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shortened yagi

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by YL3JD, Jun 17, 2021.

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  1. YL3JD

    YL3JD Ham Member QRZ Page

    Dr OM's

    I'm want to build a shortened 3 el yagi for 20 meters.
    What would be the preferebale way to make the lenght of the reflector and director?
    Calculate and build the driven element like a shortend dipole with coils, measure the lenght and add or substract 5% percent for the reflector and director?

    73 hanz yl3jd
     
  2. KK4NSF

    KK4NSF Ham Member QRZ Page

    in theory, you could use 6 ham-sticks.... with the center two being tuned to resonance, the rear two adjusted to 5% long, and the front two adjusted 5% short. For spacing, you might have to experiment.... but good place to start is use full size yagi spacing. All you'd have to build is the boom, and matching section.
     
  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    Isn't the typical Tri-bander (20/15/10m) a shortened Yagi for 20m? Shortened by the residual inductance of the 15/10m traps.
     
  4. YL3JD

    YL3JD Ham Member QRZ Page

    Thanks, that would mean that the reflector and the director also are loaded.
    i could load the directory and refelector in "my" yagi also.
    hanz
     
  5. YL3JD

    YL3JD Ham Member QRZ Page

    Thanks yes that could be but the longest element still can be 8 meters and i want to have the longest element about 5,5 meters.

    hanz


     
  6. K7MEM

    K7MEM Ham Member QRZ Page

    No, that wouldn't work. When you shorten a driven element with coils, you need to do the same thing to the reflector and director. Shorten then with coils. I didn't find a lot of information on 3-element shortened yagisfor 20 Meter. But there seems to be a lot of information on 2-element shortened yagis for 20 Meters. Below are a few links. All of them appear to be working with widths of about 5 Meters and boom lengths around 2.5 Meters. You might then experiment with adding another element.

    Two Element 20-Meter Beam

    An Overview of Small Loaded Yagis

    The KJ5VW 20 Meter Mini Yagi
     
  7. N4UFO

    N4UFO Ham Member QRZ Page

    Coils and cap hats seem to work... I have owned two of these style beams, both 2 and three element:

    Mq-2-2.jpg
    MQ-36SRhr.jpg
    These beams are roughly the size of a 6m yagi with coils and cap hats on the end of each element. He makes some with three bands (20-15-10) and some with 5 bands (20-17-15-12-10). There is a wire bus that goes around the coils that the base of each connects to. If you just want 20m, no bus needed. He also makes a version without the 'enhanced' reflector. More info here: http://www.tgmcom.com/
     
  8. YL3JD

    YL3JD Ham Member QRZ Page

    thank you indeed not much on shortened yagis. thanks for the reply and the url's.

    73 hanz
     
  9. YL3JD

    YL3JD Ham Member QRZ Page


    thank you very nice antennas and the dimensions are perfect !
    thaks for the url i will get into that.

    73 hanz
     

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