Here's the method we used in the Navy/Coast Guard to weatherproof
shipboard connectors. I don't think you can find a worse environment
than salt spray driven by gale force winds!
First, wrap the connector with the self vulcanizing tape. This tape
is stretchy and conforms to the connector avoiding air pockets. It
will stick to itself but only lightly to the connector. As this tape
degrades under ultraviolet, it must be covered with a wrap of vinyl
tape. Finally, the whole thing is covered with some type of coating.
We used Scotchcoat but others might be more available. This final
coating seals up any gaps in the vinyl tape and keeps the end from
Also, if done properly, a dab of silicone grease in the connector
prior to mating adds extra insurance. The best thing to use is the
little packets with a nozzle such as comes with Andrew connectors.
If you try to use a regular tube of grease, it will usually get on
the outside of the connector and the tape will not stick!
Believe me, this method has stood up to everything the North Atlantic
could throw at it. And when it comes time to test the antenna, the
whole thing peels off cleanly after being slit with a knife.