5/8ths Quad?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KB6LEE, Jul 21, 2021.

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  1. EA1DDO

    EA1DDO Ham Member QRZ Page

    I have just built a 8 elements Quad (for 144 MHz) a couple of weeks ago, just for fun.
    Home designed, home built, with bamboo spreaders (I found then in a gardening store).
    It is performing quite good. Very happy.

    upload_2021-7-21_17-50-52.png

    73, Maximo
     
    WE4E, WZ7U, K6CLS and 1 other person like this.
  2. RW4HFN

    RW4HFN Ham Member QRZ Page

    Good compared to WHAT? After all, this is, in fact, a vertical stack of two Yagi with a NON-OPTIMAL inter-storey distance... The stack of two Yagi is definitely better in all respects.

    In general, it is much more practical to use tube antennas for VHF, combining the functions of a conductor and mechanics... Wire beams, IMHO, this is for HF. From poverty...
     
  3. K8JD

    K8JD Ham Member QRZ Page

    I seem to recall the "Cubical Quad" with best compromize of Gain and F/B used a Director in front of the driven loop !
     
  4. KB6LEE

    KB6LEE Ham Member QRZ Page

    W1VT may have the closest to an answer to my question, though WA7ARK adds a good point about the parasitic elements. (Is that a Cessna 185?)

    The rest of the discussion is way above my current pay grade, but talk amongst yourselves as it is all good reading. Thanks for the responses!
     
  5. KB6LEE

    KB6LEE Ham Member QRZ Page

    K8JD, your response came in while I was reading the others, but the Quad design I saw was based on a reflector. I'm open to supporting theory, though.
     
  6. EA1DDO

    EA1DDO Ham Member QRZ Page

    Hi Igor, I am not comparing the antenna, just saying that it is doing the job. I have created in NEC simulator from scratch, optimized, then built. Shows low SWR and according tomy log and pskreporter, it is doing the job.


    Absolutely.
    And a stack of two quads will be better, less than 3dB better. Four quads will be even better,... but I am nto talking about total gain.

    You are right, but this antenna is for fun, not a permanent antenna.
    Bamboo spreaders were $1 a bag of 20, center spiders $2, boom was here already, wire too. Total cost for me $3.
    If I would go for aluminium tube.... final cost would be much higher, same performance, and much less fun.

    73, Maximo
     
    RW4HFN likes this.
  7. RW4HFN

    RW4HFN Ham Member QRZ Page

    Sorry, Maximo! It seemed to me that you did not quite understand my message...

    I meant that a single square, in its essence, is two connected dipoles with curved ends... At the same time, the gain is lost due to the curved ends and the interstory in 1\4 lambda.
     
    Last edited: Jul 22, 2021
  8. EA1DDO

    EA1DDO Ham Member QRZ Page

    Igor, Have you ever compared a Yagi with a Quad?
    Same boom lenght, same place, same height.

    When you have the chance, build and compare yoursekf for example this 4el with any optimized Yagi.

    There is something in the quad that simulation programs does not take into account, but is real. You need to feel it yourself.

    73, Maximo
     
  9. RW4HFN

    RW4HFN Ham Member QRZ Page

    I don't believe in devilry... If there is time , I will illustrate it with models.

    I firmly believe in the expediency of using WIRE squares only on HF. No more than three elements. Two is better. Which, in fact, has become widespread in HAMs practice.
     
  10. EA1DDO

    EA1DDO Ham Member QRZ Page

    Models are not good here.
    We need side by side real antennas.
     

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