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Re: Vertical spacing of wires in 5-el hexbeam

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  • Steve
    Roy, I had a similar (but not so acute) problem and decided to sacrifice 12m; but that is very much a personal decision. 30 inches sounds very tight indeed. If
    Message 1 of 4 , Jul 1, 2007
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      Roy,

      I had a similar (but not so acute) problem and decided to sacrifice
      12m; but that is very much a personal decision.

      30 inches sounds very tight indeed. If you're using Leo's construction
      method is there any chance you could use longer "poles" on the
      baseplate to push the spreaders out further?

      If you do decide to try to cram in the 5 bands, a couple of things you
      should remember:

      1) Achieving vertical separation at the centre post is more important
      than at the ends - because that's where the highest currents flow.

      2) Try to utilise the total height available in a way that band
      separations are proportional to wavelength i.e. don't use it all up
      on the 20m/17m gap at the cost of making other band elements too close.

      73,
      Steve G3TXQ
    • roycarlson12
      Thanks to K4KIO Leo for his help. The simple answer is my spreaders are 5-6 inches too short. They need to be at least 120 inches (as is clearly stated on
      Message 2 of 4 , Jul 1, 2007
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        Thanks to K4KIO Leo for his help. The simple answer is my spreaders
        are 5-6 inches too short. They need to be at least 120 inches (as is
        clearly stated on Leo's website). The moral is all 13' crappie poles
        are not created equal!

        In answer to my original question I think I'll forge ahead and create
        a 3-band version for now. I expected to rebuild this antenna at
        least a few more times, for example next time using an aluminum
        baseplate instead of kitchen cutting board, so I'll learn from this
        one and do it better the next time around.

        Roy AC0FN

        --- In hex-beam@yahoogroups.com, "roycarlson12" <rcarlson_ac0fn@...>
        wrote:
        >
        > I'm building my first hexbeam following the instructions on K4KIO's
        > website.
        >
        > I have a minor problem in that my spreaders (13' crappie poles with
        > the last section removed) are a little short. When my 20m elements
        > are horizontal and placed as far as possible out on the spreaders,
        at
        > the mast end they are only 30-31 inches above the baseplate instead
        > of the recommended 38 inches.
        >
        > At this point I have the 20 and 17m wires roughed in with zip ties
        > and it appears that if I want to keep the wires horizontal I'll
        have
        > to leave out the 10m and possibly 12m elements due to the lack of
        > vertical space on the mast.
        >
        > My question is should I bring the elements up to a higher point on
        > the mast resulting in wires that are not horizontal, or should I
        > scale this back to only 3 bands? I am leaning towards a 3-band
        > version given the solar cycle what it is today.
        >
        > Thanks - Roy AC0FN
        >
      • Woody
        You could probably use the 15 foot crappie poles instead of the 13 foot and also make the center post a little taller. W3HII, Woody
        Message 3 of 4 , Jul 3, 2007
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          You could probably use the 15 foot crappie poles instead of the 13 foot
          and also make the center post a little taller.

          W3HII, Woody
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