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Homemade Sigma 4 11 meter base antenna

bob85 said:
shockwave id not lose much sleep over the avanti guys comments, he could be the same avanti guy master chief talked to,

some time ago marconi purchased a back issue article about the avanti astrobeam,
i had high hopes it was going to prove my theory & explain in their own words how the astrobeam and astroplane worked since the front cover had a picture of an avanti engineer with drawings of that style antenna on the chalk board,

i was wrong and more than a little surprised, the avanti engineers admitted to NOT understanding exactly how it worked,

if they can't understand the astroplane they won't get the sigma either :)

CEBIK was right in everything he confirmed for me about the antenna and the people who will generate pages of meaningless argument because how it operates is not apparent to most people,

every time i see your cst plot i smile <gotproof>
Click to expand...

I guess it's better that a company make something that works and not know why it works than to make something that doesn't work and not know why. I don't mind doing the reverse engineering to show them how it works. The odd thing is that guy didn't even seem to know it worked.
 
i think herb possibly did know how it worked, CEBIK certainly knew ;)

Shockwave said:
I guess it's better that a company make something that works and not know why it works than to make something that doesn't work and not know why. I don't mind doing the reverse engineering to show them how it works. The odd thing is that guy didn't even seem to know it worked.
Click to expand...
 
The good news here is Herb is still alive and I have his contact information. He still lives within miles of the old Avanti factory.
 
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I wonder if Dale is now working for Sirio...or if Sirio changed the New Vector 4k from the original patent design, as they (Sirio) now lists the new vector 4k as a 3/4 wave jpole.
 
gamegetter said:
I wonder if Dale is now working for Sirio...or if Sirio changed the New Vector 4k from the original patent design, as they (Sirio) now lists the new vector 4k as a 3/4 wave jpole.
Click to expand...

Dale owns his own successful business today and is not connected with Sirio. From what I've been able to gather online, this guy is a sharp cookie. In other words I wouldn't consider his comments on the Sigma as a poor reflection on his overall knowledge. Remember, very little about the Sigma is apparent to most people unless you think outside the box and test it yourself. Examining the design or modeling it in EZNEC will gain you just about nothing. Opinions about this antenna mean little unless they are based on first hand experience.

Sirio changed the design after they modeled it in CST Microwave Studio. This program was able to show the radiation current and phase accurately and the new Sirio 3/4 wave design keeps the currents on the vertical in phase. The longer radials also improve gain. There is still some speculation as to if the 7/8 wave was better than the 3/4 wave. The difference is the top section of the antenna on the 3/4 wave is 1/2 wave while the 7/8 wave has 5/8 wavelength above the cone. My testing consistently shows improved coverage with the main radiator tuned to .82 wavelength.

PS: Sirio has been calling the Vector a "Coaxial J-Pole" for many years but never called it just a simple "J-Pole".
 
If one were to appeal to simplicity in terms of eye-balling the V4k and the J-pole, the first thing to greet the eye would be the J-pole has a 1/2 wave vertical and a 1/4 wave tuning stub beneath it - a gargantuan way to build a matching network, while the V4k does not.

Although there is a 1/4 wave section beneath the 1/2 wave vertical (based on which model you examine) on the V4k, it is immediately apparent that the V4k does not utilize the lower 1/4 wave section for a matching network, but uses a Gamma Match.

Logically, the next thought should follow being, "What then is this lower section about if not the matching stub?"

No more understanding of the antenna is necessary to have figured out it is quite apparently not a common J-pole.

It is wisdom to not believe everything you see, but it is abject stupidity to reject everything you see. Homer said that.
 
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It would be interesting to hear Dale's point of view, but that is not going to happen on this forum, and he has not posted on the other forum.
 
Shockwave said:
Dale owns his own successful business today and is not connected with Sirio. From what I've been able to gather online, this guy is a sharp cookie. In other words I wouldn't consider his comments on the Sigma as a poor reflection on his overall knowledge. Remember, very little about the Sigma is apparent to most people unless you think outside the box and test it yourself. Examining the design or modeling it in EZNEC will gain you just about nothing. Opinions about this antenna mean little unless they are based on first hand experience.

Sirio changed the design after they modeled it in CST Microwave Studio. This program was able to show the radiation current and phase accurately and the new Sirio 3/4 wave design keeps the currents on the vertical in phase. The longer radials also improve gain. There is still some speculation as to if the 7/8 wave was better than the 3/4 wave. The difference is the top section of the antenna on the 3/4 wave is 1/2 wave while the 7/8 wave has 5/8 wavelength above the cone. My testing consistently shows improved coverage with the main radiator tuned to .82 wavelength.

PS: Sirio has been calling the Vector a "Coaxial J-Pole" for many years but never called it just a simple "J-Pole".
Click to expand...

My testing consistently shows improved coverage with the main radiator tuned to .82 wavelength

Curious about that; Do you mean to say that literally or do you mean to say that you have modeled it?
 

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