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Base Have a look at this Antenna

Discussion in 'CB Antennas' started by AudioShockwav, Jan 15, 2020.

  1. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    I use to make a similar claim that the A/P was a 5/8 wave. I've changed my mind though and now believe it is a very effective vertical 1/2 wave.



    I made the taller model to see if I could scale it to 22' feet, and see how it worked. I ended up with it near 14' instead of the stock 11' feet. The 22' foot idea did pretty much as you suggested and I was no able to get it to match. I stopped fiddling with it, because I did not get an answer to my email to Tagra. Some folks just don't like questions!

    My comment about brexit was in jest. Corruption is ubiquitous in our World.

    Do you hear any local comments about the BT-101?
     
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  2. bob85

    bob85 Supporting Member

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    Nobody local talks about bt-101 or astroplanes,
    i am the only person i know of in the area that has owned an astroplane style antenna, two other guys near me had them in the 70's but both are silent key,

    most locals know what im using, some call it "that upside down basket thingy"

    i agree on effectively what the astroplane is,
    it may have 5/8wave of tube plus a hat that replaces 4ft of radiator,
    when you fold it into 1/4wave flared transmission-lines like that you end up with something that is like a hat loaded 1/2wave dipole with some skewing to the pattern, its a bit lob sided like a j-pole,
     
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  3. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    Bob85, I have an Avanti report with some numbers, and some Internet exhibits that claims Avanti professionally tested their A/P.

    I also have documents that support what they claimed, who did the tests, and how it was done. i just studied it and tried to follow the idea. So, this is what the models will hope to show.

    I scaled them to 144 Mhz. IMO they support much of what is claimed. Again, I just used the information from the testing report to make these models using the same 27 MHz A/P model I posted earlier in this thread.

    I will post this and the modles in a new thread...so others can check this out and it won't be buried in this thread.

    I'm going to call the tread "The AstroPlane - Another View Point."

    Here is Avanti's report and the ad I found in CB Magazine. I found the Technology News report sometime back...while searching Google for the Engineer's name that Avanti used to do their research. I may have posted these items already.

    Also note, in the early part of this report there is talk about the PDL and another CB antenna being created at this same time.

    Sorry for the poor copies. Try using the PDF print or the Zoom functions to help improve the images.
     

    Attached Files:

    #33 Marconi, Jan 24, 2020
    Last edited: Jan 24, 2020
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  4. bob85

    bob85 Supporting Member

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    not seen that before Eddie, interesting story,

    they have it wrong about where 1/2 & 5/8waves radiate from so the illustration is misleading people into thinking the astroplane has a big advantage in getting over obstructions,
    in reality it has 4ft or so advantage over a straight radiator 1/4 1/2 or 5/8 at the same FCC legal tip height & less than that if the groundplane is hat loaded,

    4ft sounds like not a lot but its worth having when your antenna is in the situation illustrated in the avanti advertising or even lower below the roof line,

    i am also unsure if they are trying to tell us that the astroplanes folded design decouples it from mast & feed-line ( which is false )

    or are they saying that the mast must be isolated at some distance below the hoop to minimise cmc & preserve the pattern which i believe to be true.
     
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  5. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    I didn't post this information with an idea the details were right.

    At best the models show me the error they made in getting the high gain they report as 4.46 decibles over isotropic radiator (their words).
     
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  6. bob85

    bob85 Supporting Member

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    i think we have a fair understanding of which parts of the advertsing are true & which are sales bluster,
    the story of how the astroplane came about sounds reasonable to me, lou martino is the guy that had his name on the pdl & astroplane patents.
     
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  7. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    We can't forget to mention Herbert R. Blase.
     
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  8. bob85

    bob85 Supporting Member

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    Herb was the sigma4 (y) & saturn horizontal omni guy,
    don't some of the patents have both lou & herb's name on them.
     
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  9. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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  10. HomerBB

    HomerBB Sr. Member

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    @Marconi & @bob85
    Did you fellow notice in the patent application for the original AP that it was said that changing the length of the "conducting mast" below the ring would change the TOA of the maximum gain, and that it is possible to create downward tilt to below horizon as the mast is lengthened? Interesting...

    http://www.google.com/patents/US3587109

    I think this could account for a variety of reported experiences with this antenna.
     
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  11. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    Homer, I don't recall this specifically in the patent, but this has often been claimed as steering. I could have easily missed something, but I would think a few members here would have set me straight on this issue in a hurry.

    The patent has 2 columns and each line is numbered. Maybe you could post the location with column and line numbers. That will help me narrow down what it is that you've noted.

    I'm sure I've posted about this before, and I probably did models to help me show what I was seeing.
     
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  12. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    Homer, the link at the bottom is a link to a thread discussing steering.

    The posts noted below are specific comments about steering in the long thread at the bottom. These comments will give you a sample of the discussions I mentioned in my earlier post #41 above. Maybe you won't have to read the whole thread...if you find words in these posts on the issue about steering.

    You were right, there are comments about the steering ideas in the patent, the guys here talk about it. However, there were no references given. I don't mind reading it over, but I would have to hope I found the words you mentioned.

    ASTROPLANE best vertical antenna ever?
     
    #42 Marconi, Jan 26, 2020
    Last edited: Jan 26, 2020
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  13. M0GVZ

    M0GVZ Sr. Member

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    That alone would be enough for me to avoid this antenna like the plague. It clearly has serious common mode issues, insufficient RF ground and unless you have the ability to model the installation to figure out the best length of mast it'll be entirely down to luck whether it either ends up being the best DX antenna you've ever had or no better than a dummy load.
     
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  14. HomerBB

    HomerBB Sr. Member

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    Thanks, Marconi.
    @M0GVZ.
    I understand your response, however, CMC has never been an issue for me. I just do the CST (common sense thing) and isolate my mast 1/4 wavelength below the ring, and use a CMC choke in the coax at the same location.
    There are great reason to have such steering capabilities in a design such as getting a signal out of a hole, or into a lower elevation, etc.
    One of the best CB antennas I've ever had the pleasure of flying.
     
  15. Redbeard U812

    Redbeard U812 WDX-1030 / U812 South Texas

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    Gotta like that CST (y)
     
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