Tag Archives: Antenna Modeling

Buying a NEC-5 License for Antenna Modeling – Lawrence Livermore National Laboratory

Buying a NEC-5 License for Antenna Modeling – Lawrence Livermore National Laboratory, you get to work with Mary Holden-Sanchez, who is super nice as well as efficient.

As of mid-May 2022 the process is you should fill out the three forms and get them to Mary by email. Several are pdfs that you can fill in online prior to saving them and sending them. On the long license form fill in everything you can BEFORE you let Adobe do its eSignature part, as there are parts to be done after the signature page.

I withheld some of my credit card details rather than sending them via email, and I called in the missing parts.

Lawrence Livermore National Laboratory can also do payment via DocuSign, an interim solution providing much better security for your credit card details. To request the DocuSign process, email Mary.

They are in the process of implementing a secure online payment system.

The link for NEC-5 is https://ipo.llnl.gov/technologies/it-and-communications/nec-v50-numerical-electromagnetic-code

The May 2022 contact, and Mary’s information is:

Mary Holden-Sanchez, IP Specialist
Innovation & Partnerships Office (IPO)
Lawrence Livermore National Laboratory

My experience is that the system has an unusual number of moving parts, that adding the financial security will be a boon for the payees & LLNL, that some of the people are working from home, and that at this time the payment part is done by finance separately from licensing.

When everything goes through, you get an email invite to your portal where for about the 3rd or 4th time you get enter your contact information before you can download the files.

As it was, I missed the daily cutoff for payment processing and it took a day to get my license.

On the plus side, they have a really great product to license and I got to speak with good people!  I’ll touch how to add NEC 5.0 X.13 to your installation of EZNEC in another post.



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More on Antenna Modeling

The previous post on EZNEC being offered gratis to the Amateur Radio community had some comments, and I received a few emails. (Link https://k9zw.wordpress.com/2022/05/14/eznec-antenna-modeling-for-all-of-us/ )

Much of what had been in computer antenna modeling has changed over time.

I gathered as many links as I could find for this post.  If you know of additional programs or links, please put them in a comment, and periodically I will edit them into the main post.

(NOTE:  Focus is on general HF Amateur Radio level usage programs)

Antenna Modeling Links – mid-May 2022:

Active Programs Found

Linux Active Programs Found

Links that work, but the programs are not fresh (may be DOS or WinXP):

Replaced by newer offerings

Defunct Links

  • NEC-Win-Plus – defunct was Nittany Scientific, who is out of business
  • NEC4WIN – defunct – was Orion Systems
  • SuperNEC – defunct

About NEC (the engine at the center of these programs)

NEC Alternatives/Derivatives

Other Useful Links:

ARRL Links



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EZNEC Antenna Modeling for All of Us

I missed this while it was happening. I was looking to update my old software to model my new antenna configurations and found out about the change.

As Roy W7EL decided to retire, he made public his EZNEC antenna modeling software (compiled form only).


There is also some neat stuff on NEC-5 end, where there is a collaborative update to the latest version (NEC5 X11) thanks to some great ham inputs! https://eznec.com/NEC-5.htm

The AC6LA add-on AutoEZ is something I plan to check out. https://eznec.com/AutoEZ.htm and https://ac6la.com/

AutoEZ is interesting as it an an Add-On to EZNEC which in also in essence an Add-On to NEC.  AutoEZ appears Excel-based, EZNEC is Visual Basic 6 (obsolete version) with some Fortran modules,  and the core NEC compiled Fortran (Intel Visual Fortran with the mkl math libraries).

Below the “–” line I will include some background from either Roy W7EL (website archived copy or QRZ.com) or a QSO Today Podcast interview he did with Eric 4Z1UG.

Well worth checking out all of these programs.

Also a series of dedicated books by ON5AU that should be considered if you are going to put EZNEC to work:



GL and 73


Continue reading

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4nec2 – NEC based antenna modeler and optimizer by Arie Voors

An opportunity to run NEC2 Antenna Modeling without buying a commercial program or tracking down an archive of a long unsupported program:

4nec2 – NEC based antenna modeler and optimizer by Arie Voors

4nec2 is a completely free Nec2, Nec4 and windows based tool for creating, viewing, optimizing and checking 2D and 3D style antenna geometry structures and generate, display and/or compare near/far-field radiation patterns for both the starting and experienced antenna modeler.

When running frequency sweeps, linear or logarithmic style SWR, Gain, F/B-ratio and impedance line-charts are produced. With the included Optimizer and Sweeper one is able to optimize antenna- and/or other environment-variables for Gain, resonance, SWR, efficiency and/or F/B, F/R-ratio. With the sweeper one is able to graphically display the effect of changing one or more of these variables for a specified range of values/frequencies.

For the starting modeler a graphically based 3D geometry-editor is included which requires no additional NEC knowledge while still enabling you to create and visualize and compare current-distribution, far/near-field patterns and Gain/SWR charts. More experienced modelers can use the gradient style and/or the genetic algorithm based optimizers to improve their designs.

Check it out!



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Dayton Hamvention 2008 Follow-Up Report No. 11 – EZNEC Antenna Modeling


I’ve been long interested in Antenna Modeling, and had started using EZNEC-ARRL as part of the ARRL CCE Antenna Modeling Course.

As I recently wrote about, I’ve also been using CocoaNEC on a Mac.

In both cases I have been approaching program limitations with some of the full-station modeling I have been trying.

EZNEC Version 5.0+ seemed to be the best fit for the modeling projects I am attempting and after discussion with Roy Lewallen W7EL I took the plunge & bought his latest version.

One must remember that NEC2 itself is limited and no “shell” surrounding the NEC2 core can overcome those minor limitations.

From Roy W7EL’s website:

The best way to get acquainted with EZNEC is to download the free demo program. It’s a complete EZNEC program except limited in the complexity of antenna it can analyze. With it, you’ll quickly learn what EZNEC can — and can’t — do for you.

Information About the Free EZNEC v. 5.0 demo version

ARRL has version 4.0-arrl included with the ARRL Antenna Book as well.

Now it is up to me to make good use of this tool!



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Bruce Array Antenna Modeling – cocoaNEC Version

40m Bruce Array - 3D presentation

Working at modeling the new Bruce Array for Washington Island

Here are PDF files of the various outputs from my first efforts in cocaoNEC:








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