[TowerTalk] Possible rain soaked coax

Roger (K8RI) K8RI-on-TowerTalk at tm.net
Sun Dec 30 14:46:39 EST 2007

> Fellow (and lady) hams:
> In installing new more energy efficient windows at our
> home QTH in North Texas we had to remove the old
> window feed through (made by now out of business
> Lambda-Vector Company)and the cables were left
> outside, yes I forgot to seal them in plastic or
> something else.  Two runs of RG213 and one of 9913.

I'm going to make an assumption, which is never safe, that as this is the 
bottom end of the coax it is also the lowest point, or there are only a few 
feet that are low. As the lower end is open and I assume the top is well 
sealed the coax will breathe with both temperature and pressure changes and 
braid will "wick" moisture up hill a bit. 9913 ia like a hose inside, but 
that is good in this case as air can flow freely and there is less tendency 
for wicking except for the spiral direlect contact points with the inner 
concuctor and the outer dielectric sleeve.

The *odds* are you probably do have moisture in the first couple of feet due 
to your climate, but if there is little laying on the ground (it goes 
up-hill right after going out the window it is unlikely the moisture will 
have made it very far up the coax. No guarantees though.

About the only real check is to cut off the connectors and check the inner 
and outer conductors. Three months should have been long enough for any 
damage to be visible except possibly for the moisture that has made it the 

My guess and I emphasize  "guess" is it is unlikely the damage (if there is 
any in any individual piece of coax) will not extend more than a foot or 
two, but nature can be persistent and sometimes a bit surprising.

First, cut off the connector and check both the center conductor and braid. 
If you find moisture or visible damage, cut back to where you find no 
damage, or moisture and then take at least another foot or two off the coax 
which *should* leave the rest in good shape.  If you see no visible damage 
and do not find moisture, I'd still cut back another foot from the 
connector.  If necessary make the coax still reach, make a good quality 
splice and waterproof throughly using either the tape and coax seal method 
or the flooded heat shrink tubing approach. With good connectors there is 
little added loss and they are far cheaper than replacing with new coax 
although LMR-400 is available at some prettty good prices. However even at 
near 60 cents a foot you don't get many feet of coax for the cost of the 
three connectors required to make a splice.

Good Luck,

Roger (K8RI)

> Any hope of saving them such as cutting off several
> feet at the former PL259 that led inside, or should I
> scrap the whole thing and just spent the $$$ for new
> RG213 and a run of LMR400?  I hope to save some of the
> 213 and 9913 to use for
> Yes I messed up (40 lashes will be administered with a
> wet piece of 9913), but things were hectic around here
> with the window company. The windows were installed
> back in October and we're still fighting with the
> window company to correct things such as scratches on
> the painted frames, the kitchen window was installed
> crooked, the edges of several windows look like
> someone took a hammer to them and are so burred up
> that my XYL Cheryl (WY5H) actually cut her hand trying
> to raise one.
> I've since bought an MFJ window feed through (sure
> wish they had more than 3 SO239s feed throughs
> installed, maybe 5 or so)since I'm not a fan of twin
> lead (oh boy that'll start a discussion I know)and
> just waiting for the windows to be fixed before
> finally getting everything in order.
> I don't want the window company somehow blaming my
> coax installation for all of the window problems.
> Now whenever I want to make a QSO I raise the window a
> few inches and run a new short piece of coax out to
> the old and use a barrel connector to tie them
> together.
> Tom, WW5L
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