Hello
I have a question that i noticed in the original patent for the Avanti Astroplane.
On Page 6 under section 10 which i highlighted in blue it talks about efficiency.
My question for those who understand the details about how antenna theory is
By removing the top hat does that make antenna work better as long as the SWR
stays in range. Also for my use i do not stray above or below 1-40?
I am curious as this is out of my area of knowledge.
The attach file is the PDF of the patent for the Astroplane and Astrobeam.
This is especially so when the conductor 46 is one-quarter wavelength, for the efficiency drops somewhat for a broader band when the conductor 46 is capacitively loaded, as by the crossed conductors 48 and 50.
I run one and it’s great .. I bought it NOS I put it together as marked and it talks thinking about put 7/16 din on tho or direct fedI would love to try one of Coily's Astro Planes out one day to see how they perform.
Thank you very much for the explanation! I have run this original Avanti Astroplane for the last 8 years. I bought it new and for me it has worked amazingly. I was looking for the patent for the Astrobeam hoping to find enoughThis is the specific text he has highlighted.
When you add a capacity hat to a 1/4 wavelength antenna element, efficiency goes down. This is a form of loading and all forms of loading have this effect. But this is also that "less efficient" statement that so many people get hung up on, when nothing is said about how much less efficient. As is almost always the case when this phrase is invoked, in the real world it isn't so much that you will notice the difference so I wouldn't worry about it.
The Astrobeam came with a straight upper element, and there was a version of the Astroplane that also came with a straight upper element as well, although not as many of those were sold. I have also heard from others who have changed out the cap hat for a straight element as well, so it has been done.
I wouldn't worry about it if your just staying on the regular 40 channels. The CB band is a very narrow band, and very few antennas struggle to have enough bandwidth for it, and when they do there is typically a reason for it. The Astroplane design should have plenty of bandwidth with or without the cap hat.
The DB
This is the specific text he has highlighted.
When you add a capacity hat to a 1/4 wavelength antenna element, efficiency goes down. This is a form of loading and all forms of loading have this effect. But this is also that "less efficient" statement that so many people get hung up on, when nothing is said about how much less efficient. As is almost always the case when this phrase is invoked, in the real world it isn't so much that you will notice the difference so I wouldn't worry about it.
The Astrobeam came with a straight upper element, and there was a version of the Astroplane that also came with a straight upper element as well, although not as many of those were sold. I have also heard from others who have changed out the cap hat for a straight element as well, so it has been done.
I wouldn't worry about it if your just staying on the regular 40 channels. The CB band is a very narrow band, and very few antennas struggle to have enough bandwidth for it, and when they do there is typically a reason for it. The Astroplane design should have plenty of bandwidth with or without the cap hat.
I remember the Big Stick. Everyone had them back in the day. Seemed to be the Antron 99 of the 70s and 80s.I talked to a guy in NY today who was transmitting on really old Shakespeare big stick and it was making the trip really well.
Like o'l @Crawdad said, old junk to some but in this case it's was working well.
Different folks Different strokes
Radio Shack actually sold the original Shakespeare Big Stick back in the late 1970s and early 1980s. This was long before they had Archer make their junk blue copy of the antenna, with the "100 watt fuse" in the base. I've seen bigger toroids in a 300 to 75 ohm TV antenna transformer.I remember the Big Stick. Everyone had them back in the day. Seemed to be the Antron 99 of the 70s and 80s.