Nospec, the Patent was not done until 1970', so I'm not sure when the first hype came out about the Astroplane...including a lot of CBBS on the purpose for the idea and story why the AP only works low, or was designed to work low...like you suggest. Back then there was some FCC ideas about height in CB work, but I don't know anybody in the Houston, or SouthEast Texas area and the Gulf Coast that ever followed those rules...nobody. In the Valley with nothing but flat land from here to there, even 20' feet was not a big issue back in the 70's, but my Daddy always had a 100'-200' foot tower on his cotton farm and he had crews that worked his Field Services operations for several 100 miles up the I-35 and I-10 corridor
I find the antenna does work pretty well with a tip height no more than 20' feet high and for sure works better than a 5/8 wave with the tip at 20' and no more...with the 5/8 wave ground plane area buried about 3'-4' feet in the ground in order to try and keep the tip at or under 20' feet. Back in that time however most CB antennas that used a 1/4 wave radiator design or a 1/2 wave design were a little bit better off, in that regard, trying to work close to the Earth and stay within the 20' foot rule.
I guess Avanti's point was with a very short resonant 1/4 radiator on the top with a top hat to complete the 1/4 wave circuit...there was some advantage to be had with their design over the other designs.
Much like Coca Cola use to have cocaine as an minor ingredient, things change over time. It is alright now to come in out of the shadows of the old days, and put the AstroPlane up as high as you can get it, and see its performance shine, just like it did back in those days...if when guys followed the rules the A/P whipped all comers. The problem back then was I didn't know anybody that had a Starduster, Big Stick, or a HyGain CLR2, that didn't put those bigun's right up there on the top of the same pole they mounted their A/P on and there the old A/P took some what if a beating in the minds of CBr's anyway.
Do you, or have you any of these antennas, the old A/P, Top One, or the New Top One, and have you ever worked one? If not, I recommend any model will work just as good as any CB vertical out there...if you get the bottom of the antenna up as high to the mount. You might even see better signal reports at times from that little short radiator with a hat on top.
Thanks for the report. Have you got any pictures of you station?
Here are some images of my Top One with a full 1/4 wave radiator vs. New Top One. I also added a new project checking out a top hat radiator on my homemade Marconi 5x antenna just today. That Gain Master in the background is about 50' feet away, but my GM sees this antenna big time...I can see it on my meter. My Starduster is not show, but it is mounted about 6 feet lower and to the north, but it doesn't seem to effect the GM as best I can tell. My new GR 45 top radiator is fully top loaded, and that may make the difference even though it is only about 26' high while the bottom of the GM is 38.5' high.
BTW, in my real world testing here for the two A/P's I could see no difference in performance and the New Top One was mounted at the same height as the Old Top One...with the full 1/4 wave radiator. That said, the OTO was still higher by about 4'-5' feet. So, however we describe the New Top One...IMO it is every bit as good as the original A/P. Check my videos out in my signature below where I test some of my CB vertical antennas in a simple non-technical way.
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