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full wave antenna

Discussion in 'CB Antennas' started by Robalo, May 5, 2008.

  1. Robalo

    Robalo
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    [​IMG]
    [​IMG]


     

  2. SR385

    SR385
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    Looks like a circular 'quad'. 5 elements, on what band?

    Should have pretty decent gain.
     
  3. Captain Kilowatt

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    It is a five element "quad" with horizontal polarisation. Ideally the circular elements are the best performers because the shape occupies the greatest area.
     
  4. KingCobra_CDX882

    KingCobra_CDX882
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    Got to disagree wit you on this QRN

    Horizontal is likely best for DX
    better low angle (typically)
    also goes further(typically) before being refracted on first hop

    Circular on the other hand
    is more resistant to fade
    and therefore is easier for other party to listen longer to one who is talking circular

    Advantages to both
    but Horizontal wins out

    Except if both the receiving and transmitting signal is circular
    only then does circular win out

    because most people use either vertical or horizontal
    circular losses 1.5 Db typically to the listening station
    (not always very bad thing though)
     
  5. Beetle

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    A circular antenna does not produce "circular polarization". The driven element appears to be fed at the bottom; hence, horizontal polarization.

    Like on a traditional quad. Fed at the bottom (or the top) center, it's horizontally polarized. Fed at the middle of either side, it's vertical.

    A "cubical" quad doesn't produce cubical polarization, and a circular loop antenna, whether parallel to the ground or sticking up in the air doesn't produce "circular" polarization.
     
  6. W5LZ

    W5LZ
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    ... and unless there's a particular reason for that circular polarization, there's absolutely no benifit from using it. So what's that 'particular reason'? How about high physical speed of one of the transmitters? That's about it. In this particular instance, high speed don't mean over 70 mph, or 90 mph, or 150 mph. :)
    - 'Doc
     
  7. Robalo

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    lol I enjoyed this conversation, i'll put up more pictures as soon as I buy one. The person that constructed these makes them from 2 to 8 elements. His fundamental theories are supposedly the greatest, so lets try one if the city permits it in my yard at least just to test it.




    [​IMG]
     
    #7 Robalo, May 6, 2008
    Last edited: May 11, 2008
  8. Porkchop454

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    looks cool anyway
     
  9. KI4MSJ

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    looks like the moonraker but with round wire instead of straight from element to element
     
  10. Captain Kilowatt

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    I missed this. Oh well better late than never. I meant circular elements as in "round" not as it pertains to polarity. As for what polarity is best for DX'ing well that depends on a lot of things between tyhe two statiions. I used to run a Wilson Shooting Star and had the feedlines phased to provide verticle,horizontal,left-hand circular, and right-hand circular at the flick of a switch. Sometimes the same polarity worked best and sometimes the opposite polarity worked best. When signals bounce off the ionosphere and the earth they bear no resemblance to the original polarity when they are finally received.

    BTW losses in a circular polarity system versus a linear system (V or H) amount to 3 dB not 1.5dB.
     
  11. AE5RD

    AE5RD
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    Does the guy that makes these antennas have a website? It looks like a good project
     
  12. hookedon6

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    There's a small advantage to round (circular) loops at much higher frequencies That is, rain droplets cannot hang off the lower corners when it rains and detune the antenna. With circular elements, there are no corners, and the rain just rolls off.

    For the polarization it will be the same, feed it at top or bottom and you will have horizontal. On the side and you'll have vertical

    also you won't get as many birds sitting on a round antenna as compared to a yagi. my antenna is not above my patio for a reason
     
  13. Lazybones1222

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    what band it that one for?
     
  14. Robalo

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    cb 27.205
     
  15. W5LZ

    W5LZ
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    And 'circular polarization' aside, since it isn't circularly polarized anyway... :)

    Looks like a nice 5 element quad. The elements are sort of large, but if you can support the weight of them, ought'a do as well as any other 5 element quad. Any benefit to the circular elements rather than rectangular ones? Sort of, but not a huge difference at HF. Mechanical benefits? Maybe, but I sort of doubt it, kind'a. The conductors are large enough that I think water/ice wouldn't deform them like smaller wire, but I'd hope the spreaders are strong enough to carry the additional weight of the probable water/ice load. Sure different though.
    - 'Doc
     

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