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diy full wave 11 meter loop antenna question

Discussion in 'Home Brew' started by Mudduckmobile, Sep 29, 2016.

  1. Robb

    Robb Yup

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    Are you using that 20m loop on 10m and 11m?
    Or are the two different loops?



    Because if one loop was used for all those bands; then I kinda figured that you were using a 4:1 balun and 450 ohm feeder with a tuner.

    Thanks!
     

  2. Mudduckmobile

    Mudduckmobile Well-Known Member

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    Question:
    Can I put a PL 259 on ladder line to connect my yaesu ft450d to a 11 meter loop antenna, do I really need to use coax?
    Just a crazy question...'cause I don't know.
     
  3. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    ROBB if you want multi band the delta loop use the lowest band , IE 20 meter loop will work on 17,15,12,11,10 etc with tuner.
    I DO NOT use tuner I build mono band coax fed, friend of mine uses his delta multiband and has good results.

    4:1 or 1:1 what ever you have laying around the shack,, would do the trick
     
    Robb likes this.
  4. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    Use a short piece of coax, around 10 feet or less in length to get the coax outside the shack, then use a balun to connect the coax to the ladderline, ladderline to the delta, have fun
     
  5. Mudduckmobile

    Mudduckmobile Well-Known Member

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    Cool, will do. Thank you.
     
  6. cbphreaker

    cbphreaker Ganbatte Kudasai "Success depends your effort"

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    If you use 50 ohms unbalanced into a 4:1 balun you'll end up at 200 Ohms balanced "on the other side. 450/200 = 2.25. So you'll have a line with an swr 2.25. While this swr isnt that bad for ladder line you can get an easy transformation to 450 by using a 1/4 wave length of 300 ohm twin lead right after the 4:1 balun "into" the 450.

    If you are building a mono band antenna, you can use a 1/4 wavelength of 450 ohm balanced in parallel with the input at your antenna which will go from 450 to 100 and since the loop is a balanced antenna it's perfect. No silly right hand scews on the radiation pattern and practically 0 common mode current on the line.


    Or you could get a 9:1 balun (50x9 = 450) either would work acceptably.

    Cheers

    CBPheaker
     
    #21 cbphreaker, Oct 3, 2016
    Last edited: Oct 3, 2016
  7. Mudduckmobile

    Mudduckmobile Well-Known Member

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    Thank You for your help! It seems like no one use's the loop antenna around here, To me it looks like it is a very good antenna, for what goes in to it. I also like the way it could Lead to a nice quad beam some time down the road.
     
  8. cbphreaker

    cbphreaker Ganbatte Kudasai "Success depends your effort"

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    You will be happy with the performance of the loop once you get the line issues straightened out.

    You already have the right idea with the 450 Ohm balanced line. I always wondered why more CB operators don't use this stuff. The loss per hundred feet is around 4 times less than LMR400 and cheaper too.

    If your the DIY type you can make a 4:1 balun from coax which costs almost nothing, at it's output connect the 1/4 wave length 300 twin lead to the 450. Measure the length of the 450 to be a multiple of a 1/2 wave on 11meters and parallel 1/4 for a perfect match to your quad.

    Its possible to do the same thing at the other end if you wanted to use 450 ohm line for a long, low-loss run. Simply use another 1/4 wave length of 300 ohm and input that in to another 4:1 coaxial to get back to 50ohms unbalanced at the antenna end.

    This setup requires no tuner, is mono banded, tuned, very low loss, and helps in suppression of RFI.

    I hope you get it working, you will never want to use coax again!

    Cheers

    CBPhreaker
     
  9. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    222DBFL likes this.
  10. Mudduckmobile

    Mudduckmobile Well-Known Member

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    Ok, I cant find the answer to this question, maybe my search skills suck...So I will ask.
    With the "full wave delta loop wire antenna" cut so center of band is set at 27.385.00
    where else would this antenna work? I think I saw something about odd numbers...
    !! meters....etc verses even 10,20 etc.
    Or you know of a good page(s) to read to learn?
    And I am trying to find a Fiber Glass push up pole 30ft. or longer to hold the delta loop.
    I find shorter, and I find carbon Fiber but do not want that.
     
  11. tecnicoloco

    tecnicoloco Tweaknician in Training

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  12. Mudduckmobile

    Mudduckmobile Well-Known Member

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    My friend, your link has opened a new can of worms :)
    The SATURN looks fun to try next, after the delta loop is done!
    Now I need to find the Fiber Glass rod.
    Thank you!
    73
     
    tecnicoloco likes this.
  13. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    Driveway markers( fiber glass rods) available at home depot, or use 1/2" pvc for spreaders.
     
    Mudduckmobile likes this.
  14. Mudduckmobile

    Mudduckmobile Well-Known Member

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  15. Road Squawker

    Road Squawker Sr. Member

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    Perhaps because CBers only use a small slice of the RF spectrum with mono-band antennas,................................ and seem to think that the VSWR MUST be 1.0:1.
     

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