Re do on my I-10K post #3 and got unusual results.

[Marconi]

Well after I fixed the errors in post #2, I noticed the match didn't change much, so I decided to go ahead and try to fix the radials into their asymmetrical positioning as they are on the actual I-10K post #3.

After measuring and getting the model to agree with the angles and dimensions I took, and fixing the symmetry issue, I scanned the model and got the unexpected results noted below in the pattern view for gain and angle.

I was amazed to see the horizontal pattern emerge as the dominant lobe with a noticeably higher gain. The horizontal pattern is in green, the vertical is in red, and the black indicates the combination RF for the antenna.

Bob, from the very first time I tried my idea for the trombone tuner...I saw some modest horizontal RF appear in the 5/8 wave pattern, but I never saw it dominate like this. I posted something about this last year. I can't be sure, but what if that trombone does generate a lot of horizontal RF in its pattern?

Could that be the factor that Jay and Master Chief use to always crow about?

View attachment Asymmetrical models at 20' and 50'.pdf

This is the amazing revelation I saw today at 20' feet and 50' feet, after I made my I-10K model asymmetrical with the radials. :blink::blink::blink: and

Bob, if this model is even close to accurate, could this be part of the issue you notice with your I-10K mounted <20' feet...close to the ground, regarding your low angle DX?

 

[HomerBB]

Marconi. I looked at all three, and this is certainly an interesting development.

 

[BOOTY MONSTER]

in your i10k models do you have the matching trombone off to one side , or does the program see it as being symmetrical ? is the mast , coax and earth ground included too ? any coax choke ?

 

[Marconi]

in your i10k models do you have the matching trombone off to one side , or does the program see it as being symmetrical ? is the mast , coax and earth ground included too ? any coax choke ?

The first post showed a close up end view of the tuner, off to the right side of the mast. No! I know the I-10K is NOT symmetrical at all, but maybe that doesn't always hurt. I haven't checked the currents yet, but I suspect I'll find a lot of current flowing in the radials and the tuner, and that probably is what is causing the horizontal RF to dominate.

The the first time I ever saw horizontal RF in a vertical pattern, was when I first added the tuner to the I-10K, a good while back. I think I posted the model and talked to Bob about that issue.

Again today was the first time I ever saw horizontal dominate dominate the pattern and this model at 50' feet shows more low angle gain than any antenna model I have, but I'm not sure exactly what is going on yet.

I did not include the feed line, and I'm not able to model a coaxial choke. I can isolate the antenna from the mast using a small space, but that is not exactly the same. I might try isolating and see what that does for the pattern, good idea BM.

Yes, the mast is grounded, and so is the antenna to the mast.

Like I said earlier, I noticed this horizontal dominance after I made my model more unbalanced by making the radials A-symmetrical, just as noted in post #3.

 

[Marconi]

Marconi. I looked at all three, and this is certainly an interesting development.

Yep, it really surprised me. I always felt that symmetry is an unsung advantage in antennas that nobody hardly ever talks about, but this really blew my mind.

 

[HomerBB]

If it remains true to what the antenna actually does, it looks as if it would be an in-phase dual polarity antenna.

 

[Marconi]

If it remains true to what the antenna actually does, it looks as if it would be an in-phase dual polarity antenna.

I checked the currents and the radiator appears typical for a 5/8 wave radiator. The radials and tuner, however, are not in phases. The currents in the bottom around the tuner and radials are about double the currents flowing in the radiator and are out of phase with the top 1/2 wave and the top hat. That probably is where the dominating horizontal is coming from.

The mast also shows very little current flowing at .0258 A, over the whole 50' feet which appears exceptionally good for a grounded vertical. I think Exnec inputs 1.0 A, into their models.

Remember this is preliminary, and I could find a gross error somewhere. I have heard Tech 833 on Cooper's claim something similar going on in the tuner area of the I-10K, when he tested it on an antenna range. He's touted to be an RF Engineer of world renowned.

BTW around noon on today, Wednesday, short skip is working for me all over Arizona, Mew Mexico, Texas, Oklahoma, and Louisiana.