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5 and 8 element beam plans.

Discussion in 'CB Antennas' started by MonsterAudio, May 1, 2011.

  1. MonsterAudio

    MonsterAudio Member

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    does anybody know where to get plans for a 5 and 8 element beam?
    outside of Maco and the other main builders, im looking for some tested plans for those 2 sizes to experiment with.
    Im really looking for a long boom design for each, any ideas?


     

  2. Henry HPSD

    Henry HPSD 19DX348

    Joined:
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    11 meter Dx antenna systemx
    or All about antennas (were still working on that one)
    or drop me a mail (or put it here on the forum) containing:

    -boomlength
    -element diamters (incuding tappered length if there is any)
    -if your planning on using other material then aluminium please do mention.
    -What is your idea of matching?

    Another question would be...what is it what your looking for?

    What happens...
    Say you have a so called long boom...though this sounds nice,
    it is a yagi with a relative small number of elements on 1 boom say 18 feet 4 elements.
    That will provide high gain! true !
    But it has some downsides, often long boom high gain yagis will provide a low impedance, they will have a relative small swr bandwidth, the antenna will be a cricital one and will not allow construction error and will become more critical for noises from rain etc.

    The solution to that is to add a additional element in front of the radiating element.
    Thats known as a "owa" design.
    Now you have got a 5elements on a 18 foot boom The forward gain will be more or less equal to the previous mentioned 4elements on the same boom.
    (as gain primairily comes from boomlength)
    But the SWR bandwidth has become much wider.
    The impedance will be much higher..infact it can be around 50ohms, that means there will be no losses in matching networks :)



    Regards,

    Henry
    11 meter Dx antenna systemx
     
    #2 Henry HPSD, May 1, 2011
    Last edited: May 1, 2011
  3. HiDef

    HiDef Active Member

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    FWIW I copied Maco's 5 element design a few times after looking around for a long time. One time I used a hairpin match because the antenna was made out of a hacked up tribander with a split driven element.
     

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