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2 Element Quad Build

Discussion in 'CB Antennas' started by Redbeard U812, Oct 26, 2018.

  1. Redbeard U812

    Redbeard U812 Active Member

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    Looking to build a 2 element quad. Found a reference to a PDL 2 Avanti here on this site. Copied the Owners Manual, thanks to who ever posted it. Built my "StarBuster" based on the StarDuster, and it works great. Have been researching the 2 element quad for next build and the PDL 2 seems to have those interesting loops and a gamma match. Wanting to build my quad in horz. rectangle shape to keep from having to install a antenna matcher, 75 ohm coax, or a ballun to reach the 50 ohm desired for 10/11 meter use. Would the PDL 2 design be worth incorporating into my build? Would the gamma allow me to tune with out loss and maintain the square configuration? Does anyone know or can explain what advantage this gives to the quad?


     
    Shadetree Mechanic likes this.

  2. Redbeard U812

    Redbeard U812 Active Member

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    Thanks BJ,
    Have reviewed a lot of that already. The PDL 2 allows for 44" of beam. The configuration I have drawn calls for 8' of beam. Wondering if anyone has an explanation for the loops.
     
  3. midnight special

    midnight special Well-Known Member

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    pdl is a switchable horizonal/verticle beam,,,it was used with a switch box so as to be used either way,,,
     
  4. SIX-SHOOTER

    SIX-SHOOTER Well-Known Member

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    I prefer the Y-Quad design over the PDL II since it does not require the tubing loops. Both worked very well.

    SIX-SHOOTER
     
  5. Redbeard U812

    Redbeard U812 Active Member

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    Ok, now I understand. Should have gotten that out of the Owners Manual, I'm sure I was fascinated by the cool look of it and just skimmed through.
     
    midnight special likes this.
  6. JAF0

    JAF0 Active Member

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    When directly feeding a full wave loop or quad driven element, the typical expected impedance is about 100 ohms giving a 2:1 swr,
    but by adding a parasitic element about .2 wavelengths apart, the feed point impedance tends to drop close to 1.2:1.
    Trimming coax until an even lower swr is obtained is also sometimes employed mostly to keep the radio happy.

    Direct feed the bottom center and you will have a great performing horizontally polarized quad.
     
  7. midnight special

    midnight special Well-Known Member

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    in the 1977 the big dummies guide to cb radio has the best plans and ideas for a quad,, from a 4 element to making a 2 element....hard to find book i know but maybe some one has one to scan somewhere,,,,
     
  8. Slowmover

    Slowmover Well-Known Member

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    At Simonthewizrard came across the

    TGM COMMUNICATIONS

    QCB-1 Two Element Quad

    Advertised as an ultra-miniature CB Quad antenna. (See that Canadian website).

    And it jumped out at me. Hadn’t given any thought/research to this before. None, zero, nada.

    I’ve gotten way ahead of myself (still climbing towards “generally ignorant”), but have been thinking about a collapsible 33’ mast-mount on the rear of the travel trailer. That part I’m okay with.

    Antenna itself another question. 11-meter for now.

    I’m guessing that even when stowed down below roof height this may not be the “right” design type for the application. Bulky, etc.

    Leaving out vandalism, something which fits well inside the trailer width is the requirement for being parked. Available, but not erected (RV park lots aren’t large). Taken apart for travel? I come home (restoring an all aluminum trailer) about once monthly for a few days.

    Stock photo; similar, but not mine

    686DA6D1-34DF-4D13-9F07-B56272766476.jpeg

    Maybe someday a HI-Q PIRANHA will be applicable, but not for now.

    Below what looks like predecessor.

    858B53D0-184A-4188-82AB-69DCC0D04428.jpeg

    I’ve already decided to cover a skin puncture on the upper side near the port bow with a BREEDLOVE ball mount and 108”. That’s easy for me to remove and replace.

    But it’s not quite a “real” antenna per future plans. The mast with something atop is that future.

    Haven’t run across anyone using this design with an RV. Bad choice? Or seen as a matter of convenience (screwdriver, etc).

    .
     
    #9 Slowmover, Jan 17, 2019 at 11:59 AM
    Last edited: Jan 17, 2019 at 3:10 PM
  9. firerunner

    firerunner Active Member

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    For a 2 element antenna while on the road or camping you might look into a hexbeam. For a single band it can just be flat. I built a 6m hexbeam (11m would be bigger) and it can break down pretty small for transportation. Another is a moxon which I have built for 11m, great antenna and very wide banded only 4 arms vs 6 for hex. Same can be flat. cheap extendable fishing poles from ebay can be used.
     
    Slowmover, binrat and wavrider like this.
  10. firerunner

    firerunner Active Member

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    [​IMG]

    this isn't the finished hex but close, I found better fiberglass poles from tractor supply that fit the pvc pipe I used to holed in place but the orange driveway markers in picture work fine for this small 6 meter antenna .
     
  11. HomerBB

    HomerBB Sr. Member

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    I like the Moxon.
    I used to travel in a converted Greyhound bus RV. It was 40’ long. I rigged up a pole that extended to only 18’ and flew an A99 on it. I knew nothing about Moxons then or that might have happened, too. There are plenty of options for mounting the mast from attaching it to the ladder to rolling the tire of the RV over a base plate.
     
  12. Slowmover

    Slowmover Well-Known Member

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    Excellent. I didn’t expect to start reading about antennas, but there it was. I much appreciate the leads for further reading.

    EDIT: waiting all day for a load. Reading antenna threads is worse than going to the donut shop.
     
    #13 Slowmover, Jan 18, 2019 at 7:16 AM
    Last edited: Jan 18, 2019 at 10:45 PM
    undertaker likes this.

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