[CQ-Contest] RG-6 connector issues/ rcv array

[Tom Rauch]

> That used to be a big problem for cable tv companies that 
> used hardline with
> copper center conductors.  The coefficient of expansion of 
> the copper was
> more than the aluminum shield and the copper would pull 
> back out of the
> connectors when it got too cold.  Later designs of 
> hardlines used copper
> clad aluminum center conductors that apparently didn't 
> have that problem.


Different problem. That was a rigid jacket.
He described flexible cables with foil and woven shields, 
not solid extruded non-ribbed (unlike Heliax, which is 
ribbed) shields like those that created problems in the 
early CATV days.

Small cables usually have that "pull back" effect when they 
are physically stretched during or after installation. I run 
into that when I plow small cables with woven and foil 
shields into the ground if I don't watch tension, or if 
something tugs on the cable during or after it is installed. 
The center is a solid conductor that does not give, so the 
jacket and shield can easily pull at a different rate if the 
cable is stretched.

The cure is to always have loose slack at the ends, protect 
the cable from being pulled on, and after installing the 
cable if it is strained to let it relax for a few days 
before installing connectors. I use tens of thousands of 
feet of CommScope F6 and F11 style cables and unless the 
cable is strained I never have a problem. That's true 
despite hundreds of connectors in the system. If it is 
strained, like a cow gets caught on it or I pull it hard 
when installing,  I am almost assured of the problem.

73 Tom