Best way to splice together two pieces of small coax?

Needed to splice together two pieces of small coax (like 174 or such) and was not satisfied with my final result. It *works*, but really needs to be done better. What is the best way to splice together two pieces of small coax?



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"Dave" wrote in news:X4CdnWm_qrl3XP3SnZ2dnUVZ snipped-for-privacy@posted.internetamerica:

Attach two connectors. Not cheap but looks nice.

Reply to
Sjouke Burry

Two SMA connectors, one male, one female.

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Reply to
Fred Abse

You don't. The splice will leak, and break the impedance of the coax.

Either get a larger piece of coax, or as others point out, add connectors (male and female, or the same gender with an adapter). The best choice, and actually easiest solution, is the larger piece of coax, the connectors are likely expensive.


Reply to
Michael Black

Yes, thank you. I am looking into replacing the entire piece of coax, and the alternative of using SMA crimp connectors (unlikely, but worthy of consideration.) Thanks to all for the input, and for helping me understand better what I am actually looking at. Much appreciated...


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In a pinch, I have had some success with the following. Note, however, tha= t there's still going to be an impedance discontinuity at the splice, and t= hat any such splice should be avoided unless you have absolutely no other o= ption and need to get the coax reconnected right now.

  1. Cut the coax so that you have two clean ends. Remove the outer insulati= on about 1" back on each end, and peel back the shield so that it lies back= out of the way against the outer insulation. This works much better, of c= ourse, if you're dealing solely with a braid shield; if there's foil undern= eath, try to pull it back as well without removing any. Slide some heat-sh= rink tubing, about 2" long (and if you have any of the right ID), over one = of the two cable ends.

  1. Remove the inner insulation to expose 1/2-3/4" of the inner conductors.

  2. Slip a bit of thin heat-shrink tubing over the inner conductors; if it's= possible to push it back under the shield/outer insulation, so much the be= tter. If you can't get a piece of heat shrink in there, you'll have to ins= ulate the inner conductor joint with a bit of electrical tape or some such.

  1. Join the inner conductors using a classic "Western Union" splice and a b= it of solder. Don't let the solder glob up on the splice - the idea is to = get something not too much bigger than the original inner conductor.

  2. Insulate the joint either with the bits of heat-shrink put on earlier, a= little electrical tape, whatever; even with the heat-shrink, you may need = to add a top layer of tape. The idea is to get a layer of insulation in her= e roughly the same OD as the original inner insulator.

  1. Bring the shields back over the insulated splice from each side. You pr= obably will not be able to get the two shields to touch very well or overla= p sufficiently for a good joint. Use a bit of copper foil tape wrapped arou= nd the joint to give you some place to solder both shields to. Again, the = idea is obviously to replicate as closely as possible a continuous shield i= n the final result. Tack solder the shields to the copper tape all around.

  2. Cover the splice with the outer heat-shrink tubing added earlier, or usi= ng electrical tape.

Again, this is NOT going to perform anything like a continuous piece of cab= le, and I mention it here only because there are some time when you NEED to= get a cable back together and have no other options. Don't put the splice= anywhere that the cable is going to be bent much, and plan to replace it w= ith a new continuous run as soon as you possibly can, or at the very least = with a couple of new connectors as others have mentioned. This is most cer= tainly a poor substitute for doing a proper splice with connectors, but it = can often be better than nothing at all.

Bob M.

Reply to
Bob Myers

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