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Need goop to coat antenna connector

Discussion in 'Electronic Repair' started by [email protected], Feb 14, 2005.

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  1. Guest

    I dont know how to explain this stuff, but there is some sort of black
    or gray putty like goop that I have seen that is used to seal things.
    I know they use it on furnace ducts and the like.

    What I have is a automotive CB antenna mounted on my metal rain gutter
    on my house. It's not for CB, but is for my police scanner.
    Considering it's not really tuned for scanner, I am amazed how well it
    picks up distant signals. However, I have a problem. The antenna
    works fine in dry weather, and even in rain. However, it gets screwy
    from snow. I am fully aware of why. It's because the snow piles up
    at the base and touches the connector where the coax hooks to the
    antenna. There is a large nut down there and it is exposed. It's
    located less than an inch from the rain gutter when mounted, so it
    dont take much snow to screw things up.

    What I need is a means to insulate it. I could use silicone caulk,
    and I know that would work well, but I want something that can be
    removed so I can get that nut off if I need to. I know because it is
    so close to the mounting bracket I could not get a decent wrap of
    electrical tape, and also know that tape tends to hold moisture once a
    little water gets in. But there is that black goop. It sticks real
    well, and is waterproof, and yet removes easily. Does anyone know
    where to get that stuff, or know of anything else I can use?

    Thanks

    PS. I am terrible at math. What wavelength is a CB antenna on a
    scanner? What I mean, is referring to half wave, quarter wave, etc...
    Anyone ???

    Mark
     
  2. Harvey

    Harvey Guest

    [...]
    Do you mean Self Amalgamating Tape?
    http://www.cybermarket.co.uk/ishop/923/shopscr1691.html

    That's the stuff I always use on plugs/sockets if they are exposed to the
    weather. Its looks a bit like electrical PVC tape, but it doesn't have the
    glue; instead you stretch it and it sticks to itself, eventually forming a
    fairly solid 'blob' of waterproofing. Easy to get off with a knife.
     
  3. Visit a decent hardware store (probably not a Big Box place) and ask
    the Olde Timer back in the electrical dept. for some "Elephant Shit".
    It's a grey, 1/2 brick-sized piece of putty-like stuff.
    Just what you want.
    Maybe tape over it after you apply it -- just to prevent its migration
    over time.


    HTH
    Jonesy
     
  4. Guest

    Right, sometimes called self fusing tape in America. I've used a
    silicone type that's suitable for buried video cable. That one's red.
    Richard
     
  5. Jamie

    Jamie Guest

    get your self a can of liquid tape.
     
  6. Just got back from the HW store (on some other errand.) Whilst there
    I checked: None of the "kids" ever heard of "Elephant Shit", but the
    Olde Timer did. And, it's probably not found in the electrical dept.
    It is as you thought 'duct seal', and it comes in 1 lb bricks.
    One brick ought to last you a lifetime -- even if you're an
    Amateur Radio Operator with a decent antenna farm.

    Jonesy
     
  7. You might be reaching the wrong conclusion. The problem could be snow
    static which is an accumulation of static charge or the discharge of charged
    particles.
     
  8. "COAX Seal" is what your looking for. It's black and sticky (sorta like
    tar) and sold in a roll. It's great stuff.
    If rain doesn't affect it, I'm surprised that snow does. AFAIK, snow is
    non-conductive until it melts.
    Radio Shack carries it and you can get it from Amateur supply houses.
    If nothing else, I'm sure you could find it here:

    http://www.coaxseal.com
    That would depend upon the frequency your trying to receive and the type
    of CB antenna. If your CB antenna is just a 1/4 wave (on CB) ground
    plane, then it will likely be anywhere from ~1/4 wave at 30Mhz to many
    wavelengths long on a trunk system.
     
  9. Harvey

    Harvey Guest

    That stuff seem to be the same as the self amalgamating tape I posted about
    earlier - I'm guessing its about the same sort of suff, just under a
    different name.
     
  10. Yep. My ham shack is down in the basement, and on these dark, cold
    winter evenings, I can usually tell when it's snowing -- from the
    pop-snap-pop-pop-snap-snap.... I hear from either the 6 meter or the
    2 meter rigs (or both.) I can also tell how _hard_ it's snowing -
    by the repetition rate.

    Less frequently, I'll observe the same effect with light rain.

    I have _never_ had 'piled-up' snow cause any such problems.

    Since you are _only_ using the antenna for receive, you could try
    running an RF choke from the base of the antenna to ground (to the
    outer braid of the feedline.) That could lessen the annoyance.

    Jonesy
     
  11. I think it's different. The coax seal is kinda thick >1/8". The tape
    your talking about is much like electrical tape that permanently bonds
    to itself after some time, isn't it?
     
  12. Harvey

    Harvey Guest

    The stuff I have is about 1/8" thick too, separated with a thin plastic film
    to stop it sticking together.

    The roll I have is about 15 years old (and still as good as new). I've had
    no need to buy any since so although I assume the stuff on the market these
    days is the same as I have, but I don't honestly know.

    This stuff I have actually 'melts' into itself over time, forming a solid
    blob after a few years that sticks to the coax but doesn't actually stick to
    the metal parts, and can be cut and pealed away if needed.

    I have also seen a sort-of duct tape / gaffer tape used before - that was
    like the normal duct tape but without the shiny backing - so it stuck to
    everything as a horrible gooey mess - not recommended - as it's a almost
    imposable to remove without getting it stuck to your fingers, hands,
    clothes, hair, carpet, dog, cat.....
     
  13. That sounds about the same, but the seperator is like wax paper.
    The coax seal seems to have a long shelf life as well.
    This is where it sounds a bit different. The coax seal bonds instantly
    to itself. You just wrap it around and then massage it a bit like putty
    and it's just one solid piece after that.
     
  14. TimPerry

    TimPerry Guest

    in addition to (or sometimes in conjunction with) the above mentioned
    techniques, 3m scotchkote is available at better electrical supply sources.

    it is usually applied after taping up a connection. just paint it on.
     
  15. Guest


    Thanks to everyone for the help. That coaxseal.com website referred
    me to Radio Shack which has the coax seal in smaller amounts for about
    $3. That solves that problem.

    Next time I get to the hardware store I got to ask for elephant shit,
    just for the heck of it. :)

    Charles said "snow static which is an accumulation of static charge or
    the discharge of charged particles.". Can someone explain what causes
    the static? I never heard of that.

    Mark
     
  16. You can Google for precipitation static, rain static, snow static, dust
    storm static, and so on. Essentially, when there is friction between two
    bodies (perhaps a snow flake and the atmosphere), electrons get transferred
    from one atom to another leaving a net charge. When the charged particles
    strike an antenna, they make nose since the imbalance is corrected by the
    antenna structure (electrons transfer between the particle and the antenna).
     
  17. Guest


    Thanks.
    I was not aware such a thing existed.

    Mark
     
  18. none

    none Guest

    I use plasticoat which can be gotten at most hardware stores.
    Normally used to recoat tool handles etc...
    Works great on CB antenna's ans such.
    Comes in three basic colors blue, red and white.
    But can be ordered in black as well.
     
  19. A man

    A man Guest

    You could use silicone caulk. It will get pretty firm when cured and will be
    easy to peel off if you need to.

    You can also use roofing sealer, which is a black, tarry substance. However,
    that appears more sticky and difficult to remove.

    Or try plumber's putty. It is designed to be used in wet conditions.
     
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