GBPPR Tech Bulletin #1 - Waterproofing RF Connectors


Waterproofing RF connectors is a concept amateur radio operators fail to recognize.  When you're dealing with weak signals or a repeater system with a dynamic range of 140 dB, that Radio Shack education just doesn't cut it.

There are alot of different ways to protect and waterproof your RF connections, some actually work!

Just because you've been doing something wrong for 30 years doesn't mean it's right!

All GBPPR members are required to follow this bulletin.  If you put CoaxSeal directly on a RF connector, I will hunt you down and shoot you.

  1. Wrap the entire connection once (or twice) with 3M Scotch Super 88 or 88T PVC electrical tape.  Super 88 is recommended over Super 33 or the other crap because of its ideal temperature characteristics and the fact it's 20% thicker.  Be sure to allow a significant overlap of each turn.  It's also to best to wrap the tape up to connector, or the opposite way of intended water flow.  This is done to prevent the electrical tape from wicking water in.  You'll want to do this for each tape layer, if possible.  Also, on the last turn, don't pull the tape hard, just leave it loose and press it down.  This will help prevent it from unwrapping.
  2. Make sure there are no air cavities or openings in the tape!  Where there is air, there will be water.
  3. Next, wrap the entire connection once (or twice) with 3M Scotch 2242 rubber electrical tape.  Pull the tape so hard that it turns from black to gray, and wrap it tightly around the entire area previously covered with Super 88 electrical tape.
  4. Wrap the the entire connection once (or twice) again with a layer of Super 88 electrical tape, just like in step one.
  5. That's it!  A fully waterproof seal, with the ability to remove the tape layers using nothing but a utility knife.
  6. If you put CoaxSeal directly on a RF connector, I will hunt you down and shoot you.
  7. If you put CoaxSeal directly on a RF connector, I will hunt you down and shoot you.
  8. If you put CoaxSeal directly on a RF connector, I will hunt you down and shoot you.

It's often recommended that you spray clear-coat type sealants (Scotch-Kote) on your connection to make it waterproof.  This is O.K. to some extent, but not recommdended as an end-all solution.  These sealants contain acetone and other chemicals which can eat the rubber gaskets in N and Heliax connectors, along with the outer covering on some types of coax.  They also break down in ultraviolet light (sun light), the sealant will then flake off.  If you do need to use that type of sealant, for whatever reason, cover it with Super 88 electrical tape.

You can use spray clear-coat type sealants to waterproof non-critical connections, like to avoid dissimilar metal electrolysis, or in areas where it is just to hard to reach.  Be sure to check the connection at least once a year though.

If you do need to use CoaxSeal, please apply a layer of electrical tape to the area first.

RF connections are somewhat waterproof to begin with, but wrapping the connection will help prevent the connection from coming loose due to vibration.

If the connection will be underground, you may want to apply Plasti Dip spray-on coating over the final tape layers.

It is better to be cautious and waterproof your connections on the ground in the summer than to stand around like an idiot in January wondering why nothing works.

Return to Green Bay Professional Packet Radio for more info and contact information.