[TowerTalk] Coax joint weather sealing

[john at kk9a.com]

I do not believe that putting butyl directly on the connector is the  
traditional method, at least I hope not! I have purchased a few used  
LFD7 connectors where this was done and cleaning it was a horrible  
job. Nothing seems to clean this mess. These days I only buy new  
connectors.  You are supposed to first apply black PVC tape, then  
butyl rubber and then more black PVC tape. Of course the black tape  
glue still leaves a mess on the connector however it is nothing like  
the butyl mess and it does not effect the connection when  
reassembling. Commscope has instructions for using their kits, which  
BTW are great:  
https://www.commscope.com/catalog/doc/pdf/2004/Weatherproofing_Kit_for_Connectors_and_Antennas.pdf

The PTFE tape is an interesting approach, some people do a backward  
lap of PVC tape too but I guess I feel better when tape is actually  
sticking to the connector.

John KK9A


Martin Sole hs0zed wrote:

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