I believe that once water has penetrated the outer covering of FSJ cables, they
are more prone to wicking the water into the inner insulation and conductor.
They have a spiral outer conductor, which means there is a spiral join all
along the copper which can allow water inside; unlike LDF types which have a
continuous corrugated outer conductor, which therefore has no join for water to
enter (except at the connector). So any slight damage to the outer of FSJ
(which may not be easily visible) will allow water ingress right through to the
inner. Doesn't mean FSJ cannot be used outside, but it is more risky as
abrasion or cut of the outer coating will likely let water in to an extent that
deteriorates the cable's performance.
Net: Jim, your buddy with lots of FSJ outside is going to see more water
ingress problems...
73, David G3WGN M6O
-----Original Message-----
It's quite possible that only the outer jacket has been damaged, somewhere up
the tower, but not the solid copper shield. This would allow water to run down
between the jacket and the shield, ending up inside the connector, but the main
length of cable coming down the tower may still be electrically OK.
A quick-and-dirty fix to allow the water to drain away is to cut away a few
inches of the jacket near the lower end of the cable (like ring-barking a
tree). At the bottom end of the cutaway section, make a new water seal by
taping the jacket tightly onto the exposed copper shield, but leave the top end
of the cutaway section free to drain. It isn't pretty but it would keep you
going until the better weather.
73 from Ian GM3SEK
>-----Original Message-----
>From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
>Peter Voelpel
>Sent: 16 January 2016 15:39
>To: 'Jim Thomson'
>Cc: towertalk@contesting.com
>Subject: Re: [TowerTalk] Andrew FSJ4-50 issues
>
>Hi Jim,
>
>Never heard about the cable not being for outdoor use.
>It is essential to fill the body of the plugs with silicone grease to
>prevent the accumulation of condensed water.
>Connectors may not be left unprotected from the weather even for one
>day.
>I use that stuff across my rotators together with a few CF12-50 cables.
>Main feed lines are LCF78-50 or RG218.
>In total 13 such cables are turned on my 4 towers, 8x LCF12-50, 5x
FSJ4-50.
>
>73
>Peter, DJ7WW
>
>
>-----Original Message-----
>From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
>Jim Thomson
>Sent: Samstag, 16. Januar 2016 14:57
>To: towertalk@contesting.com
>Subject: [TowerTalk] Andrew FSJ4-50 issues
>
>A buddy is having issues with his Andrew FSJ4-50 flexible coax.
It's
>being used on a rotating tower.
>He used FSJ4-50 from each yagi to the tower, then spliced ( via a
male to
>female 7-16 din) into
>more FSJ4-50 heading down the tower. At the bottom of the rotating
>tower is the remote switch box.
>On the 40m coax connector, at the remote switch box, there is water
>coming
>out of it ! The splice
>was encased in heat shrink, with the glue glop inside. Also at each
>balun.
>
>We think the cable coming down the tower is toast. Is this FSJ4-50
>intended to be used outdoors ??
>I looked at some old postings from 2006, and it appears that FSJ4-50
was
>to
>be used indoors only, for
>jumpers etc. The other postings indicated it did not have any UV
protection
>on the outer jacket.
>
>I THINK I also read somewhere a long time ago that FSJ4-50 was prone
to
>water ingress.
>
>Does anybody know the real story on this stuff ? It can be replaced
with
>the rigid andrew 1/2
>inch regular heliax. It doesn't have to flex for this
application....on a
>rotating tower. At the base
>of the tower, where the remote switch box is, there is a single,
flexible
>piece of coax, used
>for rotating the tower, like 213-U...then the 213-U is spliced into
more
>(normal rigid) 1/2 inch heliax,
>and off to the shack area.
>
>The concern here is... if FSJ4-50 is pone to water ingress, then he may
well
>be in for more problems,
>since all the coax runs down the tower are also FSJ4-50
>
>Thanks in advance.... Jim VE7RF
>_______________________________________________
>
>
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