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Stacked 3 element yagi's ?

Discussion in 'CB Antennas' started by Jay in the Mojave, Dec 12, 2004.

  1. Jay in the Mojave

    Jay in the Mojave Active Member

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    Hello Bud73:



    Stacking the Yagi beams for VHF MURs should not be a difficult thing to since the beams are not large and heavy as HF Beams are.



    Cushcraft stacks their 2 meter beams at 116 inches. See



    www.cushcraft.com/support/pdf/951411.pdf



    And here are a few more web sites that have stacking info.



    www.vhfman.freeuk.com/rad...cking.html

    www.astronwireless.com/stacking.html

    www.grantronics.com.au/docs/StkYagis.pdf



    www.ifwtech.co.uk/g3sek/s...cking2.htm



    Jay in the Mojave <img src=http://users.joplin.com/dutch64804/posticon44.gif ALT=":44">



    www.a1antennas.com


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  2. Jay in the Mojave

    Jay in the Mojave Active Member

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    Hello Bud73:



    Ok good deal. Yeah that would be a good call letting us know what happens there. We are all ears.



    Jay in the Mojave



    www.a1antennas.com <img src=http://users.joplin.com/dutch64804/posticon44.gif ALT=":44">


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  3. Jay in the Mojave

    Jay in the Mojave Active Member

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    Hello Bud73:



    Here is a web site for the Cushcraft 4 element 2 meter broad band yagi. It shows at the bottom of the page Figure 5 the Stacking arrangement for there 4 element beam. Model 124WB Boomer.



    www.cushcraft.com/amateur...anuals.htm



    Third one down.



    The neat thing about this is that I am sure you can buy the Stacking Kit, Phasing/Stacking Coax Harness and Aluminum Tubing and mounts, from Cushcraft. If you don't want to make it yourself.



    Now if you want to experiment around a little you can build the phasing coax to have the antenna feed 180 degrees out of phase (phase a fancy 50 cent word for time). Just add in a 1/2 wavelength in coax after figuring in the velocity factory, for one of the stacked beam antennas.



    This will only allow the same gain as one yagi beam antenna but will have a razor sharp null in the center forward direction. This is great for Direction Finding, or being able to talk to other stations while interfering stations are nulled out, Neat-O!



    Jay in the Great Mojave Desert <img src=http://users.joplin.com/dutch64804/posticon44.gif ALT=":44">


    </p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=jayinthemojave>Jay in the Mojave</A> at: 12/19/04 8:12 am
     
  4. Bub73

    Bub73 Member

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    Stacked 3 element yagi's at MURS freq's 151.820 -154.600.

    How do I figure the proper boom spacing for maximum gain?



    Thanks

    Bub73


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  5. Jay in the Mojave

    Jay in the Mojave Active Member

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    Hello Bud73:



    Ok good deal, looks good.



    I can't tell if the mast is made from PVC Plastic or metal pipe. Suggest the coax be run inside the metal pipes. I think it will all fit with the Tee inside the plumbing Tee, and coaxes to the antenna running thru the Horizontal pipes.



    If the beams are using a Gamma Match, the coax will be radiating some energy distorting the beams pattern.

    This would slightly cut down on the coax radiating energy off the outer shield, from the Gamma Match's



    Jay in the Mojave



    www.a1antennas.com <img src=http://users.joplin.com/dutch64804/posticon44.gif ALT=":44">


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