Coax question for the masses

[turbosat]

It's been a while since I saw this clue, and would like somebody to refresh me on it. Was updating a couple of old cable connectors outside today, before today's raincloud, and I cut off one old connector that looked suspicious. Cut back about 6" of cable and started stripping it for a new compression fitting, the aluminum braid inside was WHITE like snow. SO, I cut back another section, 12" or so and started stripping it, same thing! Is that water-damage, or lightning-related? The center conductor looked ok, but since this was not looking any better I chucked it all, and ran new cable. I'm thinking I saw that years ago after a nearby lightning strike, nothing looked burnt but looked like it was breaking down or affected by something. It HAS rained around here this summer, if anybody hasn't heard, lol. Some parts of North Ala have had 60" of rain, so far.

 

[markbone100]

The aluminum braid has oxidized, either from age or water ingress. Therefore that part of coax is junk

Same thing with the copper center. If there is any black on it, then water has gotten into it and that section is trashed. Since high freqs run on the outside skin of the center conductor, the black on it will attenuate/block some of the frequencies.

In those cases, its best to replace all of it if it isnt too hard. using rubber weatherboots on all outside connections, wrench tight connections, and fittings that have a nice seal at the coax helps a lot. and drip loops

 

[turbosat]

I noticed this coax, which I bought at Lowe's, has a date stamped on it, March 2009, so it isn't that old. Well, compared to direct-burial cable that was buried, I suppose. This was exposed though, to the air/sun from lnb to diseqc switch. At least it wasn't 150' of it, lol.

 

[markbone100]

From 2009 it shouldnt break down that fast unless it was super cheaply made, so im leaning more towards possibly water

 

[Anole]

It's too dry here for to get any experience using dilectric grease inside connectors before assembly.
Ask around and see what the guys say.

Next step would be to use that messy flooded direct burial cable.
?You wouldn't have to worry about it.

 

[mikelib]

Turbo,
I use this stuff on all of my Ham Radio coax. found it to be great for water proofing connections.

http://abrind.com/product/sealants/stufcable-connector-protection/

 

[turbosat]

Mikelib, I always use the coaxseal tape too, but I guess in this case I didn't use enough of it. Or maybe it wasn't applied correctly. I did see that I failed to include a good drip loop in that short run, something I usually do. You should've seen the piece I pulled off my copper J-pole today, that goes to my scanner on aircraft band. Same old white coax, but when I cut into it for a new connector, water came out. Cut another foot back-more water. Then two more feet>MORE WATER. I never saw anything like that before. Mostly due to this heavy heavy rain this summer, I'm re-doing a lot of outdoor connectors that I know are 2-3yrs old. No drip loop on that one either...lesson learned. Wonder what I'll find tomorrow.

 

[Lone Gunman]

Heh, and all I use are those cheapie screw on aluminum ends crammed full of Vaseline during assembly.

 

[gpflepsen]

I use silicone dielectric grease for my outdoor connections (available at your friendly GM dealer):



And when that little expensive tube runs out, I'll switch over to this big tube (any auto parts store should have it):

 

[Wescopc]

I have seen where a squirrel (on the roof) chewed a hole in the coax sheath and water went down 75 feet through a drip loop and into the tuner of the receiver - ruined the receiver. The white powder is from water. We get some rain in Oregon!
Bob

 

[markbone100]

Working for the cable co, I have seen splitters/ground blocks that actually were full of water from things like that too.

 

[turbosat]

After some searching around later last night, the consensus is water damage, and not lightning. I'll remember this mess , lol. I actually had half a spool of that nasty, sticky flooded cable, should have used it then. Just can't stand that stuff but I suppose it works.

 

[FaT Air]

Lightning, direct hit anyway, would have blown it apart, not just oxidized it.

 

[Anole]

Sticky flooded cable...
Harbor Freight, box of disposable rubber gloves.
They come in different colors/thicknesses and sizes.
?Around $6/100, on sale.
.
I keep my box in the car for changing tires and occasional crimes.
Also great for painting, staining, and handling glues.

 

[SatelliteAV]

Agree. Definitely caused by water. The coax braid acts like a wick and pulls the water through the coax.

I am also a big fan of dielectric silicone grease. A cap-full in each connector prevents corrosion and water infiltration. Easy to clean off with a shop rag during service calls.

 

[jorgek]

For long term, Coax Seal is a terrific product used by professional antenna riggers and installers of commercial communications systems. Costs about $3 for a 60 inch roll. It provides a long-lasting, waterproof seal for coaxial cable fittings. Its easily applied, stretches into place, sticks to itself and will not unravel like ordinary electrical tape. Its also non-conductive, non-contaminating, non-toxic, and UV-stable.

Additionaly I also use heat shrink tubing. A butane BBQ lighter will quickly shrink it into place.

Only draw back to both products is you have to cut it away to remove it. Its not intended for continual on/off cycles.

 

[markbone100]

I need some coax seal for some 50 ohm coax

 

[turbosat]

markbone the radio shack still had it last fall, when I last bought any, might check there if you have a store close by.
I went to the hardware store early today, but I must've been still asleep because the dielectric grease was one of the things I went to buy, lol. I'll hit the autozone Thursday for some.

 

[jorgek]

I need some coax seal for some 50 ohm coax

Plumbing sections in hardware stores (Home Depot) sell coax seal under different names and its sold as a repair for leaking pipes. Its will work on any coax 50 or 75 ohms.

 

[FaT Air]

Scotch 33 (All the others are junk IMB)
Wrap slightly stretching the tape - finish wrap without stretching.
Have had to do 'change outs' on TV antenna installs I did 15 years ago because of the 'digital conversion'. Had to cut it off with a knife. All have looked as good as the day I put it up there. No unraveling, no water infiltration, clean connector and conductors. (no dielectric grease either)