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ASTROPLANE best vertical antenna ever?

Discussion in 'CB Antennas' started by nosepc, Oct 6, 2013.

  1. PD0G

    PD0G
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    I have a lot of files for MMana.
    Various lengths and material.
    Here an astroplane for 70cm

    upload_2017-10-14_22-2-16.png


    upload_2017-10-14_22-4-54.png


    upload_2017-10-14_22-6-3.png


    upload_2017-10-14_22-6-33.png







    Astoplane bij PD0G
    *
    433.0
    ***Wires***
    23
    0.0, -0.01, 0.0, 0.0, -0.025, -0.05, 0.0015, -1
    0.0, -0.01003, 0.10966, 0.0, 0.0, 0.10966, 0.0015, -1
    0.0, 0.0, 0.10966, 0.0, 0.01, 0.10966, 0.0015, -1
    0.0, -0.01, 0.11, 0.0, -0.01, 0.0, 0.0015, -1
    0.0, 0.02407, -0.05, -0.01, 0.02395, -0.05, 0.0015, -1
    0.0, 0.01, 0.10966, 0.0, 0.01, 0.0, 0.0015, -1
    0.0, 0.01, 0.0, 0.0, 0.02407, -0.05, 0.0015, -1
    0.0, 0.0, -0.3, 0.0, 0.0, 0.10966, 0.0015, -1
    0.01, 0.02407, -0.05, -0.01, 0.02395, -0.05, 0.0015, -1
    0.01, 0.024, -0.05, 0.024, 0.01, -0.05, 0.0015, -1
    0.024, 0.01, -0.05, 0.024, 0.0, -0.05, 0.0015, -1
    0.024, -0.01, -0.05, 0.01, -0.025, -0.05, 0.0015, -1
    0.01, -0.025, -0.05, 0.0, -0.025, -0.05, 0.0015, -1
    0.0, -0.025, -0.05, -0.01, -0.025, -0.05, 0.0015, -1
    -0.01, -0.025, -0.05, -0.026, -0.01, -0.05, 0.0015, -1
    -0.026, 0.01, -0.05, -0.026, 0.0, -0.05, 0.0015, -1
    -0.026, 0.01, -0.05, -0.01, 0.02395, -0.05, 0.0015, -1
    0.01, 0.0, 0.27, 0.01, 0.0, 0.0, 0.0015, -1
    0.01, 0.0, 0.0, 0.024, 0.0, -0.05, 0.0015, -1
    -0.026, 0.0, -0.05, -0.01, 0.0, 0.0, 0.0015, -1
    -0.01, 0.0, 0.0, -0.01, 0.0, 0.27, 0.0015, -1
    -0.026, 0.0, -0.05, -0.026, -0.01, -0.05, 0.0015, -1
    0.024, 0.0, -0.05, 0.024, -0.01, -0.05, 0.0015, -1
    ***Source***
    1, 0
    w8e, 0.0, 1.0
    ***Load***
    0, 1
    ***Segmentation***
    400, 40, 2.0, 2
    ***G/H/M/R/AzEl/X***
    2, 3.0, 4, 50.0, 120, 60, 0.0
    $$$Taper wire set$$$
    1
    -0.001, 0, 1.8, 0.015, 1.8, 0.0125, 99999.9, 0.01




    Upload a lot of photos.
    https://www.qrz.com/db/PD0G
    https://pd0g.wordpress.com/
     
    #241 PD0G, Oct 14, 2017
    Last edited: Oct 14, 2017
    JAF0 and Henry HPSD like this.

  2. The DB

    The DB
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    I was at a local scout camp. I don't have a setup to take with me on such a trip, yet. Even if I did, I was simply to busy this weekend to be able to set it up and use it. Doing something like that is on my list of things to do, so some day...

    I don't see the Sirio Top One as being the same antenna as the Astroplane, so I fail to see why these patterns would necessarily be the same, or even similar, outside of chance.

    The second model you show is taken right from the patent (for those that don't recognize it). I modified a model originally made by ghz24 to match Avanti's specs for the Astroplane. The only spec that I know is likely different from any modeling they have done is the mast length, as I used a mast length that modeling is saying is optimal instead of whatever mast length they used. However, their patent also says something interesting about said mast length.

    So changing the mast length can have an effect on the angle of radiation, which if true would also have an effect on the modeled pattern. I haven't looked at this possibility yet, but it might be another way to RF Steer the output into a desired direction. All of the mast length tests I have done were limited to being over an earth, so it is also a place to look to see if I can steer the antenna model's RF in the same way I can steer the Vector antenna model's RF.

    Do you have any models closer to HF, say 10/11/12 meters? The rest really aren't comparable to at least my models unless I work to adjust them.


    The DB
     
  3. JAF0

    JAF0
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    Was it anywhere near Camp Pahatsi?
     
  4. The DB

    The DB
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    I'm not in California, I was at Beaumont Scout Ranch southwest of St Louis.


    The DB
     
  5. bob85

    bob85
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    DB
    the old top-one was an astroplane clone,

    the new top-one is gamma matched & more like a fat bottom hat loaded dipole & nothing like an astroplane, but it has the same 4ft advantage in height of current maxima,

    somewhere on this forum there is a thread where i talked about the patent claiming that masts shorter than 1/4wave below the hoop caused radiation angle to rise,
    and reducing the radial flare causes radiation to be below the horizon,

    imho a 1/2wave mast gives the lowest mast currents,
    that's why i chose to isolate my astroplane 1/4wave below the hoop,

    There's also a thread dealing with the sigma4 radials & the patent claim of higher gain with wider radial flare,
    shockwave modified his vector with a larger hoop & shorter radials,

    i don't think you should shorten the radials.
     
  6. Marconi

    Marconi
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    Thanks for the clarification on the Old Top One compared to the New Top One Bob.
     
    #246 Marconi, Oct 20, 2017
    Last edited: Oct 20, 2017
  7. The DB

    The DB
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    I stand corrected. I couldn't find anything on it. All of the top one info that I could find was the version with the gamma.

    Yea, the patents talks about it said elements changing the angle of radiation, I quoted both sections above. When it comes to the radial flare and hoop size, modeling shows that it takes quite a bit to see a 1 degree change in said angle. When you have a 15 inch radius hoop and it takes adding or subtracting a foot or so change the radiation pattern by one degree... That being said, I only tried it with one mast length so far, and different mast lengths may have different results. when it comes to radial flare with modeling all I can say is need more testing. I was also mistaken about the mast length that I used, it wasn't optimal length like I thought it was. I had overridden that in the data for the model itself. This happened before I made said model, and I don't recall why I did that (or even doing it). The mast in that case was one wavelength long and not the optimal length that I claimed before. The result that I got would have been because of this. When I discovered that and corrected the model to have an optimal length mast the result was closer to Marconi's results.

    When I checked the angle of radiation based on mast length, very short lengths match what you said, the radiation angle lowered going to about 10 feet in length or so, then it gradually and steadily rose until it was about 25 degrees at about 25 feet (estimate). After that point the angle quickly dropped to negative angles, namely -6 degrees, and it stayed their from 30 to 40 feet where I stopped.

    As the negative angle was not the result that I expected with an optimal length mast, I asked Marconi to confirm it. Even though we use drastically different methods when it comes to modeling, our results tend to be pretty close to the same. It was after his results were noticeably different than mine that I started looking at my model and noticed my mast length was off.

    My modeling agrees with this, and I have shown this prior in this thread, however I was specifically looking to see if I could use mast length to change where the antennas RF would go, and to a somewhat limited extent I succeeded, but not the extent that I would have liked to have seen.

    When I made the models of the Vector in question I was just looking to see if such a thing were possible, and it clearly is. The problem with it that I noticed with the flared basket area was that impedance (R) would increase noticeably, and later when I started adding gamma matches to said antenna I found that at some point I could not get them to match, which with how gamma matches work makes sense. Even so, a wider basket on the Vector, to a point, does increase the gain on said antenna, and can actually come close to duplicating the old claim Shockwave made about said antenna, although some people no longer called said antenna model a "Vector", but these are off topic from said discussion. I had a very wide range of angles I could steer that antenna's RF, and not all of the steering was done by changing the ring diameter of the hoop on that antenna. Even keeping the ring diameter the same, by changing the length of the basket area and the length of the vertical element I could easily steer said antennas peak RF direction from over 30 degrees to under -10 degrees. With the AP models, and their claims of being able to change the antennas angle of radiation in the patent, I was simply seeing if I could do the same, and how far I could push said antennas design in this regard.


    The DB
     
  8. bob85

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    DB,

    its been a long time since we talked about the old top-one,
    im not sure other than me & Eddie who knows what he means when he says old top-one,

    the astroplane patent did lead me to think a significant change in angle was possible, they claim below the horizon which is usefull in some situations,

    what you are telling us about changing the vectors radial & monopole length steering the signal is the conclusion i came to after experimenting with my own & some friends vectors & sigma4's years ago,
    models did not agree with what i thought was happening when we made the adjustments so its interesting that you are able to do that in models.
     
  9. The DB

    The DB
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    Its not really that hard to understand what it is I am doing. For this I am simply using freespace as the environment because I want to see what direction the antenna is putting said signal before said signal interacts with an earth. It is nothing more complicated than that. It was actually Henry HPSD that told me how to do this back near when the Vector discussion ended, so it isn't even really my idea. He even provided an easily changeable vector model that I started playing with (and I later improved). I've known of this since early in that discussion when Henry and I discussed this, and I think I posted a few models showing this aspect of what he was talking about. At the time it seemed to go right over everyone else's head as no one outside of Henry and I, in a very post heavy time of the thread, even mentioned anything about it.


    The DB
     
    Henry HPSD and bob85 like this.
  10. nav2010

    nav2010
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    I see the AP as an hybrid. Electrically, it may resemble a J-pole or a sleeve type antenna but I think the top hat changes the angle of radiation by giving it directional gain. If you bent all the top hat legs upwards you would still have the same electrical length and it would still tune but I believe it would lose some gain. I think the top hat changes the angle of radiation by perhaps adding a small horizontal portion to the overall RF that is not cancelling or reactive against the rest of the signal. The way to prove this would be to take one of the top hat legs away and bend the other 3 legs to 120 degrees apart then add a horizontal band around the outside of the 3 legs. The inductance of the antenna will roughly be the same because of the missing leg. If i'm correct, the loop would cause the antenna to become ombni directional and you'd lose the horizontal effect and lose gain.
     
    #250 nav2010, Jan 7, 2018
    Last edited: Jan 7, 2018
  11. nav2010

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    Just to clarify what i've written, I believe each leg of the top hat reacts just the same way as a loop antenna does so that its reactance is the same so its like having 4 loops 90 degrees to one another.
     
  12. Marconi

    Marconi
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    Over time, I too had ideas how the A/P worked and whether it was a 1/4, 1/2, or 5/8 wave. I've changed my mind several times, but IMO it is just a simple center fed vertical 1/2 wave and has very little to no detectable horizontal RF radiating.

    My Eznec models below show very little difference in gain between the model with a horizontal Top Hat vs. the elements slanted up 45* degrees, with the edge going to the model that has the Top Hat slanted up.

    When I raised the Top Hat radials up the antenna went inductive and I had to shorten these radials close to 3" inches in order to restore resonance.

    I did not have the horizontal RF on in the setup, but the A/P models do not show hardly any horizontal RF. I use to think the same thing considering some testing I did with a buddy using his A/P vs. an A99 and a horizontal beam we both had up and working. I have tried this comparison over several times with other operators that had horizontal to work with...but was never able to get similar results. So, I've changed my mind about the A/P producing some horizontal RF. I think the Top Hat elements have out of phase currents flowing and IMO this causes cancellation.

    I guess this is your idea of trying Bob's spider plane idea with the Top Hat radials. I did not model your idea here, but I may try and see if the spider plane does anything for the model. I figure it will again make the model inductive and require an adjustment to shorten the radials...which will be difficult in my modeling with Eznec having to create a symmetrical loop for the top of the radials.

    DB, might have a handy solution with his 4Nec2 software. Maybe he could find some time to try the spider plane idea on his AstroPlane model.

    I would have to disagree here, because I see 3 top hat radials in place of 4 making an electrical difference that will surely make a physical length difference for these radials, but the difference may be small. I have a Starduster model with longer Top Hat radials and I will check this out.

    The models below show the antennas are very close to being fully omni directional, even with the top radiator being offset from the center about 3" inches or more. The patent says the top radiating elements for the AstroPlane can be set in line with the mast to make the antenna more symmetrical, and I have a model that suggest the original with offset does skew the pattern a bit...albeit very small.

    Are you planning to build and compare this idea? If so, I hope you will keep us posted.

    1. Below are two PDF file overlays of the patterns for the models . One with horizontal radials and one with radials slanted up at 45* degrees. The (*) on the upper left of the pages notes the gain and angle for the active model. There is very little difference in the gain and no difference in angle. However, the model with the slanted up elements shows a small advantage in gain.

    2. The top page shows the Free Space models that I started with. The bottom line shows the accuracy data results noted as the Average Gain Results. This value = 1 being the most accurate results. I also included here the performance results for the two models, one with horizontal and the other with slanted upward Top Hat radials.

    3. I also made a model that shows a real advantage in gain if you want to consider it in your ideas. The model has a full length 1/4 wave portion for the radiator in the top of the antenna. This is in place of the shortened one using a Top Hat. Again the (*) indicates the active antenna showing the maximum gain and angle for the full 1/2 wave model as an AstroPlane, and you will note a full dbi difference in gain for this full 1/2 wavelength model.

    I only included this one as an overlay showing all of the 3 patterns for these models.
     
    #252 Marconi, Jan 10, 2018
    Last edited: Jan 10, 2018
  13. Marconi

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    Here is the A/P model with a 1/4 wave extended radiator.
     

    Attached Files:

  14. nav2010

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    But adding a band horizontally joining all three legs electrically just like the basket band on a vector 4000 or lower half of a AP would add electrical length to each leg and even out inductance changes because of the missing leg. BUT...if each of the 4 legs on the AP has directional horizontal qualities, adding the band would neutralize any such pattern. Remember that not all loop antennae need to have a full electrical loop for them to act as a loop, they can form loop RF patterns with the inductive and capacitive relationship to the other half of the signal (in the case of the AP, the lower basket). This would be in the case of the AP, the reactance between the tips of the 4 top hat sections and the lower basket.
    Think of a 4 sided square directional loop fed at the bottom and the pattern it produces. If the reactance is equal all way around the antenna it will produce an hybrid RF pattern both H and V known as single linear polarization wave. I would add that normal loop antennae fed from the bottom produce a horizontal pattern seperated by an high impedance node and becomes a dipole. If you cut an inch from each side and electrically disconnected each side of the loop, hold it in place with fibreglass, equal the capacitance then it will still act as a loop providing the capacitance is equal and the reactance is equal on all sides.
    But the impedance will change when you do this because there is higher resistance at resonance at the gaps you've cut out.
    So in the case of the AP's top hat, the tips of the top hat are at high impedance in relation to forming a loop antenna with the basket but this does not mean that RF cannot form in that pattern, it just means it's more difficult to do so and the likelihood of it doing so is less possible. But....antennae are strange animals and if this particular beast see's a distinct opportunity of forming a loop then it will try, trying to form a loop but not doing it very well may just give it a tad of horizontal gain which is directional but who knows.
     
    #254 nav2010, Jan 10, 2018
    Last edited: Jan 10, 2018
  15. nav2010

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    Like thus
    [​IMG]
     

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