Bob Martin’s “No cut” Antenna idea, NOW with Silicone!!

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  • QuarterMaster
    No one
    • Jul 2003
    • 607

    Bob Martin’s “No cut” Antenna idea, NOW with Silicone!!

    Too be honest, I was so impressed with Bob’s “No Cut” Antenna method, that I decided to replace two of my 75mhz RCVR’s that had been cut, with new 37.4” antenna leads. I really like the benefits of not cutting the antenna, regardless of what school you’re in with the performance issues of that, and that it can be used for pressure testing your “pressure hull”. I’m of the school, less hull openings, less chances of failure. (KISS)

    I always state “Murphy’s Law” is a “Clear and Present Danger” in my life.

    The need was due to a “straw breaking the camels back” with a series of nasty glitching issues when I performed a functional test of PROTEUS’s Command and Control systems. Again, regardless of which school you’re in with the real/imaginary performance issues of cutting the antenna, I wanted to eliminate ANY possibility because at one point it seemed I was chasing a ghost.

    I have a lot of function, crammed in a small area. So along with shortening Servo leads, minimizing possible GND loops, use of a separate BEC and isolating the ESC BEC for BOTH, a 2200uf 6.3V cap on a spare channel, etc, I replaced the antenna.

    Unfortunately, I used what I had, 22 AWG White Silicone wire. I previously eliminated PVC insulated in all my builds. I enjoy the flexibility of the silicone, as well as it’s heat resistance. Ever lose an 1/8”+ when you tin a PVC lead?
    So, after the lengthy thought process that really wasn’t necessary to share, I encountered a problem, and subsequent workaround.

    So here I have a lengthy piece of wire, with silicone insulation, ready to feed through a lengthy 1/8” ID silicone tube.

    Try that, will you? I’m assuming Bob had the original PVC jacket on his antenna lol. Talk about soft spaghetti and they eye of a needle! You will discover, maybe again (much to your chagrin) the amount of silicon on silicone friction can frustrate you.

    I also don’t recall the exact method Bob employed to “thread the needle” regardless of insulation material.

    Lucky I had recently purchased some 2mm x 250mm Carbon Fiber pushrods. So all it took was that (or similar object), and some very small diameter shrink tubing.

    SO after you get setup, adding the “bearing tube” through your bulkhead and what not. Feed the antenna from the inboard side all the way out. Then feed the rod through an appropriately sized silicone tube. Make sure the rod is longer than the tube lol.

    So at that point, join the two together with a length of the heat-shrink tubing as shown.

    Click image for larger version

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    Then you merely need to pull the antenna back through the tubing. Should the rod pull off, reset with a longer length of shrink tubing. When done, you might as well fit the tubing over the hull “bearing tube”. If you cut the tubing just right, it will end up like this after it’s through and the tubing is attached.

    Click image for larger version

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    Notice how it’s recessed a “tad”.

    So you’ll have to pull a bit more while holding (low pressure pinch) the end of the silicone tube, enough to expose the heat shrink section where the antenna and rod meet.

    Click image for larger version

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    Then just “guillotine” them apart with a sharp razor and let the antenna pull back into the tube. Cap with a fuel line plug or similar, an you’re done!

    Click image for larger version

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    As a belt and suspenders man, I did place a 3/16 ID o-ring on the hull “bearing tube” before I threaded the antenna itself through it. It just gives me that much more comfortability with the seal. Probably not necessary, but it’s over engineering that makes Ed; “Sub” Ed.

    Click image for larger version

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    Seeing how nice and clean my antenna is, away from other electronics, motor fields, wires and what not, I’m a happy man Thanks again Bob for a great tip.

    PROTEUS is now as quiet as a mouse.
    v/r "Sub" Ed

    Silent Service "Cold War" Veteran (The good years!)
    NEVER underestimate the power of a Sailor who served aboard a submarine.
    USS ULYSSES S GRANT-USS SHARK-USS NAUTILUS-USS KEY WEST-USS KRAKEN-USS PATRICK HENRY-HMS VENGEANCE-U25-SSRN SEAVIEW-PROTEUS-NAUTILUS
  • bob the builder
    Former SC President
    • Feb 2003
    • 1360

    #2
    Credit where credit is due! I originally got the idea from Greg Sharp! He da man! Thanks, Ed.
    The Nautilus Drydocks - Exceptional Products for the World of R/C Submarines - www.nautilusdrydocks.com

    Comment

    • QuarterMaster
      No one
      • Jul 2003
      • 607

      #3
      Originally posted by bob the builder View Post
      Credit where credit is due! I originally got the idea from Greg Sharp! He da man! Thanks, Ed.
      AGREED, another of the GREAT pioneers!!
      v/r "Sub" Ed

      Silent Service "Cold War" Veteran (The good years!)
      NEVER underestimate the power of a Sailor who served aboard a submarine.
      USS ULYSSES S GRANT-USS SHARK-USS NAUTILUS-USS KEY WEST-USS KRAKEN-USS PATRICK HENRY-HMS VENGEANCE-U25-SSRN SEAVIEW-PROTEUS-NAUTILUS

      Comment

      • X Bubblehead
        Member
        • Sep 2017
        • 59

        #4
        As an alternative, if the class of boat is equipped with a towed array, why not run the antenna out of the towed array bellmouth? Make it black and it has a dual function. I don't think I've seen anyone do this yet.

        Comment

        • Ralph --- SSBN 598
          Junior Member
          • Oct 2012
          • 1417

          #5
          Towed arrays end to end up around the propellers.
          Nothing like your boat out 100' or more and just stop responding to throttle.

          Comment

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