Need Manual for Old version Cushcraft A4S Yagi

Discussion in 'General Technical Questions and Answers' started by WX9DX, Nov 3, 2009.

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  1. WX9DX

    WX9DX XML Subscriber QRZ Page

    Help needed please!

    I have an older version A4S Cushcaft tri-band Yagi antenna. The dipole needs to be re- measured and then checked with an antenna analyzer. I don’t have the original manual. The dipole has been cleaned, and because of that we don’t know any of the measurments on the dipole, which we need drastically to get this project done... :eek: The people at MFJ have no clue as to what the original antenna looked like or anything, as I was told on the phone today. If you have the original manual or know where it can be down loaded please let me know! Winter is coming on very quickly and I sure would like to use this antenna this year:)

    I do have the test equipment to do it the hard way if I have to. But I sure would rather have the manual to help to do it a little quicker! ;)

    On the Original antenna the dipole went inside the center insulator. The new version the dipole goves over the outside of the center insulator. I have the older version. If you can help me please e-mail me!

    Jimmy, wx9dx at
  2. W9GB

    W9GB Ham Member QRZ Page

    Cushcraft A4S Manual - circa August 1998
    Jim -

    Cushcraft always used a Driven Element that was insulated (using fiberglass tube) from the antenna boom.
    So I really don't know what you are referring to when you talk about "inside or outside" the center insulator.

    Are you talking about the A744 add-on kit, that is a 40m (or 30m) dipole??

    Cushcraft did make the ATB-34, 4 element HF yagi in 1970s -- which is what the A4S eventually became!!
    You can find that ATB-34 manual (circa 1979) at:


    BAMA Mirror

    KN5L also has this ATB-34 manual scanned (5 pdf pages)

    Here is an Internet article by DK4QT in Germany for the complete cleaning and rebuild
    of a 30 year old Cushcraft ATB-34. Photos, GDO trap tuning techniques, replacement stainless steel hardware, etc.
    DK4QT - Page 1

    Page 2 - Shows rework of original Cushcraft balun

    If your Cushcraft is that old -- it is before Cushcrft used stainless steel hardware.
    With antennas of this age --- go to a larger hardware or marine store that stocks
    stainless steel hardware. At worst, you can order on-line from McMaster-Carr and
    have the hardware next day from the Elmhurst, IL regional warehouse.

    TowerTalk (2003)
    My Cushcraft ATB 34 is almost 30 years old and still performs flawlessly.
    The ATB 34 was the fore-runner of Cushcraft's current production A4S antenna model.
    The element spacing and boom length is exactly the SAME for the ATB-34 and A4(S).
    You can download the A4(S) manual from Cushcraft (above) and get those dimentions.
    The MAJOR DIFFERENCE between the earlier ATB-34 and the A4(S) is the trap design.
    For element length you could also use the A4 manual and you'll be VERY close until you get the ATB-34 manual.
    The ATB-34 also used a standard 1:1 balun attached at the driven element (below boom),
    instead of coiling the coax cable to create a choke balun.
    -- John, KB4CRT
    Last edited: Nov 3, 2009
  3. WX9DX

    WX9DX XML Subscriber QRZ Page

    Your a God Sent! Thanks! Big time!!!

    That is what this is exactly! An ATB 34. I have had it almost 30 years and for somereason I just started calling it an a4s. But your right and now I have the manual because of your help!!!!!!!!!!!! Greg thanks big time!


  4. WX9DX

    WX9DX XML Subscriber QRZ Page

    Thanksssssssssssssss Greg!!!!!

    Thanksssssss Big time Greg you have been of great help to this old man LOL... I now have the correct Manual!!!!!:D
  5. W9GB

    W9GB Ham Member QRZ Page

    Jimmy -

    Your welcome.

    IF someone in Michigan is looking for a quick autumn project (before the snow flies), there is a Cushcraft ATB-34 on eBay currently -- but it requires pick-up (Flint, MI area -- no shipping).

    As noted in the documents (referenced earlier), the major difference between this antenna and the A4S is the trap design as well as stainless steel hardware used on the A4S.
    The ATB-34 uses an early 1970s trap design (easy to repair) versus the current A4S trap design (1980s).

  6. WA7KKP

    WA7KKP Ham Member QRZ Page

    FYI --

    The antenna in question is the Cushcraft ATB-34. Dimensions may vary slightly, but it should be fairly close to the dimensions of the A4S.

    Put it together and see what happens.

    Gary WA7KKP
  7. N6DCN

    N6DCN Ham Member QRZ Page

    I happen to have that antenna. And until last christmas the box was never opened. I have all the paper work that came with the antenna new. I can copy it and send it to you snail mail if you wish. Good luck Jimmy

  8. KC8VWM

    KC8VWM Subscriber QRZ Page

    Last edited: Nov 4, 2009
  9. WX9DX

    WX9DX XML Subscriber QRZ Page

    it's up and works great!!!!!!!

    I built a new Balun " Home Spun" ;) on the same ferrite rod! Used stainless hardware everyplace on the antenna. I was 20 over to a station in Serbia!
    Also talked to a station in Florida yesterday for almost an hour like a phone call! Thanks guys for the help!!!!!!!!!

    Jimmy :D
  10. WA7PRC

    WA7PRC Ham Member QRZ Page

    Re: it's up and works great!!!!!!!

    Hi Jimmy,

    That's great! I've found that, while forward gain is always a good thing, when the band gets crowded, good front-back and front-side ratio is an even better thing!

    Threaded fasteners made from stainless steel tend to seize together if you don't use antiseize compound. The stuff's a tad messy but worth its weight in gold.

    vy 73 es gud dx,
    Bryan WA7PRC
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