[TowerTalk] Coax joint weather sealing

[Les Kalmus]

I have done many of these without any water ingress or removal problems 
by first wrapping with black PVC tape with the adhesive out. Then a PVC 
wrap with the adhesive in and then a butyl tape wrap and finally a PVC 
wrap over all. In every wrap each turn overlays the previous turn by 
half of the tape width and the overall length of the wrap extends beyond 
the length of the underlying wrap. Each wrap runs in the reverse 
direction of the previous one. Fifteen years later there were no water 
or removal issues.

Les W2LK


On 5/28/2019 3:03 PM, john at kk9a.com wrote:
> 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
>
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