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Thread: Soft Welded 500 Miles of Train Rails as DX SW and ELF Antenna

  1. #1

    Default Soft Welded 500 Miles of Train Rails as DX SW and ELF Antenna

    Hello there,

    I am from Istanbul Turkey , living close to newly built train rail system. Our rails have been welded end to end with soft metal which allows the rails expand or reverse with heat. I am inspired with ELF submarine transmitter antennas and want to use rails as my short wave antenna or elf transmit antenna. What do you say , is it allright or not possible.

    Another idea is to try my TECSUN PL 310 ET radio on rails. Does rails increase the reception ? I am corona locked in and not want to go out before vaccine. I am thinking loud about above ideas.

    thank you very much,

    I wish the good health and best of luck,

    Mustafa Umut Sarac
    Istanbul

  2. #2

    Default

    https://1.bp.blogspot.com/-NAk7KCvDt...40/Railway.jpg

    Snipped from, https://ham.stackexchange.com/questions ... ire-dipole
    The unbroken conductor is your existing wire; the parallel wire with the feedpoint is a wire you add. Keep them roughly parallel with some non-conductive spacers.

    Inherent in a folded dipole is an impedance step-up, since only some of the current flows in the half with the feed. If you make the wire you add smaller, then you get a greater impedance step-up. If you make the wire you add equal in diameter, then you get a 4:1 step-up. For "fat" wire you could use just the shield of some cheap coax. Flat braided wire could work also.

    I'd run this, via ladder-line, to a tuner. This will allow you load up your wires on just about any band and get reasonable performance. Ladder line works better than coax in this application since it has much lower loss and is cheaper, and the SWR on the transmission line could be pretty high.

    Another option would be a delta match. Simply take your ladder line feed and cut it down the middle for some length. Then attach the two ends at some points centered on the wire:
    You can think of this working as an autotransformer, with the dipole being a single-turn, straight inductor. By adjusting the connection points you can get different feed impedances. This was, back in the day, a very popular way to feed a half-wave dipole with 600-ohm ladder line. Find the best arrangement by experimentation.
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  3. #3

    Join Date
    Nov 2017
    Location
    With my wife
    Posts
    206

    Default

    I wonder how the operating train alters the tuning and lobe patterns...

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