ASTROPLANE best vertical antenna ever?

[loosecannon]

glad to hear you're ok Marconi.

I didn't mean to fan any flames with my post, I just wanted Jack to get himself caught up and then explain his position instead of making you repeat yourself.

definitely take it easy and thank goodness you can't catch COVID over the radio!

Maybe disinfect your mics LOL
LC

 

[Marconi]

Thanks LC. You did good.

 

[hotrod]

glad to see ya back..hope ya feeling better

 

[Marconi]

Well, I am getting stronger every day. Not so much overwhelming fatigue and confusion in thinking. Short term memory went first.

The morning of the 2nd day in the Hospital, after test an a medical plan was set...I got 3 transfusions...similar to what President Trump explained. 4 hours later I felt much better, but from day to day for 5 more days...I was on a roll-coaster from good to delusional, and could not do a thing for myself.

For safety of staff and my self, I laid in bed in my own mess sometimes, and if I moved wrong, like a leg over the edge of the bed...alarms would go off in the room. I was like a prisoner without bars.

God has always blessed me. I don't exactly understand why, but I'm thankful to be back doing my thing with my friends on WWDX.com and my family.

I have lots of other health problems, diabetes for 40 years, COPD, and A-Fib. I have several very good DR's that have kept me going for all my 83 years...much while in bad health.

 

[freecell]

First things first, nosepc was a troll. I doubt he actually put up an antenna made out of iron, or had the know how to actually make such an antenna.

And when it comes to metals used to make antennas, this really is irrelevant. You said you can use EZ-Nec? Why don't you try modeling the same antenna with different metals in it and see for yourself.

Some comparison models of an antenna made out of various metals and tuned to resonance with each... This was done in 4nec2.

[photo=medium]6462[/photo]

As we can see, the different metals don't make all that much difference when it comes to gain and angle. Seriously, stainless steel, about as bad of a metal commonly used to make antennas, has a loss of 0.07 dB compared to a perfect conductor. Good luck noticing that difference.

And here are the structure losses from the different metals.

• Perfect conductor, 0%
• Copper, 0.27%
• Aluminum, 0.33%
• Stainless Steel, 0.71%

Seriously, Stainless Steel, the worst metal commonly used to make antennas has a structure loss in this case of less than 1%? Again, gook luck noticing that difference...

There is a very good reason there is such a small difference in performance between these antennas. Most of the RF doesn't actually travel through the metal itself, but the space around said metal. If all of the RF traveled inside of the metal, we wouldn't have to worry about things like velocity factor, or said velocity factor would be specifically determined by the metal used, and not the dielectric material used in said coax.


The DB

https://rudys.typepad.com/files/qex-nov-dec-2k-antenna-wire-conductors.pdf

 

[Marconi]

Very high tech, but a good resource.

 

[Red Bull]

For shits and giggles I put up my A/P about 25 ft. not near high enough.

 

[Marconi]

Looks like a Maco V-Quad close by.

I ran my Old Top One (A/P knockoff) at close to 50' feet and it worked any of the big antennas I had.

 

[Red Bull]

The A/P does pretty good for 25ft. My main Maco 5/8 gp received some major damage from hurricane ZETA when it passed over n ga some weeks back. I can still talk on it and the swrs are still low but the rx/tx is not as good. The A/P hold it's own with the damaged Maco.

It's an original A/P from the 80's all weathered but still has flat standing waves!

 

[nfsus]

I've now built 2 different styles of astroplane as well as owning an original. The 2 I've built are different in design however neither have hats. Both have flat swr readings. Bother are now sitting 9ft between the ground and the hoop. One has a small hoop with the radials straight up to the cross bracket. The other has a 30in hoop and the offset radials like factory. So far 9ft off the ground I've had good results with a difference of 1 to 2 s units from other stations that I talk to daily.

According to what I've read the hat changes electrical length and the radiation focal point. Does it make a difference in function if you eliminate the hat and make the element longer? What about the size of the hoop? I've read that controls the toa.

Think think think. So many opinions.

I have no analyzer but one should be here within the next 2 weeks.

 

[freecell]

"What about the size of the hoop? I've read that controls the toa."

No, it doesn't.

the length of element 14 controls the elevation, radiation or takeoff angle and determines the electrical wavelength at which the antenna operates.

 

[The DB]

Does it make a difference in function if you eliminate the hat and make the element longer?

If you remove the cap hat and lengthen the vertical element to compensate, you will have essentially if not the same radiation pattern. The feed point impedance will also change to some extent, so bear that in mind.

What about the size of the hoop? I've read that controls the toa.

The patent talks about this. You can change the antenna's angle of radiation with this method, but only in one direction, up. So if you need to make the "take off angle" higher, you make the basket support legs shorter, and the ring slightly bigger to compensate. The patent also states that the antenna was designed to have optimized this "take off angle" for CB use, and doesn't say anything about lowering the "take off angle".

Two paragraphs later the patent also talks about this type of change affecting the feed point impedance of the antenna, so be warned about this should you decide to try this.

I should also note that it talks about this angle being blow the horizontal, or below the horizon, which suggests the information the patent is talking about when it comes to "take off angle" is specifically in free space. If an earth is present, there is no angle below the horizontal (or horizon) when referring to the "take off angle", so I feel this should be mentioned.

In the past, I was able to confirm that you can in fact change the antenna's angle of radiation in free space with this method, however, when an earth, any earth, was present below the antenna the modeling software did not show any change in the "take off angel" of the antenna no matter what I did with it, short of changing how high it was mounted above said earth.




The DB

 

[nfsus]

Until my analyzer gets here I'm stuck questioning and guessing. Thanks for the reply. I'm seeing stronger tx reports. Up to 2 s units. However the rx is also a heavy 1 to 1.5 s unit noisier and or louder over the factory astro? So I'm going in the right direction I think. I've also added a small cap hat on the extended element. So it's now a longer element and has a small 16" hat. Cant tell the hat did anything. Flat swr across all 40 ch. So it's all just guesswork at the moment

 

[freecell]

from the patent:

"a mast (element #14) having a length below level "B" of about one quarter wavelength, i.e., about the length of the conductors 16, 18 gave an optimum takeoff angle." patent # 3587109, page 5, lines 8, 9 and 10.

the takeoff angle @ maximum directivity shown in figure #7 of the patent is @ 5 degrees above the horizon. accordingly the takeoff angle is optimum when the radiating mast (element #14) is between 16 - 18 feet in length, taking into consideration the large diameter to length ratio of element #14, required to be 1.75 inches in diameter to fill out and fit snugly in the u-bolt located at level "A."

if your mast (element #14) extends to 9 feet below the loop @ level "B" (to ground) connecting both sides of the quarter wave matching stub your current configuration is within the optimized conditions mentioned in the patent. if you choose to increase the elevation you will need to either use some form of non-conducting support structure or you will have to electrically isolate the bottom of the mast (element #14) if mounted on any galvanically conductive support structure to preserve the current level of performance while in pursuit of an improved line-of-sight conducive to long distance ground wave communications. you're off to a good start!

 

[nfsus]

from the patent:

"a mast (element #14) having a length below level "B" of about one quarter wavelength, i.e., about the length of the conductors 16, 18 gave an optimum takeoff angle." patent # 3587109, page 5, lines 8, 9 and 10.

the takeoff angle @ maximum directivity shown in figure #7 of the patent is @ 5 degrees above the horizon. accordingly the takeoff angle is optimum when the radiating mast (element #14) is between 16 - 18 feet in length, taking into consideration the large diameter to length ratio of element #14, required to be 1.75 inches in diameter to fill out and fit snugly in the u-bolt located at level "A."

if your mast (element #14) extends to 9 feet below the loop @ level "B" (to ground) connecting both sides of the quarter wave matching stub your current configuration is within the optimized conditions mentioned in the patent. if you choose to increase the elevation you will need to either use some form of non-conducting support structure or you will have to electrically isolate the bottom of the mast (element #14) if mounted on any galvanically conductive support structure to preserve the current level of performance while in pursuit of an improved line-of-sight conducive to long distance ground wave communications. you're off to a good start!

So anything beyond the 9ft below the hoop needs to be isolated? I suppose this is where the undesired currents begin to build? And if so, what is the true effects of this?