JUNGLE JOB ANTENNA - G4ZU

Discussion in 'General Technical Questions and Answers' started by F8DRA, Aug 22, 2007.

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  1. F8DRA

    F8DRA Ham Member QRZ Page

    If someone has already tried this antenna, i'll be very happy to have his opinion !


    This antenne looks like a spiderbeam antenna in my opinion but i'd like to have the owners' opinion anyway ;)


    Best regards to all !

    F8DRA, Marc
     
  2. VK2TIL

    VK2TIL Ham Member QRZ Page

    I haven't tried it but I have read about it.

    An article by Dick Bird G4ZU showed better F/B ratio than a 3-el Yagi in the 10-metre band. The close element spacing which gave good F/B ratio produced a feedpoint impedance of 20-25 ohms.

    The antenna is a relative of the VK2ABQ / G6XN designs that use "critical coupling" between the ends of the driven element and the parasitic element.

    PM me with your e-mail address and I will send you a copy of the article I have.
     
  3. K8JD

    K8JD Ham Member QRZ Page

    does that work like like the "Moxon" design?
     
  4. VK2TIL

    VK2TIL Ham Member QRZ Page

    Les Moxon G6XN (SK) had a lot of "designs"; one used the "critical coupling" concept.

    http://web.ukonline.co.uk/g3ldo/bya_errata.htm

    G4ZU's "Jungle Job" may have been so-called because it was first built as a "quickie" in Africa or because the original used bamboo or because it looks like an archery bow or, perhaps, all of the above. [​IMG]
     
  5. F8DRA

    F8DRA Ham Member QRZ Page

    Hi,i don't know if it works better or not than the Moxon antenna but we have approximatly the same antenna !
    I would like to thank you Kerry for your Mail, articles are very interesting you know ! i'm going to read them carefully.
    Now, i don't know which one i'm going to built either the JJ or the VK2AQB Antenna [​IMG]?
    About the Moxon, i've just downloaded the MOXON FreeWare and it gives also an interesting result ( Lengths speaking ).

    I'm going to study i little bit more before building Hi Hi but if someone has already tried one i'm still interested in any opinion and comparison tests.....


    73 to all and thanks again Kerry !


    F8DRA, Marc
     
  6. VK3NEA

    VK3NEA Ham Member QRZ Page

    Hi Kerry
    I have made up and used this antenna from the article that vk2TIL has in the early 90's (VK2ABQ)
    Looks like a bow and arrow, works like a steam train.
    Uses the same turning space of a single dipole.
    Compares well to a 3 element yagi.a good little antenna project,
    Play around with the length of the reflector element.
    Also the distance between the ends of the reflector and driven element.
    I think it was suggested that the reflector is the same
    length as the driven element I would start with 3% longer
    and fold it back to shorten it till you get the results you want
    Good luck with it
    Alan
     
  7. VK3NEA

    VK3NEA Ham Member QRZ Page

    So it looks like a bow and arrow when its a 2 element
    hence the name jungle job
    I looked up G4ZU antenna it is the same but with a director element added.
    Just one small difference the one I built the driven was pulled back like a bow because it was a 2 element,well i don't know if it was for asthetics or to squeeze every bit of gain out of it..
    Go for it make up the G4ZU antenna it will surprise you
    with its performance.
    Alan. VK3NEA
     
  8. F8DRA

    F8DRA Ham Member QRZ Page

    I'm back again with this idea !!!!

    Hi,

    As i'm still looking for a good compromise on 20m, i remembered the existence of this Topic !

    As i'm not allowed to put up any big antennas ( Historical Classified Village ) i have had again the idea of the Jungle Job antenna.

    But, is it a good choice ?

    It is not a very tall antenna, however it seems to be quite effective and competitive......

    The one i'll be interested in will consist of a 2 elements ( radiator + Reflector ) the reflector will look like a V you know what i mean. It seems to be the more effective configuration.

    The F/B ratio announced is quite interesting too .

    I would like to find the Exact Lengths in order to build one. ( Elements lengths , space between elements etc....) If someone would have these informations i'll be very happy :D

    I'm also looking for any opinion and testimonies about this antenna....

    Have a nice Sunday .

    Best 73'

    F8DRA, Marc
     
  9. DL9NEF

    DL9NEF Guest

    Hello Marc!
    You will find the infos you requested here:

    http://www.cqham.ru/junglejob.html

    Although the text is kyrillic, the infos about the lenghth and space between elements are given here. vy 73 de Johannes, DL9NEF
     
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