Free Utilities for Nec2Go
Home: KY8D.net
Last updated: 2020-07-27
A short but eventually growing list of free utilities intended to suppliment the $39 NEC front-end analyzer software Nec2Go. These are programs I wrote for me, but which you are welcome to share for free, source code and all.
My N2P_to_SVG.exe utility generates highly detailed, large-format, azimuth and elevation gain charts in Scalable Vector Graphics format. Not just one at a time, but in whole batches. Do that like so:
- Have a directory of one or more
*.ant files.
- At a command prompt, enter
"c:\a\b\nec2go.exe" c:\x\y\ and return.
- Whatever may be the directory paths for Nec2Go and your target
*.ant file(s).
- One or more
*.n2p files plus a single OutputBatch.txt file will result.
- Drop a copy of
N2P_to_SVG.exe into that directory and double-click it.
- If special arguments are wanted, those may be passed via the command line.
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SVG Charts ↑ ↓ →
You may click on any of the above to see the image at its full size. They're all the same file, and only just 56,536 bytes. At 900x900px, the SVG master file might seem a bit oversized. That large by intent, so as to be having more dBi rings. Had I asked the utility to provide smaller, it would have done. Any size whatsoever I asked for. But then, I'd have got fewer rings. It manages ring count by how large of an image its asked for. So either 10, 5, or 3 dBI for each ring with increasing size. And the number of rings being always the next one beyond maximum gain. So then, not normalized. That way on purpose. And if the divisons should be 5 or 10, then you'll get a dotted green circle at 3dBi. And, of course, you can scale up as well as down. SVG just doesn't care.
Choosing a very large size, such as above, would normally be for when you're wanting to submit a chart along with your article to QST or QEX. Something like that. Remember that while your computer screen is likely 96 pixels per inch, a common printer is instead 300 dpi, and a CYMK magazine format might be as high as even 1200 dpi.
Be aware that for insertion into MS Word doc (version 2016 and later), you'd first be needing to convert from SVG to EMF (Enhanced Meta-File) image format. Which is easy enough, with no quality lost. Just use Inkscape for that, as mentioned further down this same page.
Be pleased to know also that all modern web browsers support SVG, Firefox and Chrome distinctly more prettily than does MS Edge. Natrually so, since Microsoft seems always to lag behind. Just like how took MS Eplorer nearly forever to at long last not gray out transparent layers on PNG. Compare, for instance, how only on Edge does the very thin border of my charts sometimes disappears. I could make it thicker so as to help MS Edge out, but at the cost of uglifying my charts everywhere else. Alas and alack. I'll leave them as is. Yet should yoube wanting those borders either thicker or gone, that too is easily done via Inkscape.
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How it Works ↑ →
My little software utility, N2P_to_SVG.exe file contains a Perl script inside. That plus just enough Perl to make it go. It is Perl which generates text for SVG files. So should you prefer (and also be having Strawberry Perl installed on your PC) you then could rename from N2P_to_SVG.txt to N2P_to_SVG.pl and run it that way instead. Also, edit the code to change what you like. Or rob me blind by stealing the program wholesale. Just as you please. I do not care.
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User-Editable Text ← ↑ →
The SVG format is a stubset of XML, and so, pure ASCII text. The entire SVG file, nothing but text. And for each corner of the chart, I have embeded three rows for text. Some of those the script itself fills with data from the N2P source file.
Therefor feel free to edit the SVG file employing any plain, ordinary text editor. Just not a full-featured word-processor. Then hunt down-file to the very bottom searching for the XML text tags. They look like so...
<!-- Below is the text for 'btm-lft', row '0'. -->
<text x="-69" y="975" style="font: 30px sans-serif; white-space:pre-line; text-anchor:start; fill:black;">Sommerfeld-Norton Ground< ext>
...where the green is an XML comment, the red below it is XML stuff best left alone, but the blue you may do with just as you may please. If, that is, there is any blue text at all. It might just be empty, there for you to be adding in extra text, as you choose.
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Scaling ← ↑ →
Say I have two image files, an SVG and a JPEG. And both are 400 pixels wide. In an HTML or XML web page, to make either one display at half size, I ought get away with treating either exactly the same. Like so...
<img width="200px" height="auto" src="./foo.jpg" />
<img width="200px" height="auto" src="./bar.svg" />
But on the proprietary Samsung Internet browser of my Galaxy S20 smartphone, there is a bug. And an SVG viewed on it doesn't scale. The <img> tag's scale factor just gets ignored. An all-browsers workaround would be to edit the SVG's own scale factor instead. On the second line, edit like so...
<svg width="200" height="auto" viewBox="-90 -90 1080 1080" xmlns="http://www.w3.org/2000/svg">
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Inkscape ← ↑
Not my softwere, just sharing info. Inkscape is a free, open-source drawing program whose native format is SVG. On its own website, the version is listed as 0.97. Which is not at all an indication of beta software. Inkscape has existed for decades. It's just that they follow a sane version-numbering system. Never once have they broken the original GUI. Never once have their users had to stop using Inkscape in any particular way.
So changing that 0 instead to a 1, would be an alert that the new version changed something drastic, and its users adapt. So the 97 updates below that 0 were all of them minor bug-fixes and improvements. Part of how Inkscape managed that, is that Inkscape itself forked off from another program already mature. Sodipodi it was called, which I had used to use also on an OS called NetBSD Unix, and on my Amiga 2000 computer before even then. The fork, as I only vaguely remember, had to do with the Inkscape folks wanting to more strictly adhere to XML standards for SGV, which the author of Sodipodi had not done quite entirely.
You can also use Inkscape to convert from SVG to the EMF format. Which is needful if you are wanting to insert them into an MS Word document. As always, Microsoft just had to be different. But at least in this case, it is easily got around. Follow the directions which you'll find here and the result will be very pretty.
Inkscape So, then, get Inknscape, and thumb your nose at the high-priced offerings of commercial vendors. Click on the button. Install Inkscape, and ever afterward draw freely!
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HTML Index ← ↑ →
SVG Index Check out the button at left. For even as my little program is parsing its way through Nec2Go's N2P files, generating an SVG graphic for each, it is alas, at the same time generating a solitary HTML file to serve as index for the whole lot. Those charts depicted in the example are the result of my turning Nec2Go loose on a batch run, churning through all of the sample antenna files which come packaged with Nec2Go.
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Command Line Args ← ↑ ↓ →
Double-clicking the starling icon equates to the below...
N2P_to_SVG.exe --size 900 --path .\*.n2p
...meaning SVG charts to be 500x500 pixels in size, and a chart for every *.n2p file in the current directory.
If not wanting that, you must call the program on the command line. For example, like so...
N2P_to_SVG.exe --size 750 --ring 12 --path C:\Users\KY8D\Desktop\Ants
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--size ↑ →
All plots occupy a square, N pixels on a side. Calling --size 750 instructs the SVG to say that it's to be that many pixels on a side. Not that you can't change it later, since all that really happens, is that inside the SVG will say width="500" height="auto".
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--ring ← ↑ ↓ →
Floor-magnitude of the plot's outer ring. In multiples of 12, 6, or 3 dBi, depending on how many pixels in size. Ask for --ring 11 and you'll get varied results. A balance will be struck so as to avoid crowding small charts with too many rings, and lakes of white in large charts from not enough rings. So then, as below...
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Smaller Charts ↑ →
Outer ring = 12. Descending rings of 0, -12, -24, -36, -48.
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Medium Charts ← ↑ →
Outer ring = 12. Descending rings of 6, 0, -6, -12, -18, down to -48.
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Big Charts ← ↑ →
Outer ring = 12. Descending rings of 9, 6, 3, 0, -3, -6, down to -48.
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Default ← ↑
Not calling --ring at all is the default. Each plot in turn will scale independently. Outer ring will be as small as the antenna's max dBi allows.
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--path ← ↑ →
Either a directory path, or else the path to a single file. Something like either of these...
--path C:\here\there\
--path R:\far\further\LPSA_11-elem.n2p
Relative paths, and/or forward slashes are no problem. But paths with spaces must be in quotes
--path "./New Folder/My Antenna.n2p"
And yes, case does matter. Don't be ignoring the shift key.
Needless to say, if it's just a file name, instead of a path, that won't work.
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--norm ← ↑
Future option not yet implemented. Perhaps even never. For normalized charts, such that the outermost ring is equal to the max dBi of each antenna individually. While providing best display of the plot's shape, it is less avantageous for comparing one antenna against another. Not important to me at present. I might be pursuaded, however, if the case were pleaded with sufficient conviction to warrant two days of my time. Send me an email.
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A GUI Maybe? ← ↑ →
This might be waiting a while. It's on my to-do list, but 2nd-to-last on that list.
My own plan is to call this utility always by CLI (command-line interface). Or, rather, to have yet other programs do this for me. GUI-enabled stand-alone antenna calculators, custom-coded in LabVIEW. One such for log-periodic antennas (several kinds) is now nearly finished.
Emails from users might well suffice to pursuade me.
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Download ← ↑
ZIP Click button at left to download as ZIP. Inside will be an EXE file, plus also the source code in Perl. No rights reserved.
I have a script likewise which does also this. After a batch run of plural *ant files performed by Nec2Go, this little utility will parse through the file Nec2GoBatchOut.txt generated by Nec2Go. Having done that, it will output a spreadsheet in CSV format.
Elsewhere I mention how much I hate messing around with spreadsheets of any kind. I don't count this as messing around on account of only wanting to view it. An automatically self-built spreadsheet is a very fine thing indeed. So long as I need not subject my poor wrist to hovering over hundreds of cells with a mouse. Short of that, I don't really hate them nearly so much.
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Download ↑
ZIP Click button at left to download as ZIP. Inside will be an EXE file, plus also the source code in Perl. No rights reserved.
In the same category as EZNEC, 4NEC2, and MMANA-GAL, Nec2Go is yet another front-end GUI to the otherwise very unfriendly raw Fortran of NEC. And of the four, I'm now liking Nec2Go best of all. Pat, W0OPW, is the author. His program gives answers notably faster. SWR plots build, point-by-point, as I watch. This as compared to my $149 copy of EZNEC+ v6, which won't show me anything until the very last point has been computed. With Nec2Go, if that plot should start to look not-so-good, I can abort the run right then and there. Considering all I got for just $39, I can't help but think of Nec2Go as almost-free software.
I still like the others all well enough. But there are two things very important to me which Nec2Go has that others do not. Firstly is that, whatesover information I'm wanting, Nec2Go offers it up with fewer mouse clicks. A much enjoyed balm to my poor aching wrist. Not that I suffer from diagnosed carpal tunnel, but at the end of several hours on a computer, such must be a common complaint. I applaud Nec2Go's simple, ergonomic menu layout. Maybe not so pretty as some, but clean, straight-forward, and entirely true to its purpose.
Better yet even still is that Nec2Go can batch process an entire directory. Yes! Much like how I read of the venerable L. B Cebik, W4RNL having done, as described in certain of his treatises. So then, me too, in so far as ever I can. A double dozen antenna-file copies, all the same except for small differences in a given parameter I can now enjoy to compare with near-zero effort. These being the iterated output from a custom-built calculator of my own design. Log periodics in this particular case. To generate those might take half an hour of my program running in automated fashion with me AFK. After which, Nec2Go will post-analyze the entrire lot lickety split. How great is that for just $39?
Still, though, I thought Nec2Go would be even more handy were it to have a helper ultility or two. And these I have coded myself for my own use, but which (as is always my policy) I share freely. Any others I think of, and deem worth my time, I will likewise offer here. Absolutely, I'll be including the ANT file format (along with NEC and MMA) in any future type-specific antenna calculators I build in either LabVIEW or Perl.
Now, as this page is mainly for Nec2Go users, but might be found also by curious others, I'll hit on only just a few points, those most imporant to me.
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Speed of Execution ↑ →
Nec2Go runs very fast, providing extremely prompt answers. Very surprising when you consider that Nec2Go is just, yet another front end to NEC, which itself runs in Fortran. Nec2Go's author informed me as how his front end to NEC's Fortran does not make its own calls batch mode. The author himself personally refactored the NEC Fortran into separate sub-routines so as to allow calling them individually. And so Nec2Go, alone of all others, works by this fashion.
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Unlimited Segments ← ↑ →
Unlike EZNEC and MMANA-GAL, Nec2Go imposes no limit on segment count. For dipoles and such, that's never a worry. And lately my interest has been with log-periodic antennas. Sawtooth arrays in particular. Long-boom verisons with 18 wire-tooth elements on average. With my $149 version of EZNEC+, all too often I'd hit that wall. No choice then, but to reduce the segment count and pray it did not cost me accuracy. MMANA-GAL too has a segment limit. Not sure about 4NEC2. But guaranteed never a worry with Nec2Go.
And make no mistake, whenever there should be difference in results with only the segment count being varied, then have yet another go with the segment count evern higher. And so again until the differences are insignificant. Pat instructs I should say "convergence has been achieved'. This is something my $149 license for EZNEC+ v6 did not afford me a chance to learn. I'd get a pop-up warning, in effect, "Whoa, Cowboy. Just you back off now. Never any such complaint from Nec2Go.
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Why a Batch Mode? ← ↑ →
Pat, the author of Nec2Go, very kindly added this feature to his program at my request. That's useful in tandem with a calculator I've built. Not yet released, my calculator generates log-periodic antennas. Not just LPDAs, but ten different sorts. So at times I'll be wanting to figure out the best combination of several parameters. On LPAs, you have all these: tau, alpha, psi, boom length, element count, element type, height above grond, and ground-ward tilt. Far too many for my poor brain to sort out. More than simply relying on 'ideal sigma' can hope to account for.
Easier by far to simply to generate a few dozen files, each one of those just slightly different, then batch analyze the entire lot. The log periodic calculator I've written in LabVIEW takes some little while to produce a batch lot like that. But Nec2Go does its own part in a flash. Or series of flashes. Blink, blink, blink ... one blink per file. Like that at 30 segments per wavelength! And still not at all what I'd call slow even should I set the segement count quite a bit higher.
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Start From Scratch? ← ↑ →
A mistaken first impression I had, was that Nec2Go seemed to lack for the usual start-from-scratch utility of a wire-table spreadhseet. You know, like those to be found in its much better known three competitor NEC analyzer front ends. No spreadsheet for the user to manually populate. N Iot obvious to me at first (becuase of my failure to RTFM) is that with Nec2Go, you model by user-defined equations instead. Those same equasions which, were this one of those other NEC analyzers, you'd do on a hand calculator so as to have numbers for manually typing into their spreadsheets. The user defines their own variables, using those to define antenna elements. Which isn't, admittedly, how I've breen using Nec2Go myself. Being bull-headed, I ignore all that, and just call Nec2Go the way that I do because it is fast and convenient. In due course I will be trying out those special features. I'm just putting it off for until after I've polished off the LabVIEW calculator for log-periodics.
Truth to tell, never have I very much liked messing around with spreadsheets. Neither free-standing ones like Excel or Open Office Calc, nor yet any such as are built into any program whatever. Utter tedium. Plus all that mouse-work leaves my wrist aching. Those two things were my chief motivations when first I began designing custom calculators for specific antenna types. Not far from release is one I wrote for log-periodics. With output in plural formats (NEC, ANT, MMA and also IGES), happily do I avoid any contact with spreadsheets.
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Special Refinements ← ↑ →
On reviewing this page, Pat, W0OPW (the author of Nec2Go) suggested that I might at least make passing mention of certain features his users report very much liking that I have for the most part ignored. These would be:
- Variable definitions
- Sweep and Optimize of variables
- Pat insists this to be Nec2Go's real advantage over all others.
- Convergence and average gain test.
- Auto plot generation for Phi and Theta.
- Coax with loss definitions.
Pat's list was somewhat longer, but I'm wanting this page to remain chiefly about the helper utilities, I wrote, so will stop there. I share with you Nec2Go's user manual instead: PDF .
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Built-In Help Feature ← ↑ →
Not really there anymore. Not on Win10, anyhow. Nec2Go's GUI does still show one, but for having been built according to a now-abandoned Windows Help format, it's dead as a doornail on Win10. Which at first did prove somewhat an annoyance.
But instead of uselessly cursing the non-working button, I pestered the program's author by email. Pat is his name, and he's cheerfully provided prompt service whenever I had the tiniest question. Each of my surely tiresome queries has been courteously replied to.
And in any case, Nec2Go's GUI interface is simple enough. None of its features are deeply buried anywhere that's hard to find. Had I discovered its PDF manual right from the start, then I'd have had not so many questions.
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Little Quirks ← ↑ ↓ →
One thing which perplexed me at first, was that the GUI window seemed to appear shrunken and scrunched in upon itself. The issue was me failing to realize that Nec2Go was waiting for me to stretch it out to whatever larger size I preferred. Once I got around to that, Nec2Go has thereafter remembered that size.
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Command-Line Oopses ↑
Sometimes when meaning to run a batch mode, I'll mistype the target directory. How Nec2Go responds to my error, is by instead running a batch on the sample antennas in it's home directory. My fault, not its. But then, if not wanting to wait the minute-plus for it to finish, I might be so impatient as to just kill the program and restart. No harm has yet been done, however I've chosen.
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Where to Buy? ← ↑
Nec2Go Home Page Button at left links to the Nec2Go home page. Browse its features and decide for yourself. Without you have Nec2Go, however, nothing on this particular page will be of any use whatsoever.
Zero promises are herewith made or implied. I wash my hands of whatsoever cosmic disasters as may result. By using my software, you further absolve me of all crimes, both high and low, granting full and irrevocable. Should your computer (or head, for that matter) explode such as to breach the space-time continuum extinguishing life throughout every dimension, that's all on you. You got it for nothing, so that's the deal. With my software anyhow. Not sure about Pat. Take that up with him.
Generosity is not only listed first, but also held to be foremost among Lord Buddha's Six Perfections. Plus there's the fact that nothing sucks all the joy from a hobby faster than the taint of commercial expectations. So I'm earning a wee tiny smidge of good karma, plus also keeping it fun. Reasons enough.
