Radar Reflector

Discussion in 'Boat Design' started by bulk-head, Dec 31, 2007.

  1. bulk-head
    Joined: Dec 2007
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    Location: Antigua

    bulk-head Junior Member

    Hexcel Texalium ?

    Working on a project in which I would like to increase the Radar reflective footprint of the structure. Does anyone have any experience with Hexcel Texalium cloth. Any comment on it radar refletive abilities ?
     
  2. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    Is it conductive? If not, then it won't do anything for the radar signature. You should get a sample and measure its conductivity. That will tell you if it's even remotely feasible.

    Radio waves induce currents in conductive material that then radiate back into space where the currents reach an edge or a sudden change in conductivity. The direction of the radiation is perpendicular to the edge. If the material is not conductive, you don't get the currents and you don't get the re-radiation.

    If it is conductive, then you might want to use it for interior webs that can be arranged as corner reflectors, and use plain glass tubes that would be transparent to radio waves for the outer structure.

    Aluminum is also reasonably compatible with glass in terms of thermal stresses, etc., so you might consider thin aluminum shear webs inside a glass structure. Just make sure the aluminum is professionally treated (FPL etch, CIAP coating, etc.) before bonding to it.
     
  3. bulk-head
    Joined: Dec 2007
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    bulk-head Junior Member

    Thanks for the feedback Tom. Guess Id better get a sample and start experimenting with it. I have no idea whether its conductive, have only seen it used for ornamental laminates and in composite materials catalogs. Few test panels and my radar should give me a better idea. Cheers and Happy New Year.
     
  4. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    When I was flying for the USN , we were out sailing and one of our patrol planes came for a visit.Dropped BEER! Good pals!

    They found my plywood boat by skin paint alone ,( They can find a periscope in heavy seas at over 100nm) but while they were orbiting , I yanked out my trusty WWII surplus life raft folding radar reflector.

    They claimed to be able to track me almost as easily as a "real ship" on leaving to a long distance .

    I don't know weather a ships radar would go over 100 miles , due to hight considerations , but at reasonable distances these folding ex liferaft units , (or a modernization) do work really well.

    Might be a place to start,

    FF
     
  5. bulk-head
    Joined: Dec 2007
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    Location: Antigua

    bulk-head Junior Member

    No doubt that a proper radar reflector would deliver the best echo. Problem with extra STUFF on small boats is that you cant practically leave the gear permanently rigged... so...as you know... it ends up in some bag, in some locker, buried under piles of some other handy STUFF. By the time you need it, the handy reflector is lost or that longliner has already chopped you in half.
    Be nice to build as much reflective ability into the structure from the start. I see that the radio controlled model guys and the backyard rocket men are playing with Texalium to try to generate a better echo for their launches. I just haven't seen the results. Does it work ? The stuff is not cheap.. Its an aluminized e glass fabric. The model guys report that it is indeed electrically conductive. "As for the texallium, it shows about .00015 ohm for a strand 12" long. Seems to conduct fairly well as far as my $12 Radioshack meter says.
    Jim " Just wondering if any boat guys or offshore fisherman have used the stuff.
     
  6. Mit
    Joined: Jan 2008
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    Location: New york

    Mit New Member

    it's coated with aluminum, so yes, it is conductive. Seen allot of it used in kiteboards. No idea if it's effective as a radar reflector but I hear that even aluminized mylar reflects fairly well so I would guess it should work. Local coast guard might be willing to help test it if you ask nicely.
     
  7. Ophion
    Joined: Aug 2008
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    Location: california delta

    Ophion Junior Member

    Radar Reflectors on a owens 25foot boat

    I have a 25’Owens flagship and operate it in ca delta near shipping lanes
    I am wondering when it gets foggy would it be a good idea to install a radar reflector.
    If so what type and on what do i mount it. I don’t have any type of mast like other people
    Thank you
     

  8. Crag Cay
    Joined: May 2006
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    Crag Cay Senior Member

    There seems to be a lot of contradictory evidence about enhanced radar signatures. Recently the MAIB of the UK CG did tests of most of the commercially available radar reflectors and found them all woefully inadequate. In particular it was the off axis performance that was pathetic, either due to rolling or heeling.

    Other tests have shown that most of the 'success' people have reported, perhaps after contacting passing ships etc, may have been as a result of the return from their engine block, rather than the radar reflector. The only enhancement that was really good, was an active transponder like the 'Sea-Me'. ( http://www.sea-me.co.uk ) I would save up for one of those rather than trying something totally unproved if being seen on radar is a priority.
     
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