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Discussion Starter · #21 ·
I know the antenna modelers do this all the time, but it's daunting to me.
I looked at Nikiml's tutorial and he says to use 4nec2, and not sure where to find it.
Next he says you'll need Python 2.6 or higher and to install that. Is that true?

I take it that 4nec2 is the program, and perhaps this link contains the data? www.mediafire.com/folder/vput2t50a1jmg/nec_opt
or is it here? nikiml's Antenna pages - Nec Viewer

Downloading and unzipping is fairly easy, but I'm afraid that as a newcomer, I'd need some help with a step by step , and maybe there's one out there on digitalhome?
 

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If you want to make modifications and test them then yes you'll need the other stuff.

But if you just want to view the existing stuff, download/extract the website rar from the mediafire link, open the index.html, and check out the antennas on the site. When you click on one it should load it in the built in NecViewer so you can see distances/angles for building.

Alternatively, you could download a *.nec, open up in notepad, and past everything into nikiml's Antenna pages - Nec Viewer
 

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Discussion Starter · #23 ·
Wow. I feel that my blinders have lifted and I can see what many of you guys have seen all along!
Thank you so much hamiltonota!

So now we can hopefully both look at some dimensions which have eluded me, and which other forum members have intrepreted differently in their construction plans for their gh10ns.

Using the www.mediafire.com/folder/vput2t50a1jmg/nec_opt model gh10ns, I see the height of the top narod is 67mm, delta z. however on post 72 of the 900 post narod thread, Nikimil reported a dimension.at 107mm or his h value there.
Likewise in post 72 the width of the top of the narod is shown as 302mm, value a, but in the nec gh10ns model it shows as 369mm if delta y is the right value there
In the nec model the distance from the lowest of the 3 rear reflectors to the middle reflector shows as 484mm if delta z is the correct value. On Nikimls post 72, he shows 371mm for z.

So one of the following is true:
A: I'm on the wrong model
B. I'm measuring the distances incorrectly
or C: and most unlikely, Nikiml shows different dimensions for the gh10ns, or the gh10ns was revised

probably my error!
 

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There's different versions around. The earlier one you are talking about may be an earlier or different version; which would have slight different dimensions. As long as you stick to one model to work from you should be good. The Non Modular section you are in is the one I used to build my first one.

Have you tried the rabbitears site? It should show you what should be possible to get. A lower GH# number is a little bit easier to build and almost as good.
 

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Discussion Starter · #26 ·
HamiltonOtas info is invaluable and much appreciated ! After building an early gh, I hope to now build as accurate as possible gh10ns. (I've built 2 person aircraft from scratch, and somehow I think the gh dimensions are similarly important, except an antenna won't kill you)

Here's the dilemma. Comparing drawings of the gh10ns from 2 experienced forum members, with jed's and Nikiml's, I get 4, that's correct 4 completely different sets of dimensions for gh10ns.

Looking at the top 3 angled dimensions of the active element (jed's a3, a2, a1), Nikiml shows them in decending order as 124, 139, and 158mm.
Jed says 190, 192, 196.
UncleSam says 176, 197, 223.
Asahjaya says 178, 211, 221.

One would think the active element has the most critical dimensions, but these 4 reliable sources have dimensions varying up to 60mm. Performance must vary a great deal.

Pretty sure I read that Nikiml based his models 100% on Jed's work, yet looking at Jed's very clear website, it seems few if any are actually using his figures, unless I'm missing something.

Just hoping to get this right.
So, what to do?
 

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I seem to recall from when I took a deep dive into this, I was able to view nec2 files in my browser (Firefox at the time) through a script environment called Greasemonkey that ran the necessary Python stuff…
Maybe this helps some of you following along.


Sent from my iPhone using Tapatalk
 

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Discussion Starter · #29 ·
HamiltonOta has skillfully led us to Nikimls drawings and they are easily viewed.

Now I see what looks like conflicts between Nikimls latest gh10ns drawing and jeds very clear gh10 drawing on jedsoft.org.

Particularly the antenna active elements a1, a2, a3 seem as much as 65 mm off.

Since Nikiml based his work on jeds designs this appears to be a conflict.

I wonder if someone experienced in testing models could test Nikimls gh10ns as found here
www.mediafire.com/folder/vput2t50a1jmg/nec_opt
or is it here? nikiml's Antenna pages - Nec Viewer
Need to insure that a3, a2, and a1 show up as 124, 139, and 158mm respectively , also that delta z is 484mm, so we know we're on the same page.
 

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I don't like those monstruose VHF/UHF GH. Very big and costly to manufacture. Cheap and tiny VHF+UHF Yagi + UHF/VHF diplexer/combiner perform better.
GH has huge rear lobes from +3 tp +8 dBi, very dirty side lobes.
Huge rear lobes mandate clear space behind antenna. Otherwise distort antenna properties.
Cheap and robust Yagi has small rear lobes, can be mounted at the wall, roof or behind pole/mast. No need for clear space.

 
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