[TowerTalk] Coax joint weather sealing

[Martin Sole]

Thought I would ask here to see if I can get some ideas for system 
upgrades.

Disclaimer: I am involved in a project professionally though I take a 
lot of this into my amateur radio activities and I'm sure others do 
likewise.

So I have been tasked to provide actual measured data from a lot of 
feeders where they terminate to antenna tails. Feeders are typically 
30-120m runs of AVA5-50, 6-50 and 7-50. Terminations are all DIN7-16 
typically to FSJ4-50.

Every outside connector has been sealed and for the most part there has 
been no moisture ingress or other failure in more than 90% of the 
feeders tested. One or two had a nice drip drip but I don't necessarily 
attribute it to the particular joint sealing.

My pain, and really it is a pain is the evil goo that resides with a 
joint. I believe the joints have been sealed with a 'traditional' method 
involving some thick butyl rubber compound directly on the connectors 
followed by a PVC tape over wrap. The local conditions see typically 
30-50 degrees C daytime temperatures and the joints were made maybe 7 
years ago.

In removing the PVC tape I am confronted by a sticky gooey oozing evil 
mess that sticks to everything and renders working on the joint a 
positive nightmare. There are no known gloves that can be used as the 
adhesive qualities of the evil goo pull even the most tightly stretched 
powdered gloves from fingers in a second.

I can't believe this is still being done and I'm sure there are better 
ways. For years I have wrapped connectors first in a couple of layers of 
plumbers PTFE thread sealing tape so that once the over wraps have been 
removed the PTFE tape comes away freely and leaves a nice clean 
connector joint.

Times Microwave has a youtube video showing some other methods. I've 
used cold shrink and its great, but pricey. The silicone tape and the 
crush together boots look like a winner as well.

https://www.youtube.com/watch?v=QHM5RkXD1is

Are there other good ways to make a decent weatherproof seal to a coax 
joint without having to encounter the black goo in a few years time? 
What's your favourite sealing method?

73
Martin, HS0ZED