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Antenna Project Success!

Discussion in 'Home Brew' started by T23, Nov 17, 2010.

  1. T23 making your first antenna can be an adventure , but most succeed . the hardest part is trying . 2 problems i see is that 1 i think the 5 ft all-thread is going to be the vertical/hot/radiator pard of the antenna and it is way way too short for the CB band . you need something closer to 108 -112 inches so you can tune it . 2 you also need something much larger than a 5 dt diameter metal disk for a ground plane . 1/4 wave length antennas really really need 1/4 wavelength ground elements . 1/4 wavelength on the cb band is about 9 ft .



    im not able to visualize your parts list into an antenna .
    if you could post some pics it would help a lot ;)
     

  2. T23

    T23 Active Member

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    Heres the pics I promised...




    T23
     

    Attached Files:

  3. T23

    T23 Active Member

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    The 102' is the copper wire thats inside the pipe, the ground plane is 5 inches not 5 feet, and the all-thread is is also about 5 inches, the copper wire is the antenna...not the all-thread.


    T23
     
  4. i cant tell in the pic , but the 102 inch wire does not make contact with the 5 inch ground plane ... correct ?

    what i would do to make that work is add 3 or 4 108 inch wires from the 5 inch ring you have there and have them spread out like slices in a pie and use a nail or stone or brick to to hold them in place . then check your vswr . you will probally need to add a few inches of wire to the 102 to get it to tune . you should be able to get to 1.3 or lower .
     
  5. T23

    T23 Active Member

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    Yes. correct the 102' wire does not make ANY contact at all with the disk. It has two rubber washers insulation it from the all-thread. Should these wires you mentioned adding be sloped or can the be level with the disk/groundplane? And what difference exactly will making the wire 108' instead of 102' make? I thought it was supposed to be 102' not 108' right now I have it at 105' for slack for tuning.

    Any suggestions on how to attach the wire to the disk?

    T23
     
  6. Robb

    Robb Yup

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    The radials should be 102 inches long at a 45 degree downward slope and attached to your ground plane disc.
    BootyMon's description is as accurate as the one I had built when I first got into radio - BTW.
     
  7. Robb

    Robb Yup

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    Drill four hole equally spaced along the edge of the ground plane disc, and then attach the four 102 in wires to these holes. You can screw them in place to keep the connection solid. Hold down the ends with bricks or rocks; just keep the fairly taut and spaced evenly apart. You can use soft stranded wire to do this, so that should make it much easier to accomplish.
     
  8. mackmobile43

    mackmobile43 Jock Supporter

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    Robb your idea about the urethane is good and if one where to add another section of smaller diameter tubing inside the larger one then the rigidity would be greatly increased.

    399 can sit back and learn a thing or 4 about engineering.
     
  9. HomerBB

    HomerBB Sr. Member

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    Now, getting the subject back on track, this is the 1/4 wave groundplane I recently put together. It's very similar to Booty's :

    [​IMG]

    The four radials were pulled taut by the flex of the PVC pipe. The vertical comprised of a length of SS cable pushed up into a hollow fiberglass fishing pole. The yellow part you see is a fiberglass post hole digger handle used to bring the various parts together. It is/was one of the finest antennas I've brewed both for its simplicity to build and its impressive performance in its class.

    BTW, enjoy all the help you get here. Read everything you can, and find the greater consensus on a given topic. Start there and then take it to where you find the best results. That shows your willingness to learn, your ability to be guided, your initiative to work it out, and your capacity to grow.

    A wise man listens to every opinion, and a wiser man does not accept them all. :)

    Keep it up. It is just gratifying to work it out.
     

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