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Quad feeds

Discussion in 'Amateur Radio Antennas' started by Mudfoot, Jul 5, 2019.

  1. Mudfoot

    Mudfoot Sr. Member

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    For a single band quad, what types of feeds are best. Do different feed techniques give better bandwidth, nulls, rejection.... Crap like that?

    Just wondering if I should build my own.


     
    Shadetree Mechanic likes this.

  2. BJ radionut

    BJ radionut Supporting Member and 6m addict

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  3. Flatop

    Flatop New Member

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    I use a two element quad on 11m and have fed it with a quarter wave 75ohm matching stub and a choke. I find it works quite well, the bandwidth is a little narrow because of the stub, but this may be of advantage too. Impedance is 56ohms at the centre frequency, around 60 at either end of the band. I have no other data to compare though.
     
  4. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    Mudfoot and Shadetree Mechanic like this.
  5. Flatop

    Flatop New Member

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    I agree with the four, but since I am feeding about 100ohms, quarter wave stub suits of coarse. With the 1:1 balun, I know that this is technically correct, however due to power handling/heat dissipation for my situation, I think the choke that I use comes out on top at the possible sacrifice of minor pattern distortion.
     
    Shadetree Mechanic and Mudfoot like this.
  6. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    #6 Shadetree Mechanic, Jul 12, 2019
    Last edited: Jul 12, 2019
  7. Dr_DX

    Dr_DX Active Member

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    Quote from earlier post:

    Lightning Antenna's Quads use the same matching system that SE called the
    SFS FEED SYSTEM. It allows the SWR adjustment close to the point where the
    antenna mounts to the mast.
    It consist of flexible wires (not coaxes) running along the boom and also brass rod stubs,
    which are included with our set of wires. The SFS System allows the use of much more
    power than a Gamma Match and results in very low SWR over all forty channels.

    Take a look at the Patent here:

    Patente US4236160 - Loop driven element antenna system and voltage feed system - Google Patentes

    SFS provides two independent feed points, one pure vertical
    polarization, the other purely horizontal. Two coaxial lines
    then run to the operating position as usual and are selected by
    the operator through a coax switch. (Neither the antenna switch
    nor these coaxial lines are included with the antenna.)

    In a nut shell the antenna is voltage fed and NOT current
    fed like a traditional quad. That what allows this
    antenna to be dual polarity.

    I hope this answer your questions.

    Thank You for interest in our antennas.
    George.

    Lightning Antennas
    Manufactured in CA by INNOVA
    Tecate, CA 95117
    (408) 625-7717 Phone
    (408) 457-9440 Fax
    george@lightningantennas.com
     

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