ZS6BKW antenna design in Inverted-V format

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by WB5UPS, Oct 16, 2009.

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  1. WB5UPS

    WB5UPS Ham Member

    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?
     
    Last edited: Oct 16, 2009
  2. KL7AJ

    KL7AJ Ham Member

    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
     
  3. WB5UPS

    WB5UPS Ham Member

    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. G3TXQ

    G3TXQ Ham Member

    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. WB5UPS

    WB5UPS Ham Member

    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. K8AG

    K8AG Subscriber

    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. WB5UPS

    WB5UPS Ham Member

    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. KL7AJ

    KL7AJ Ham Member

    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
     
  9. WB5UPS

    WB5UPS Ham Member

    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. G3TXQ

    G3TXQ Ham Member

    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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