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Base Jogunn 8+8 Star series

BJ, thanks for the questioning the model.

I checked and the model is not reliable. I did it back in 2013, and I had several versions of that same model, looks like work in process, at that time. So, no telling what happened.

I should have checked the model more thoroughly before I posted it. The model is not even set to be vertical and the match is terrible.

I will do some work on this one and see if I can make it better, and then see if it is worthy to post. Sorry Hammer and the other guys.

Thanks BJ radionut.
 
Marconi: Not so much questioning your model itself, more the results.
If you get my meaning.
You have far greater use and experience at that software than I, just looking at the results of the model.
They seem to show the antenna has a very strange pattern, due to it's design. (the "Y" shaped element configuration)
I am more questioning how you can get a True Vertical or Horizontal pattern out of the whole design.
Thanks , no distrust intended or implied on your part.
All the Best
Gary
 
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From a technical standpoint, I'm unable to consider any dual polarity beam that uses 1/4 wave ground plane type elements for the vertical side and "horizontal elements" that are on a 45 degree inverted V angle, which cause a 3db drop in the horizontal polarization due to being half, cross polarized, while they serve as the 45 degree ground plane for the 1/4 wave vertical side. Just saying...
 
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BJ, here is my re-worked model of the JoGunn Star 6 with horizontal polarity, at 36' feet over Average Real Earth. I isolated the mast 3" below the bottom of the lowest slanted down element. I also added a choke to the top of the supporting mast to minimized currents on the mast. I added an image of the Eznec Control Center showing the Free Space Average Gain results...AG = 1, and that means the model is consider acceptable for the reported gain.

I also added an image of a copy of the JG manual. It probably came from one of the two guys I once knew that owned this antenna. I found his dimensions to be short so I change the element lengths by an inch or so...so the reactance was closer to resonance at 27.205 MHz. He either forgot to measure the short stubs in the boom that hold the slanted down elements or he was operating well below the 11 meter band. His reactance was X = -27.68 ohms with the dimensions noted on the sheet from the manual posted below. He was probably one of the locals that ran lots of power below channel one back in the days.

Sorry, there is no surprise that the model does not produce the gain that JoGunn reports at this link. https://www.jogunn.com/antennas/star-series/

I also checked-out for errors, an old Maco M -106C model I had made, so I would have something for us to compare. But, I forgot to include the overlays in this post. Maybe later. Working with multi-element beams is not easy...trying to watch for missteps and all those wires.

The JG model bandwidth is very narrow. If I added a physical Gamma to the model instead of the simulated gamma, the bandwidth may show better.

The Maco is about 5' feet longer than this JG so it did a better job in gain. The JG shows a much better rejection and when that happens the forward gain typically suffers a bit. JG wants us the think their beams give superior results in both categories, and I don't think that is going to happen. This JG model also shows a much better elevation pattern than my model of the Maco M106C. The overlays will show this difference.

BJ, your comments are always welcome bud. I feel good when I learn something.
 

Attachments

  • JoGunn Star6HwSGwMwISOwC 36'.pdf
    1.1 MB · Views: 16
In the PDF file below...are the overlays of the JG 6 and the Maco 106 for comparison.

The Maco M106C boom is 31' feet long as noted below.
http://macoantennas.net/Antennas.html

The JG Star 6 boom is 25' feet long as noted below.
https://www.jogunn.com/antennas/star-series/

This difference in the boom length, looks to make a 1* degree difference in the TOA, and it could also account for some of the difference noted in gain. The difference in the rejection with the Maco could also be effecting the difference it makes in gain and it does not look good. If the rejection was made to look better, that would likely take away some of the gain...so consider that too.

I use to have a CB buddy in Bridge City, Texas, right on the river that borders Texas and Louisiana. and located on a Bay about a 100 miles as the crow flies. He had a Maco VQ2 Quad with a azimuth/elevation rotor...that could change directions and lay the antenna over so the driven element was pointing straight up making the antenna vertical and back to horizontal again.

On my 4 element horizontal yagi I could hear and talk in either position, but the best signal was of course horizontal with my beam. On my Starduster, sometimes if he switched polarity he was gone when he slowly got on the flat side, but he would tell us he could still hear us on our verticals with his little two element V Quad up about 50' feet on a telephone pole.
 

Attachments

  • Overlays for JoGunn Star 6 vs. Maco M 106C both horizontal..pdf
    494 KB · Views: 12
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Marconi said:
BJ, here is my re-worked model of the JoGunn Star 6 with horizontal polarity, at 36' feet over Average Real Earth. I isolated the mast 3" below the bottom of the lowest slanted down element. I also added a choke to the top of the supporting mast to minimized currents on the mast. I added an image of the Eznec Control Center showing the Free Space Average Gain results...AG = 1, and that means the model is consider acceptable for the reported gain.

I also added an image of a copy of the JG manual. It probably came from one of the two guys I once knew that owned this antenna. I found his dimensions to be short so I change the element lengths by an inch or so...so the reactance was closer to resonance at 27.205 MHz. He either forgot to measure the short stubs in the boom that hold the slanted down elements or he was operating well below the 11 meter band. His reactance was X = -27.68 ohms with the dimensions noted on the sheet from the manual posted below. He was probably one of the locals that ran lots of power below channel one back in the days.

Sorry, there is no surprise that the model does not produce the gain that JoGunn reports at this link. https://www.jogunn.com/antennas/star-series/

I also checked-out for errors, an old Maco M -106C model I had made, so I would have something for us to compare. But, I forgot to include the overlays in this post. Maybe later. Working with multi-element beams is not easy...trying to watch for missteps and all those wires.

The JG model bandwidth is very narrow. If I added a physical Gamma to the model instead of the simulated gamma, the bandwidth may show better.

The Maco is about 5' feet longer than this JG so it did a better job in gain. The JG shows a much better rejection and when that happens the forward gain typically suffers a bit. JG wants us the think their beams give superior results in both categories, and I don't think that is going to happen. This JG model also shows a much better elevation pattern than my model of the Maco M106C. The overlays will show this difference.

BJ, your comments are always welcome bud. I feel good when I learn something.
Click to expand...
The measurements in the image are accurate as far as you know? Are the measurements between elements measured C/L -C/L? Thanks
 
20210620_163313.jpg So it looks like my luck has changed.
A long time Tampa local has left radio and sold all his shit. I bought his Jo Gunn 8x8 star set up which can be configured any way i want. Since i have all the elements for the star im thinking of buying the cross elements and then build it as a true flatside yagi and store the rest of it.
 
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The20poundhammer said:
I had a 5+5 Star up back about 2000 or so and i was really impressed with the construction. I changed over to a 4 element quad which works great but ice is not their friend lol. I am going to put up a large antenna of some kind and am looking hard at this one.
Click to expand...

20Pound,
Curious as to what you ended up putting in the air.

73
 

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