My antenna snapped and I could fix it if...

Discussion in 'OnBoard Electronics & Controls' started by sdowney717, Jun 20, 2015.

  1. sdowney717
    Joined: Nov 2010
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    Location: Newport News VA

    sdowney717 Senior Member

    somehow a sleeve was available to slide down and glue it back together.
    The antenna mast looks like a fishing pole.
    I dont have a fishing pole I want to sacrifice.

    Any ideas on a cylinder of some substance that could be used?
     
  2. Jamie Kennedy
    Joined: Jun 2015
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    Jamie Kennedy Senior Member

    [​IMG]
     
    1 person likes this.
  3. AndySGray
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    AndySGray Senior Member

    These things lead a pretty hard life and you probably shouldn't even be considering it if it is over 5 years old. If you're sure the wire is intact (should be able to measure the resistance 50 ohms ?).

    As you say they are built like fishing poles and if you can glue it strong enough that you can spiral a length of fibreglass tape up it, you may get a strong repair though try and get it well worked and wetted. That's not to say you won't lose some signal strength.

    By all means try a repair but maybe keep in the shed as a spare and buy a new one, this is considered safety equipment.
     
  4. Jamie Kennedy
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    Jamie Kennedy Senior Member

    If it is a fibreglass whip is it still attached just splintered where it snapped? I think I would take out any loose material and then saturate it with thickened epoxy where all the splintered bits are letting the epoxy ooze up and down a bit betwixt the coax and the fibreglass. Then when that hardens or maybe all in one go wrap it with some fibreglass tape and epoxy. Once you start with epoxy you kind of have to keep going with it. I tend to botch these repairs though, so would end up with a nice kink no doubt. It could be a fun repair though I would go for it.

    Hey I just came across this. Apparently they break clean and not like I thought.
    Maybe better to do it their way...
    http://www.outfrontmotorsports.com/whip_antenna.htm

    [​IMG]
     
  5. sdowney717
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    sdowney717 Senior Member

    It broke half way up the mast.
    It is hollow inside, the antenna wire passes up the center.
    I was thinking glue a fiberglass sleeve over top of the break, but they dont seem to exist. So I suppose gluing on a fiberglass wrap with some cloth might work, and some epoxy.

    Unbelievably it broke in a storm with boat tied up in slip.
    I had the antenna loose for painting around it. Overnight, the winds managed to whip it into a position where it caught on the wooden piling, and it snapped as the boat was moving. So never leave things loose on the boat, they might get destroyed by wind.

    The inner wire is still intact. You can't measure the ohms with an ohmmeter. You can use a signal strength meter to measure the SWR, I have done that before.
     
  6. Jamie Kennedy
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    Jamie Kennedy Senior Member

    I think Andy had the right idea then. First epoxy it together at the break, just to hold it for the next step. Then wrap some wetted out fibreglass tape around the outside, which is where the strength of the repair will come from. It is tricky doing this because it gets slippery, so you have to tack one edge first, and you can do that along with the first step of gluing it all together, probably on a horizontal surface. Then once that has set, you can do the second step by getting the tape wetted out and then just wrapping it tight because now you have something to pull against. Once you have wrapped it to the last bit of cloth which can be left dry, you can tape it with duct tape to hold it all until it cures, and then grind away the dry stuff when you are done. I think that is roughly it.

     
  7. gonzo
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    gonzo Senior Member

    I have fixed them with a fiberglass wrap. If the wire is broken you can solder it first.
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Make a plaster mold just below the break and use this as a die for the repair, done with epoxy and some fabric. Split the plaster mold open (or make two halves), expose the wire and jig up the broken pieces so it'll be straight when finished. You might want to break off some more old 'glass for a healthy transition. Wax then wetout the mold, I'd use a few coats, the first maybe with some pigment in it. Toss in some fabric, when the goo goes green and lay in the wire. Back fill with thickened goo and wait for it to cure. If you used two halves, you can get a pretty reasonably looking thing, without a lot of sanding. If it's a tube like mold, it'll need some fairing.

    On the other hand, a couple of popsicle sticks and a hot glue gun might yield acceptable, if lumpy results too.
     
  9. peterjoki
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    peterjoki Junior Member

    Why not use a stainless steel tube to collar over the break? Glue it in place with epoxy. Won't ever fail at the same spot.
     
  10. gonzo
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    gonzo Senior Member

    Any metal will affect the tuning of the antenna
     
  11. peterjoki
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    peterjoki Junior Member

    Good point Gonzo! I didn't consider that.
     
  12. BertKu
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    BertKu Senior Member

    I also would suggest a piece of Stainless Steel pipe. I doubt it, that at that frequency, that a small piece of floating SS, has much of a influence. (as long it is not connected to the boat's earth) My experience with various aerials at 403 , 443 and 868 Mhz made from various materials is, that he will only be able to measure a difference in a controlled measuring environment. In his case the frequency is much lower. Bert
     
  13. sdowney717
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    sdowney717 Senior Member

    How about copper pipe?
    I have lots of that in size I can use.

    I ignored metal pipe as I thought it would interfere with the signal.
     
  14. BertKu
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    BertKu Senior Member

    sdowney, Yes, a copper should be fine. As long it is not covering from top to bottom, although magnetic waves are funny in their behavior. Should you cover it from top to bottom, you probably have a lightning conductor and aerial combined. All jokes aside. It should not have an influence of more than 0.01dB either way, plus signal or reduced signal. provided it does not touch ground. You may even get a better reception. Solder it first together, then put some glue-stick stuff on, push your copper part over it and test it out. Bert

    Pls Let us know the result.
     
    Last edited: Jun 22, 2015

  15. peterjoki
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    peterjoki Junior Member

    With my very limited knowledge of electronic engineering, logic tells me that interference from copper would be even more negligible than A4-SS due to its much better conductivity. Could be wrong though.

    As BertKu said, try to use the minimum length of pipe necessary to ensure a sound fix. My area of experience is wooden boat building, so I would naturally apply a good ratio for a scarf joint, about 1:10 (diameter antenna:length of pipe). Might be a little overkill though.

    Copper will oxidize and form a greenish/dull surface fast in saltwater. In this case that's a purely aesthetic consideration.
     
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