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Re: HB in vicinity of 80 meter Horizontal loop??

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  • Steve
    Trent, I tried modelling something like you describe. I had a 20m hexbeam at 30ft. I placed the corner of a horizontal 80m full-wave loop 10ft away. The loop
    Message 1 of 4 , Feb 1, 2011
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      Trent,

      I tried modelling something like you describe. I had a 20m hexbeam at 30ft. I placed the corner of a horizontal 80m full-wave loop 10ft away. The loop tilted from a height of 12ft nearest to the hex and 20ft furthest away.

      The presence of the loop degraded the hex radiation pattern severely when the hex was pointing in the direction of the loop. The effect was a lot less - but still quite significant - when the hex was pointing away from the loop or at right angles to it. Probably not surprising as the loop is resonant and acts as a parasitic element on all odd and even harmonics.

      I guess that's not what you wanted to hear! I don't know how you are feeding the loop, but there may be some way of making it non-resonant when not in use by the way you terminate the feedline.

      73,
      Steve G3TXQ

      --- In hex-beam@yahoogroups.com, "trentkj4kaf" <trentkj4kaf@...> wrote:
      >
      > This afternoon I was able to do lots of measuring and layout work for my new hex beam location. The best I can come up with puts it within 5 or 10 feet of my 80 meter loop. This is the lower portion of my loop that is about 12 or 15 feet. The Hexbeam will be at 30+ feet. Any thoughts about how this may be an issue?
      >
      > Thank You, Trent KJ4KAF
      >
    • trentkj4kaf
      Steve, You are right, I hate to hear it. I feed the loop with about 50 feet of 450 ohm ladder line. When I am not using the loop, I Break the 450 ohm ladder
      Message 2 of 4 , Feb 1, 2011
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        Steve, You are right, I hate to hear it. I feed the loop with about 50 feet of 450 ohm ladder line. When I am not using the loop, I Break the 450 ohm ladder line about midway and connect both loop conductors to ground. Let me know if you have any more thoughts on this. Measuring the performance of my HB will be tough, as it is my first one.

        Thanks again, Trent KJ4KAF

        --- In hex-beam@yahoogroups.com, "Steve" <steve@...> wrote:
        >
        > Trent,
        >
        > I tried modelling something like you describe. I had a 20m hexbeam at 30ft. I placed the corner of a horizontal 80m full-wave loop 10ft away. The loop tilted from a height of 12ft nearest to the hex and 20ft furthest away.
        >
        > The presence of the loop degraded the hex radiation pattern severely when the hex was pointing in the direction of the loop. The effect was a lot less - but still quite significant - when the hex was pointing away from the loop or at right angles to it. Probably not surprising as the loop is resonant and acts as a parasitic element on all odd and even harmonics.
        >
        > I guess that's not what you wanted to hear! I don't know how you are feeding the loop, but there may be some way of making it non-resonant when not in use by the way you terminate the feedline.
        >
        > 73,
        > Steve G3TXQ
        >
        > --- In hex-beam@yahoogroups.com, "trentkj4kaf" <trentkj4kaf@> wrote:
        > >
        > > This afternoon I was able to do lots of measuring and layout work for my new hex beam location. The best I can come up with puts it within 5 or 10 feet of my 80 meter loop. This is the lower portion of my loop that is about 12 or 15 feet. The Hexbeam will be at 30+ feet. Any thoughts about how this may be an issue?
        > >
        > > Thank You, Trent KJ4KAF
        > >
        >
      • sailingto
        Doggoneit Steve, I had not even considered the effects of my 80 meter loop to my hexbeam. My hex is located only 15 ft or so from the corner of my 80 meter
        Message 3 of 4 , Feb 3, 2011
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          Doggoneit Steve, I had not even considered the effects of my 80 meter loop to my hexbeam. My hex is located only 15 ft or so from the corner of my 80 meter loop. Top element (20 meter) of hex is about 40 ft and loop is 35 ft or so?

          Do you still have the NEC files with both hex and 80 meter loop? Will the file work with 4NEC2?

          Thanks again for all the great work you have done developing the BBhexbeam - and other projects. I learn LOTS from your website.

          Ken H>

          --- In hex-beam@yahoogroups.com, "Steve" <steve@...> wrote:
          >
          > Trent,
          >
          > I tried modelling something like you describe. I had a 20m hexbeam at 30ft. I placed the corner of a horizontal 80m full-wave loop 10ft away. The loop tilted from a height of 12ft nearest to the hex and 20ft furthest away.
          >
          > The presence of the loop degraded the hex radiation pattern severely when the hex was pointing in the direction of the loop. The effect was a lot less - but still quite significant - when the hex was pointing away from the loop or at right angles to it. Probably not surprising as the loop is resonant and acts as a parasitic element on all odd and even harmonics.
          >
          > I guess that's not what you wanted to hear! I don't know how you are feeding the loop, but there may be some way of making it non-resonant when not in use by the way you terminate the feedline.
          >
          > 73,
          > Steve G3TXQ
          >
          > --- In hex-beam@yahoogroups.com, "trentkj4kaf" <trentkj4kaf@> wrote:
          > >
          > > This afternoon I was able to do lots of measuring and layout work for my new hex beam location. The best I can come up with puts it within 5 or 10 feet of my 80 meter loop. This is the lower portion of my loop that is about 12 or 15 feet. The Hexbeam will be at 30+ feet. Any thoughts about how this may be an issue?
          > >
          > > Thank You, Trent KJ4KAF
          > >
          >
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