Big Fat Tinfoil Antenna

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KJ4IVD, Apr 19, 2017.

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  1. WA8FOZ

    WA8FOZ Premium Subscriber QRZ Page

    I made a 20-meter ground plane like this in my back yard one time, just for the heck of it. I used a 16 foot fiberglass pole to support a vertical strip of foil, and laid out foil radials on the ground. It "worked OK." I only used a few radials. I f I had put it on a 6-foot ladder and elevated the radials, I suspect it would have done quite well. Or I could have cut the radial foil into narrow strips and had more radials on the ground.

    I could have as well done the whole thing with plain wire of any sort, but I wanted something different...
    NH7RO likes this.
  2. N1OOQ

    N1OOQ Ham Member QRZ Page

    Sounds like a lot of work. If the idea is a temporary antenna, I'd probably just tack some wire to the bamboo like someone suggested. So it's too small for the current... so what? It's just a fun experiment, not life or death, and not permanent.
  3. NH7RO

    NH7RO Ham Member QRZ Page

    But wire is so, you know, boring.
    WB5YUZ, KB4QAA and AI6KX like this.
  4. AI3V

    AI3V Ham Member QRZ Page

    I think it would work.

    But I would build a wire quad.

    NH7RO likes this.
  5. NH7RO

    NH7RO Ham Member QRZ Page

    Rege's idea of a wire quad is good, too since you have much bamboo at your disposal. I would still go ahead and make foil antennas in the meantime but also try to harvest some spreaders for the next trip to the coast. Even a single element quad might be worthwhile. How tall does the bamboo grow there?
  6. K8JD

    K8JD Ham Member QRZ Page

    Using something like Renolds Wrap for antennas doesn't sound cost-effective !!!
  7. KK5JY

    KK5JY Ham Member QRZ Page

    The trick is to try it, and then post your results here so we can all admire your antenna ideas. ;)

    I would like to see somebody make an STL out of foil. It would have to be well-supported, but there's a LOT of surface area there.

    In between wire and foil, I wonder if you could wrap some of this [] or some of this [] around the bamboo you have? You could use it to make a helix, or wrap it around a small-diameter pole to make a large pipe-like structure. The copper would be much easier to solder to than the aluminum, but the aluminum tape could be clamped to the feedline. Both types of tape have adhesive backing, which makes them easy to attach to the bamboo.

    If you used the bamboo do construct a loop shape, and used that tape to wind a helix around the bamboo, you would have a helically-loaded STL [].

    If you are handy with bamboo, it would also be cool if you could make some kind of tall antenna support out of it. Even if you just string an inverted V beneath it, if you can somehow lash and weave together bamboo into a 30' or 50' tower, that by itself would be very cool.
  8. NH7RO

    NH7RO Ham Member QRZ Page

    There's a Japanese ham that has done a small foil-wrapped loop that he has mounted on top of his van. The loop is about 5" in OD and large enough that he was able to mount his vacuum variable inside across the gap. I'll try to find the site and post a link (can't recall his call right now).

    In Hawaii 50-60-foot tall bamboo is not uncommon. The piece I used for a 20M rotatable dipole mast was about 40 feet long before I cut the thinner top section off. Wish I had some like that down here; we have about everything else like Hawaii plant-wise (I just got back from Lowe's and my car is full of bougainvillea and hibiscus which will go in our garden). Might have gotten some bamboo if I could have!
  9. KW4TI

    KW4TI Ham Member QRZ Page

    This definitely has the Gilligan's Island vibe to it. If you do this the world must know with pictures of course!

    In order to get a good connection between copper and aluminum, often a sealed crimp connection is used. The best thing I would think would be to have some precrimped Cu/Al connection wires with you. In a humid environment, galvanic corrosion can occur rapidly between Cu/Al and compromise the connection. By having a sealed/crimped Cu/Al connection you can reduce that problem.

    Then you could wrap the Al part of the Cu/Al wire around the foil and use compression to hold it onto the tin foil, such PVC sheeting and zip ties or hose clamps to press the wires into the tin foil without breaking the foil.

    Since you're probably not going to be carrying huge amounts of power, you might be able to get away with twisting the copper and aluminum wires together very tightly and then covering the joint with silicone or liquid tape or something. Just keep in mind that a Cu/Al joint can corrode rapidly and produce intermittent connections and heat at the joint unless it is tightly made and protected.


    NH7RO likes this.
  10. NH7RO

    NH7RO Ham Member QRZ Page

    First came the Marconi, then the W8JK Special and now, for the 21st Century we bring you The Gilligan's Island Special made by the Tin Man---perhaps it could be used in the next season of Survivor?

    I can see it now---"Survivor Kermadec Islands---Hams vs. CBers"

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