Technical Articles

How to Make Your Coaxial Connectors and Cables Weather-Resistant

Moisture is the enemy of coaxial cable. Once water or condensation gets into your coax cable or connectors, it can cause problems such as corrosion and high SWR. Fortunately, you can fight back with some relatively simple solutions.


Your choice of materials for weather protection is important. Not only should they be waterproof, but they should also be made of a material that is resistant to damage caused by UV light.

Coax Seal and other mastic sealing materials have been around for a number of years. Actually, they work pretty well for sealing out moisture and corrosion. However, it’s a pain if you need to redo a connection. The gummy black material requires some effort to remove, with bits and pieces becoming stuck on threads and contact surfaces.

A better solution is to use a combination of two 3M products, Temflex 2155 rubber splicing tape and Scotch Super 33+ vinyl tape. These materials can be used either indoors or outdoors, and they provide a double layer of protection that can be easily removed if necessary.

Start by cutting a piece of Temflex—eight inches if you’re covering an antenna or balun connection, and 15 inches if you’re covering a splice with a barrel connector joining two PL-259s. Remove the white backing. Place the Temflex at least one inch before the end of the PL-259 and stretch the tape as you wrap, overlapping 50% of the tape width with each turn until the connectors are covered.

To block UV radiation and provide an extra layer of protection, add a layer of Scotch 33+ tape.  Start one inch before the previous layer of Temflex and wrap firmly, overlapping 50%—just as you did with the Temflex.

In the event you need to remove the weatherproofing, carefully cut the wrap lengthwise with a hobby or snap-off knife. Peel off the tape and look at the connectors—they should look nearly new.

Got You Covered

Coax isn’t the only item that needs to be covered. What about exposed screws and connections on wire antennas, coils, and traps? And don’t forget any splices you have made. Simple splices can be weatherproofed in several ways. You can slide adhesive heat shrink tubing over a splice, blast it with a heat gun, and you’ve got it covered. Another option is using heat shrink self-solder wire splice connectors that let you make permanent, waterproof electrical wire connections with nothing more than a heat gun. Liquid tape also seals splices—just be sure to put on at least two coats.

Exposed hardware can corrode over time, making it difficult to remove and reducing electrical conductivity. A light coating of Loctite or Permatex dielectric grease can protect these connections, which can still be disassembled easily if needed. Liquid tape is a more permanent alternative since it can be difficult to remove.

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  1. Pingback: How to Make Your Coaxial Connectors and Cables Weather-Resistant - Ham Radio News

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