Aluminum Antenna Fabrication

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N7GH, Sep 6, 2012.

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  1. N7GH

    N7GH Ham Member QRZ Page

    Hey I've been looking at doing some antenna work, but I am handicapped, amongst many other things, by the fact that I don't have any welding skills or equipment. Since I don't really want to put out bundles of money to hire a welder to join the aluminum, I've been looking around at various other options.

    Alutite -- aparently only available in Sweden
    DuraFix -- also seems to be scarce
    Alumaloy -- this seems to be readily available and is supposed to work better than Alumaweld.

    Has anyone used this type of stuff to "propane weld" aluminum?
  2. NA0AA

    NA0AA Ham Member QRZ Page

    Maybe we don't have enough information - why are you trying to weld aluminum? just in general, mechanical joints tend to be much more common in this application.

    If it's real structural welding, you probably need a pro who can do shielded arc welding - aluminum is pretty tricky as I understand it.
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I wonder that, also. Structural assemblies like towers and bicycles and stuff are usually heliarc welded, but why would an antenna need that?

    Most beam antennas are made from aluminum and don't include any welding.
  4. VK4TI

    VK4TI Ham Member QRZ Page

    Normally clamps and screws are normal fixing for alloy antennas , I doubt you ned to weld anything once you think it through and if you do just a weld or two can be done by your local engineering shop
  5. N7GH

    N7GH Ham Member QRZ Page

    I'm making an copy of a DB224E antenna--usually used on repeaters and electrically all points of the antenna are at ground level: everything is literally welded together. Its a 4 bay loop. Each full wave loop is welded together, the loops are each welded to a small strut, each strut is welded to the main mast. It's all one big chunk of aluminum when your done. I had to do some pretty good experimentation before I would believe that the design was just not someone trying to pull my leg, but it really works, even though, it's electrically at ground level. They are famous for taking lightning strikes and surviving.

  6. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    You are trying to replicate a very expensive commercial grade antenna. There are no short cuts. You'll have to use commercial grade welding methods.

    Either enroll in a welding curriculum, or make up drawings and take them to a machine shop or welding shop.

    p.s. I've tried those 'weld aluminum with a propane torch' sticks and found them unusable and highly prone to corrosion.
    Last edited: Sep 7, 2012
  7. W9GB

    W9GB Ham Member QRZ Page

    Decibel Products DB-224E Specification Sheet (Andrew brand name spec sheet)
    ​Still manufactured in North Texas

    DB-224E Detailed diagram (2005), from Doug Zastrow, WBØUPJ
    Element detail and phasing harness

    Catalog page:

    DB-224 Installation instructions (2003)

    dB Spectra
    Last edited: Sep 7, 2012
  8. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Yeah, I'm very familiar with that antenna and have owned several of them over the years (not homebrew, though) for repeaters.

    You can skip the welding if you replace the aluminum with copper tubing and just solder it with silver solder. That would make it slightly heavier, but not a lot. Copper's easy. BTW no real reason I can think of to weld the elements to the supporting mast; the most popular version of the DB-224 doesn't do that -- the mast is separate and the elements clamp to it. That's so the same antenna can be used on a tower leg instead of a mast, and in many installations that's exactly what's done. It's still just as grounded.
  9. KH6AQ

    KH6AQ Ham Member QRZ Page

    The aluminum brazing rod sold at Home Depot works very well. The joints I have made are stronger than the aluminum tubing. But it can barely be brazed using a propane torch. A MAP gas torch is the thing to use.
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