

Noise.exe is a program developed by Kosta, UR5FFC, 'Black Sea Radio Co.'.
It is a small in size 'windows' program that does not need an installation but can be run
from any drive as it is.

   Read about the program Noise.exe for Antenna Temperature computation from MMANA files







Convergence problems and AGV correction per KF2YN

We want 'realistic' antenna simulations. Of such kind, that they can be produced as real antennas.
But the simulation output varies a great deal with the wires segmentation number of the model.


   Read about the challenge of getting the models segmentation right







What the NEC2 manual says about wire segmentation

   Read about proper wire segmentation







4nec2 & GNUplot : Installation and how to fetch data for use in MS Excel

   Read about GNUplot, 4nec2's data exchange and table calculation applications







How to fetch data from MMANA for use in MS Excel & 'MMANA_Plot' MS Excel sheet

   Read about MMANA's data exchange and table calculation applications











73, Hartmut, DG7YBN


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