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GUEST POST – Weatherproofing Antenna Coax by Paul AE5JU 12 - May - 2010

Posted by k9zw in Amateur Radio, K9ZW.
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I’ve asked my friend Paul AE5JU to author a few posts as With Varying Frequency approaches One-Thousand Web Posts, and he has touched up a piece he had done on Coax Connector Weatherproofing.

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I’m performing a little antenna maintenance today.

Here I’ve already peeled off the top layer of electrical tape, exposing the gummy butyl rubber wrap, which is Scotch 3M 130C. A similar product is sold called “Coax Seal”. This tape just from heat of the sun, bonds to itself forming a solid rubber mass.

Old Scotch 3M 130C Coax Seal

Old Scotch 3M 130C Coax Seal

The rubbery Scotch 130C has been sliced, peeled back, exposing another layer of electrical tape.

Peeled back

Peeled back

Now the electrical tape has been removed, revealing a nice, clean plug and socket.

Tape removed

Tape removed

Nor is there corrosion inside the plug and socket. The last time I had this down I had squirted in some Corrosion Guard.

Clean connection

Clean connection

Here are the materials required to put this back together. Note… for the electrical tape I use only Scotch 3M brand. It does not turn gummy and let loose with age and heat. This tape lasts far longer than the cheap stuff. The Scotch 3M 130C is in the larger box, and is quite thick and rubbery. Unlike “Coax Seal” it does not have a liner that must be peeled away. The silicone grease is by GC, there are other brands, and has high dielectric properties. Universal Radio sells a product for this purpose called “Stuf”.

Materials required

Materials required

Here I have squirted the silicone grease into the socket, and onto the plug, as well as onto the threads. It is difficult to see in this photo, but the idea is to fill all the cavities so that water doesn’t have a place to seep into even if it gets past all the other stuff we are putting on the connection. When I screwed it together some oozed out here and there. All of the excess was wiped away with a paper towel.

Silicone Grease Applied to connection

Silicone Grease Applied to connection

Start wrapping first with a layer of electrical tape, as stated before, Scotch 3M brand. Begin down on the coax and wrap with overlapping layers going up. But wait! There’s a twist! No, a real twist!

Begin the wrap with the tape stuck to the coax, and then twist the tape 180 degrees so that it is sticky side out. The reason for this is so that when you redo all of this next year there is no sticky residue all over the connection. Pull, stretch, and wrap the tape, overlapping by half, from the bottom up. When you get to the top make sure you have covered the threads. To finish, DO NOT pull and break the tape. It will be stretched and will later want to pull back and the end come loose. Relax the pull on the last wrap, then CUT the tape with a knife or scissors.

And alternative, suggested by a long time ham and TV station engineer, is to make this first wrap with plumber’s teflon tape.

3M Elec Tape sticky side out

3M Elec Tape sticky side out

Scotch 3M Elec Tape Wrapped

Scotch 3M Elec Tape Wrapped

Now, wrap the connection with the Scotch 130C (or Coax Seal), beginning at the bottom just below the electrical tape using overlapping wraps. Pull and stretch the tape as you go, and cover the threads at the top of the wrap. When finished mold the tape down smoothly with your fingers.

Scotch 3M  130C Wrapped

Scotch 3M 130C Wrapped

Now wrap one more time with electrical tape, only this time sticky side in, no twist. Begin down on the coax just below the 130C butyl rubber tape, and pull and stretch as you make overlapping wraps going up. When you have gotten to the top make one more turn, relaxing the pull, and then cut the tape, smooth it down with your fingers.

Scotch Elec Tape Wrapped sticky side in

Scotch Elec Tape Wrapped sticky side in

Put a Ty-Wrap over the end of the tape, just in case. It can’t hurt.

TyWrap prevents unwrapping

TyWrap prevents unwrapping

Weatherproofed Connection Hoisted Back Into Place

Weatherproofed Connection Hoisted Back Into Place

Now, doesn’t that give you a warm fuzzy feeling?

73

Paul

AE5JU

——————–

Thank you Paul AE5JU – do remember that Paul lives on the Gulf in major weather country where good weatherproofing is the difference between operating at will or having everything corroded & in-op.

73

Steve

K9ZW

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Comments»

1. vu2sgw - 13 - August - 2011

Detailed info, worth reading. In VU we do have heavy rain and that too for almost 4 months this will help us a lot.

2. Jim N7HQZ - 18 - August - 2011

I should have done this on my HF end-feed wire. I was in a hurry, and wanted to get the thing up before the wife or neighbours could spot me. The outcome: 80 feet of RG8 coax ruined. The shield was black the entire length, smelly water ran out when I cut the PL-259 connector off! The brand of tape DOES matter. Dont do like me and use the “crap wrap” $.99 a roll tape. I have a new roll of coax and will do it the “Paul” right way. Oh, and sneak it up in the cover of darkness, AGAIN! So much for “stealth”! Thanks Paul! 73!


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