Thanks for the advice. Still kicking around my options. I've always been intrigued by this odd looking little antenna. I've been into CB since the early 70's and the buzz about the AP has never gone away as long as I can remember. I may just pick one up.
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Astroplane, what is it? 1/4, 1/2, 5/8 ??
- Thread starter Mark Scannura
- Start date
Thanks for the advice. Still kicking around my options. I've always been intrigued by this odd looking little antenna. I've been into CB since the early 70's and the buzz about the AP has never gone away as long as I can remember. I may just pick one up.
IMO, The DB gave you some sage advice.
Good ideas always seem to hang on in discussions. Why don't you try and find you a group that talks about stuff that interests you, instead of telling this bunch the subject makes you sick.
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Wow I did not know the results of your comparison Eddie I always thought the Avanti AP was superior to the Sirio Top One. Lol
Used to be an old guy here that ran one and it got out great. He had it up top his two story house and it worked as well as any other type of antenna around. Wasnt uncommon for him to talk up to 75 miles away up into Michigan on ssb with just a stock cobra 2000. When he passed a local guy got it and used it only up 30' mounted on the side of his house. He could talk all over on that darn thing .... 
Never said that now did i? As long as i have known you you and i have never really gotten along. And thats okay. Im not well liked by some and some think im great. Its fine. Im okay with it.....
DB and Marconi (long time no type Marconi hope all is well with you and yours),
do any of the models you guys have been doing on the AP design show the effects of using a straight 1/4 wavelength vertical piece instead of the top hat design?
I know what the patent sheet says about it, but i would love to know what your models show with regards to the take off angle.
also, do your models prove out that the current maxima is at the top of the antenna like the patent says.
I have always thought of it as an antenna that doesn't have a lossy matching network, can handle some real power because of that, radiates from the top, and can be safely mounted higher up because it wraps around the mast.
while i have been running an IMAX 2000 for the past few years, i plan on putting the AP back up sometime this year with the top somewhere around 50 feet.
i for one am glad this discussion has come back around because i have missed so much of it over the last few years.
LC
do any of the models you guys have been doing on the AP design show the effects of using a straight 1/4 wavelength vertical piece instead of the top hat design?
I know what the patent sheet says about it, but i would love to know what your models show with regards to the take off angle.
also, do your models prove out that the current maxima is at the top of the antenna like the patent says.
I have always thought of it as an antenna that doesn't have a lossy matching network, can handle some real power because of that, radiates from the top, and can be safely mounted higher up because it wraps around the mast.
while i have been running an IMAX 2000 for the past few years, i plan on putting the AP back up sometime this year with the top somewhere around 50 feet.
i for one am glad this discussion has come back around because i have missed so much of it over the last few years.
LC
Hey LC, below are three models of my AstroPlane.
1. is the overlays for the 3 models to compare.
2. is the original A/P set to the same tip height of the model with a full 1/4 wave radiator.
3. is the original A/P with the top hat set at 36' feet that I started with.
4. is the A/P with an 89.1996" x 0.625" inches for a full 1/4 wave radiator on top.
When I built my Old Top One with a full 1/4 wave on top my radiator I ended up using 87.5" inches of radiator made up of 2 x 48" x 0.625" sections connected together with 3 hose clamps and about 4" inches of overlap on each of the two tubes.
My on-the-air comparison results between my Old Top One and my New Top One, with results all averaged-out, between the top hat and the full 1/4 wave showed me no difference that I could detect with a couple of weeks taking RX signal reports from about 8 regular buddies all around me from 25 - 60 miles out.
Hope this helps bud.
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i need to get used to interpreting these antenna models, but it looks to me like the 89" vertical example reduced some high angle radiation, but also raised the angle of the maximum signal a slight bit.
did i get that right?
also, how did you arrive at 89"?
here is the part of the patent sheet that has always intrigued me with regard to take-off angle:
"It has been found, however, that the flare affects not only the impedance, but also influences the takeoff angle at maximum signal strength."
to me, this says that playing with the flare at the bottom will raise or lower the take off angle.
another quote:
" When the flare was omitted and the conductors 16 and 18 were tested parallel to the first conductor 14 it was found that the takeoff angle at maximum signal strength was as much as to below the horizontal."
so that would mean that reducing the flare (smaller diameter hoop) can aim the take off angle lower on the horizon.
have you ever played with that aspect in your models?
I realize it would also change the impedance, but have no idea to what degree and therefore what the optimum hoop diameter might be for an astroplane purposed for long distance DX contacts.
thanks for the charts, i will look more at them so that i will understand your responses better.
LC
did i get that right?
also, how did you arrive at 89"?
here is the part of the patent sheet that has always intrigued me with regard to take-off angle:
"It has been found, however, that the flare affects not only the impedance, but also influences the takeoff angle at maximum signal strength."
to me, this says that playing with the flare at the bottom will raise or lower the take off angle.
another quote:
" When the flare was omitted and the conductors 16 and 18 were tested parallel to the first conductor 14 it was found that the takeoff angle at maximum signal strength was as much as to below the horizontal."
so that would mean that reducing the flare (smaller diameter hoop) can aim the take off angle lower on the horizon.
have you ever played with that aspect in your models?
I realize it would also change the impedance, but have no idea to what degree and therefore what the optimum hoop diameter might be for an astroplane purposed for long distance DX contacts.
thanks for the charts, i will look more at them so that i will understand your responses better.
LC
I mostly try to do models to specs, but I do mess around with ideas presented to me. The problem I run into is trying to explain what I see.
I have been told that the bow in the radials has something to do with the match and possibly the angle, but if it was me building the A/P for sale back in the days and I knew some particular setup would produce the best gain at the lowest angle and also show a good match...that is what I would be building and selling.
For years what I typically heard in CB was chatter about some technical report that claimed an inexplicable difference...due to some design mode or doing this and that to our setups.
Where I saw such reports that looked 1/2 way legit to me, I often found the differences noted and well documented...might be supporting the claims, albeit the differences measured were typically far less than the CB stories suggested. Much of it reminded me of the "Old Fish Story" or CB BS, that we've all heard before.
This is basically why I got into modeling...so maybe I could test some of these ideas. I just didn't realize how difficult it would be trying to explain the results
It would be better if folks would ask specific questions...rather than me posting lots of words trying to explain...all-the-while folks eyes glaze over and say O'Boy.
On the other hand, folks may have a question about a specfic model and more often than not, can't give me a reference to the model, thinking surely I can remember.
LC, it not that I don't want to try...it is just a tough thing to do...and then when it might be days later...stuff just falls thru the cracks.
Sometimes this works better in private conversations, and then at some point in understanding...we can always take the conversation to the whole forum.
Look this stuff over and ask me if you have questions.
I have been told that the bow in the radials has something to do with the match and possibly the angle, but if it was me building the A/P for sale back in the days and I knew some particular setup would produce the best gain at the lowest angle and also show a good match...that is what I would be building and selling.
For years what I typically heard in CB was chatter about some technical report that claimed an inexplicable difference...due to some design mode or doing this and that to our setups.
Where I saw such reports that looked 1/2 way legit to me, I often found the differences noted and well documented...might be supporting the claims, albeit the differences measured were typically far less than the CB stories suggested. Much of it reminded me of the "Old Fish Story" or CB BS, that we've all heard before.
This is basically why I got into modeling...so maybe I could test some of these ideas. I just didn't realize how difficult it would be trying to explain the results
It would be better if folks would ask specific questions...rather than me posting lots of words trying to explain...all-the-while folks eyes glaze over and say O'Boy.
On the other hand, folks may have a question about a specfic model and more often than not, can't give me a reference to the model, thinking surely I can remember.
LC, it not that I don't want to try...it is just a tough thing to do...and then when it might be days later...stuff just falls thru the cracks.
Sometimes this works better in private conversations, and then at some point in understanding...we can always take the conversation to the whole forum.
Look this stuff over and ask me if you have questions.
There must be something about this antenna. I've been into CB since the early 70s and the buzz about how good or better the AP performs compared to other alleged better antennas is almost universal. It is an endless debate in almost any radio forum you can find. It was a debate on the CB radio back then and in radio magazines before the internet. You can hardly find anyone who says it performed less than what they replaced it with when it came to signal strength distance communication. I think, and I emphasize "think" from what I have been reading all over the web, is it may very well be that Avanti really found something unique with this design that enabled what seems to be a 1/4 wave physical antenna to perform more like a 5/8 wave. And I think that was their logic to say it was a 5/8 wave. To make 5/8 wave a "Claim" for advertising, they set out in an interesting & unique way to measure it physically as way to back up the 5/8 claim. Am I correct on this point at least in theory on what Avanti tried to do?
I'm not technical enough on antenna's/radiation patterns to really understand all the science and theory. I'm trying to learn but my learning path is typically from the top down not the bottom up in a technical area since I'm not an engineer/tech. So I so get lost in the science here. If I can get the top view, its helps me understand the science/theory aspects faster. Thanks for everyone's input.
Thanks Mark
I'm not technical enough on antenna's/radiation patterns to really understand all the science and theory. I'm trying to learn but my learning path is typically from the top down not the bottom up in a technical area since I'm not an engineer/tech. So I so get lost in the science here. If I can get the top view, its helps me understand the science/theory aspects faster. Thanks for everyone's input.
Thanks Mark
For what it's worth, Sirio USA (in California) shows to have two of the Top One antennas in stock.
https://www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=186
https://www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=186
His version appears to be much more substantial in both structure and price.
I thank everyone for the comments. In the note above my friend loosecannon, missed me joining in at the time. At that time, I was in and out of the hospital