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7184Re: shielded loop

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  • Pronto. (Military)
    Feb 3 7:39 AM
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      Because the RF currents run on the "skin" or surface of the metal, You can use copper plated steel for lightness and strength. Remember many of our military whips in the past had that construction. Today they tend to use fibreglass.
      At VHF and UHF the plating is frequently silver plated for conductivity but at HF frequencies copper plating is sufficient and even unnecessary.
      You could use thinwall copper tubing if you can source some.
      Copper becomes magnetic at high current but because , in our case it is oscillating at high frequency, it doesn't show.
      I used to work in a copper mine where 1200 amps DC would run through bus bars and you couldn't walk nearby without having your wrist watch destroyed. Carrying a tool box nearby was downright frightening. Fortunately the voltage was low.
      I am currently considering building a loop antenna in a square configuration using copper plated steel sections or at least plated where the junctions are. My objectives are lihtness , portability and simple takedown/assembly.
      Jim VE3DDY/W4



      --- In loopantennas@yahoogroups.com, "dannibou" <dannibou@...> wrote:
      >
      > Hi! On the topic of shielded loop, can anyone tell me if the metal for build a loop is important electrically speaking. I've read on this group that aluminum or copper are preferred. Is this because they are non magnetic metal? I have a round piece of metal that I could use to build a shielded loop but it is magnetized metal. Any idea? Thanks
      > Danny
      >
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