“Magic antenna” radiation pattern as MMANA sees it - FYI

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by AA7EJ, Oct 23, 2013.

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  1. AA7EJ

    AA7EJ Ham Member QRZ Page

    http://vk1od.net/antenna/W5GI/ calls it "collinear" and "he knows what he is talking about" per K4SAV.

    But if is not, what is it?

    Three allegedly phased dipoles in-line are what?
    Just for a record, not for meaningless argument

    73 Vaclav
  2. G3TXQ

    G3TXQ Ham Member QRZ Page

    VK1OD doesn't call it collinear! Try reading his article again - particularly the first section under "conclusions".

    What is it? Three half-waves out of phase!

    Steve G3TXQ
  3. AA7EJ

    AA7EJ Ham Member QRZ Page

    Steve, you are absolutely correct, accept my apology, please.
    Here is a copy from the article.

    "W5GI acknowledges an article by W2OZH as inspiration for the W5GI Mystery Antenna, and describes it The W5GI Multi-band Mystery Antenna is a fundamentally a collinear antenna comprising three half waves in-phase on 20 meters with a half-wave 20 meter line transformer. He goes on to claim that the antenna covers 80 to 6 meters with low feed point impedance and will work with most radios, with or without an antenna tuner."
  4. G3TXQ

    G3TXQ Ham Member QRZ Page

    Accepted ;)

    VK1OD shows that, on 20m the currents are not in phase in the three half-wave sections as they would need to be for it to be a collinear. The result is a 6-lobe azimuth pattern (as opposed to 2 narrow lobes of a collinear) and a quite different feedpoint impedance.

    So, we have three 20m half waves with out of phase currents, fed at the centre through a half-wave ladderline section .......... doesn't that sound like a G5RV?

    Steve G3TXQ
  5. AA7EJ

    AA7EJ Ham Member QRZ Page

    That would be disrespectful to Louis Varney .
    I think "Mystery antenna” name is fitting, but personally I would drop the “antenna” part.
    73 Vaclav
  6. K2WH

    K2WH Premium Subscriber QRZ Page

    The G5RV, is a garbage antenna in its own right. A simple single wire dipole is a better performer when fed with ladder line and a tuner.

  7. AA7EJ

    AA7EJ Ham Member QRZ Page

    this thread was an attempt to inform , hence "FYI" it title, about "Mystery antenna".
    It is not about G5RV.
    G5RV was mentioned because other article compared the "Mystery antenna" to it, simple as that.
    If you would like to discuss G5RV please do so in another thread. Thread hijacking is not nice.

    And as far as feeding "simple single wire dipole with ladder line and tuner" - if that is what works for you, fine. However,as general as your statement is and assuming that "simple ...dipole" refers to single band usage - it is almost 100% incorrect.

    73 Vaclav
  8. W5DXP

    W5DXP Ham Member QRZ Page

    What would one call a "simple single wire 102 ft dipole fed with 30 ft of ladder-line and tuner"?:)
  9. AA7EJ

    AA7EJ Ham Member QRZ Page

    Item 1 simple single wire 102 ft dipole = an antenna designed to operate on 204 ft wavelength
    Item 2 30 ft of ladder-line = cannot be used to build a name, insufficient data
    Item 3 tuner = irrelevant and insufficient due to item2

    ...sorry Dave , can't do that...

    73 Vaclav
  10. W7WRX

    W7WRX Ham Member QRZ Page

    Oh no.. Not more links to vk1od again.
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