[TowerTalk] Coax ground braid

[Mickey Baker]

I worked at The Phone Company many years and saw lots of wet cable, from paper wrapped copper in lead to modern composite jacket fiber.

There are a wide variety of things that could've damaged your cable. UV and temperature changes, rodents, birds, insects, reptiles, bullets/shot, darts and wind, to name a few. The older rubber/vinyl cables were notorious for developing holes. 

Someone offered me a 4' spool of CATV hard line this past weekend for free. I pulled the end, gave it a twist and the jacket crumbled off in my hand.  

My friend, ever the optimist, said, "It's not all like that." 

That made me hesitate and look at this big spool of huge coax... I asked my friend, "Tell me how we can, very reliably and easily determine the good from the bad."  As my friend rambled on about his TDR gadget, I started to rotate the spool to try to find specs or a date, the wooden spool came apart with the loud wet crackle familiar to those have heard wooden things break.

We decided to pass.

Mickey  N4MB

On Apr 16, 2012, at 6:54 PM, Bob Ad5vj <ad5vj at ad5vj.com> wrote:

> So it is water damage. 
> 
> When I make up my coaxes, I always solder all the holes at the pl-259 and seal it with coax selfsealing tape and adhesive lined doublewalled heatshrink. So no water got in at the connectors I dont think.
> 
> This coax was given to me on a roll 500' long to make 2 80 meter bazookas. He said the roll was found some years before and kept in a shed and I could keep the rest. So the water damage must have been there all along.
> 
> Free is not always free.
> 
> I will remake the station grounds, even though I spent all afternoon taking the station apart and cutting out the braids to make sure it was right.
> 
> I was always told to use flat braid for station grounds in years past for RF purposes and if you didnt have any, make it from coax braid.
> 
> Guess W3LPL has found out different.
> 
> 
> tnx Bob AD5VJ
> 
> 
> Sent from my Samsung Epic™ 4G
> 
> Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
> On 4/16/2012 11:08 AM, Bob Ad5vj wrote:
>> In doing so, after removing the outer jacket I see places where the copper is black in some areas. Some places as much as a foot long.
>> 
>> 1. Will this hurt the conductivity as a ground braid assuning I clean it up where I make contact from the equipment?
> 
> YES -- that's corrosion, and it can greatly reduce the conductivity of 
> the braid.
> 
>> 
>> 2. Has anyone seen this before?
> 
> Sure. it means your coax has gotten wet.
> 
>> 
>> 3. Does this mean I need to changeout all my 3yr old coax outside which came off the same roll at the same time?
> 
> If it all looks like that, YES.  I'd do some more inspection first.  
> Water gets into coax either at connectors, or at tiny breaks in the 
> outer jacket, look for damage and for poor waterproofing.
> 
> And I would be a lot more careful with what  I bought to replace it, and 
> I'd also be VERY careful about proper installation of connectors, and of 
> waterproofing all the connections.
> 73, Jim K9YC
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