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h.brew cubical quad,2,3 or 4 element w/pics

Discussion in 'CB Antennas' started by johnny9, Jan 20, 2014.

  1. johnny9

    johnny9 Active Member

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    well i finally started a couple of the sections for the quad i decided to build.

    figured id post the build process,and also say this is my very first antenna build.
    why a quad..well,i have a buddy"ham" that has a sweet antenna farm.
    he has a maco 5/8 wave,super penetrator,2 element cubical thats vertical and one thats horizontal..onl 2 elements and talks worldwide whenever he wants to usually.
    so i decided since im somewhat of a welder to make a fully adjustable quad as far as changing the spacing and spreaders very easy.
    today this is what ive come up with so far..the cross sections fit precisley over the beam i will be using and so far just made these 2.
    still trying to decide if i want to stay with 2,but i think 3 is a good number to start with.
    the driven,the reflector and 1 director,,maybe add another director to have a 4 element but have not decided just yet..any comments are welcome,j9
    btw,im talking just fine with the 70,s astro plane and pres grant moble in the house..just wanted to better my receive a little and learn something in the process.
    so ar this is very light weight and strong.the copper wire is heavyer than the 2 cross sections for sure.
    the x on the sections are;
    5/8x .062 6063 alum tube
    1/2x.062 same tube with 2 screws holding the 5/8 together and have adjustment if needed.
    3 ft x 3/8 fiberglass rods"for electric fences"from tractor supply 1.99 each.
    slotted the 1/2 tube for hose clamp and the fiberglass rods,will add screw when finished.
    40 ft of copper 12 ga wire for the drive element
    gonna use 14ga for the reflector and directors when time comes.may switch to all 14 ga as it is lighter and my buddy said he sees no difference in the 12 and 14ga wire on the antennas in his opinion.


     

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    3 people like this.

  2. hotrod

    hotrod Well-Known Member

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    looks good so far. a quad from everything ive read issupposed to be best beam
    style to run. probly why your bud does good.
     
  3. johnny9

    johnny9 Active Member

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    his work great for sure and there 2 element with 14ga wire and been in use for 7yrs iirc..and hidden in the trees lol.he says for me to use a"7ft 8 1/2 inches of rg11" piece of coax from the driver to keep it down to 50 ohms..says if i use the rg8 up top it will be 100 or more ohms,and the rg11 will bring it down to 50 omhs .
    im learning a lot thankfully.
    he likes my design on the arms the way they slip over the boom and easy to add more and adjustable easy,so i will be making him a few soon im sure..
    and all his work fine with a radio shack 75.00 tv rotor(y)
    thats my plan also on the cheap rotor if i cant get the 25 yr old one i have working..

    byw this is where im getting my measurments.and learning.
    The Ultimate Guide to 11 Meter CB Antennas
     
  4. PyroZuki

    PyroZuki New Member

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    This looks like it will be good. I'm looking forward to more progress.

    Pyro
     
  5. vkrules

    vkrules Sr. Member

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    Are you sure about the 75 ohm matching section. Would be ok on a 2 element quad but a 4 element should be closer to 50 ohm , impedance varies with no of elements, spacing and tuning.
     
  6. Captain Kilowatt

    Captain Kilowatt Professional Amateur
    Staff Member

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    The nice thing about quads is that the gain varies very little with reasonable element spacing. It is quite easy to adjust element spacing to obtain a nice 50 ohm feedpoint impedance without sacrificing much gain.
     
    2 people like this.
  7. johnny9

    johnny9 Active Member

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    sorry ive been slacking and have been fixing other things..then got to thinking how the quad would be lighter with the poles from a crappy pole,i have a couple and the frist 2 sections are very strong and light.
    but im gonna go ahead with the rods i have..i will try to get the wire strung this weekend if the wife dont keep me busy..
     
  8. Jay in the Mojave

    Jay in the Mojave Active Member

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    Hello Jonney9: Good going, your parts look good.

    What type of matching circuit are ya going to use, or do I just need to tune more often?

    Good luck.

    Jay in the Mojave
     
  9. johnny9

    johnny9 Active Member

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    jay,we have talked before..couple times past week but couldnt get ya today if that was you..i heard with the kids in the background calling you lol..
    if your who i think you def have the best audio ever heard and sound like your in a recording studio ..;) def the best of all the flowers my radio has ever received..

    my matching system that has worked for the guy that got me going on this antenna is plain and simple.
    7ft 8 1/2 inches of rg11 for the driver element hooked to rg8 coax..im learning and only no what the guy down the road uses and he talks the world over also..you talk to him also.. 967 west fl j9

    always open to opinions also;)
     
  10. HomerBB

    HomerBB Sr. Member

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    RG11 jumper is too long @ 8' 7-1/2"

    RG11 has .75 velocity factor.

    Assuming 27.205 for CB center of band as the frequency to tune for, the length of 1/4 wavelength would be 108.5".

    This must be adjusted for the Velocity Factor of the RG11, which is .75.

    108.5 x .75 = 81.375" or 81-3/8"

    in feet that is 6.78125' or 6' 9-3/8"
     
  11. GnG8d

    GnG8d Well-Known Member

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    I was thinking that too but the game was starting and didn't take the time to look at it, but 27.185 is the center of the band if you want to split hairs.

    Personally, I'd make it 50ohm and skip the 75ohm matching section.
     
  12. johnny9

    johnny9 Active Member

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    i think i remember my buddy saying he did the first one yrs ago at 50 ohm and it just wasnt cutting it he said..i will run what you guys said by him as well as im not even in the game of this stuff yet..but the fab part is all me..
    working on 2 boats and still been puting this off..maybe this week i will get something done..

    359 i have to ask..love the 4 elem quad in your avatar..wondering if youve had a 2 and 3 element before and if the 4th really does much more then the 3 ?
    j9
     
  13. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    I think the RG11 Velocity Factor is closer to 66%.
     
  14. HomerBB

    HomerBB Sr. Member

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    I don't want to split hairs, but I think nearly two feet of coax length is a rather big hair.
     
    1 person likes this.
  15. GnG8d

    GnG8d Well-Known Member

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    LOL, I don't either, 27.2 is an easier number to work with.
     

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