[TowerTalk] Coax Seal yea or nay?

[K8RI]

On 5/19/2013 1:49 PM, Steve Sacco NN4X wrote:


> I strongly dislike Coax Seal, for all the reasons cited.

There are many reasons cited, but the have all been cosmetic.  IE: You 
can tell the connector has been used (so what) and it may or may not 
look like crap depending on the amount of coax seal left behind.

Myself, I don't normally use Coax Seal. I use flooded heat shrink, which 
has a layer of "hot melt glue" on the inside.  This adds a great deal of 
strength to UHF and particularly, "N" type connectors if extended onto 
the coax for about 2 or 3 inches.  The 3M heat shrink tube is fairly 
heavy strength. A splice of "N" type connectors will support my weight 
(over 170# back then) linearly.  Try that with just a normal weather 
proofed splice using coax seal, electrical, mastic, or the Silicone 
tape.  Those are all good weatherproofing, but add little strength.

Now if you don't like the looks of the hot melt glue residue, wipe on a 
very thin layer of silicone grease. Very thin and do not get it on the 
jacket. Nothing sticks to this stuff.  If you can see the grease there's 
too much. You only want a film!

To put it bluntly it can make adding coax seal a real bitch! Tape too. 
  With tape ( weather seal, mastic, or electrical)start the application 
back about 3 inches on the coax jacket and make sure it's stuck to the 
jacket. Don't let any of the grease get on your hands or tape, anywhere 
other than where it touches the connectors.

BTW it's not a good idea to hang "N: type connectors vertically without 
a loop at the connector.  The weight of the center conductor for a 100 
foot run up the tower will slowly pull down on the center pin of the 
connector until it may make a poor connection. Manufacturers warn about 
this some where deep in the info sheet where most are unlikely to ever 
see it.    This has caused many a difficult to find problem. In a run 
from the tower to a sloping dipole is another bad location for splices. 
Remember what strength those connectors are rated for. It ain't much!

But no one has answered my question.  Why don't many of you like coax 
seal?  If it's just because you don't like the looks then say so, but 
mechanically and electrically what does it hurt.?

Actually even in Steve's case, where it got "into" the connectors it's 
unlikely to hurt anything.

In some cases I've even filled connectors with DC-4 or DC-5 dielectric 
grease.  Other than being a lower viscosity there is little difference.
The one possible outcome in Steve's case would be preventing a good 
electrical connection because the stuff is tenacious. If the center pin 
makes full penetration it should still make a good electrical 
connection.  A TDR would tell for sure.
>

One last note. Unlike grease, the old motto: "The bigger the gob the 
better the job" does not hold true when weatherproofing.  A quality wrap 
is much better than a massive wrap.

OTOH I still don't understand why hams complain about coax seal sticking 
to the connectors. What does it hurt?

73

Roger  (K8RI)


> Last week, I unwrapped a connection which consisted of a bunch of
> PL-259's and right angle connectors which I had foolishly wrapped in
> Coax Seal, and overwrapped with Scotch 88.  It took a incredibly long
> time to get it off the connectors so I could even disconnect them.  I
> found that the the Coax Seal had worked its way INSIDE the PL-259's
> under the outer shell, in addition to covering everything with a sticky
> residue that I have yet to find something to cut it with.
>
> I've found the above problem repeatedly as I've modified things at my
> station that I did back when I was going through my Coax Seal phase.  I
> deeply regret that I went there back in the day.
>
> MUCH better are products like silicon Rescue Tape.   It fuses to itself,
> forms a tight seal over the connectors, and is easily removed.  You need
> to cover it with a quality electrical tape to protect  it from UV, but
> that's not unreasonable.
>
> 73,
> Steve
> NN4X
> EL98jh