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Thread: ZS6BKW antenna design in Inverted-V format

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  1. #1
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    Question ZS6BKW antenna design in Inverted-V format

    I am considering putting up the ZS6BKW antenna within the next several weeks. However, due to space constraints (and nearby power lines), I can't go with the dipole version.

    I plan on using #14 PVC Insulated Flex-Weave due to my coastal environment and will be feeding it with 450 ohm ladder-line. The peak will be around 40 feet high.

    Do you have any experience and/or advice with the ZS6BKW in an inverted-v design?
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    Last edited by WB5UPS; 10-16-2009 at 09:57 PM. Reason: added attachment

  2. #2
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    Quote Originally Posted by WB5UPS View Post
    I am considering putting up the ZS6BKW antenna within the next several weeks. However, due to space constraints (and nearby power lines), I can't go with the dipole version.

    I plan on using #14 PVC Insulated Flex-Weave due to my coastal environment and will be feeding it with 450 ohm ladder-line.

    Do you have any experience and/or advice with the ZS6BKW in an inverted-v design?
    Though I don't have direct experience with that antenna, almost any wire antenna will work fine as an inwerted wee with a little twiddling.


    eric
    "The more you know, the less you don't know."

  3. #3
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    Quote Originally Posted by KL7AJ View Post
    Though I don't have direct experience with that antenna, almost any wire antenna will work fine as an inwerted wee with a little twiddling.


    eric
    I understand. Like most all of us, I'm wanting the most bang for the buck. I have an old MFJ tuner that I'll be using to make the most of it. I plan on feeling my ladder-line straight to my tuner and then coax from it to my rig.

  4. #4

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    It should work fine, provided the angle between the two legs is not too small - certainly not less than 90 degrees. That means the ends need to be at least 10ft high if the centre is at 40ft.

    If you run the ladderline all the way back to the tuner and it's no longer 40ft long, strictly speaking it's not a ZS6BKW! But don't worry, it'll work just as well

    73,
    Steve G3TXQ

  5. #5
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    Thank you for your input Steve. I'll have both legs at a 90 deg angle. However, it looks I'll have to lower the apex down to around 35 ft to get my ladderline into my shack at a 40 ft length. I want this to be a true ZS6BKW. I'm looking forward to getting this thing up in the air, and on the air!

  6. #6

    Default ZS6BKW in inverted V config

    Hi,

    I have run a ZS6BKW for years, but in a more or less flat top between two trees. I did read a web site several years ago that indicated the inverted V cancels radiation quite a bit. There was a graph that indicated it was significant (like 3db or more). I have since lostthe link. Sorry.

    Good luck.

    73, JP, K8AG

  7. #7
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    Quote Originally Posted by K8AG View Post
    Hi,

    I have run a ZS6BKW for years, but in a more or less flat top between two trees. I did read a web site several years ago that indicated the inverted V cancels radiation quite a bit. There was a graph that indicated it was significant (like 3db or more). I have since lostthe link. Sorry.

    Good luck.

    73, JP, K8AG
    Seems like I read something about that as well. Can't remember where. Although from what I know, any inverted vee will suffer from radiation cancellation if the angle between the two legs is less than 90 degrees. True?

  8. #8
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    Quote Originally Posted by WB5UPS View Post
    Seems like I read something about that as well. Can't remember where. Although from what I know, any inverted vee will suffer from radiation cancellation if the angle between the two legs is less than 90 degrees. True?
    It STARTS to show radiation cancellation at anything less than 180 degrees~!

    90 degrees is just an arbitrary number. It's worse than 180 but better than 3!

    eric
    "The more you know, the less you don't know."

  9. #9
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    Quote Originally Posted by KL7AJ View Post
    It STARTS to show radiation cancellation at anything less than 180 degrees~!

    90 degrees is just an arbitrary number. It's worse than 180 but better than 3!

    eric
    Wow, ok. I'm learning something new every day! Thanks for your reply Eric. So, in a nutshell - with an inverted vee, within my space restraints, the closer I can get the two legs to 180 degs, the better off I am - with regards to the radiation cancellation. Correct?

  10. #10

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    Once the included angle is less than 180 degrees, there is a vertical component of current in one dipole leg which is antiphase to a vertical component of current in the other dipole leg. The smaller the included angle, the higher this vertical component of current.

    However, this doesn't mean the antenna radiates less - it just means that the radiation resistance decreases. In other words you supply more current into a smaller resistance, but still radiate the same amount of power.

    73,
    Steve G3TXQ

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