[mythtv-users] quality shielded coax cable

[Brian Wood]

On Jul 3, 2006, at 10:31 AM, Greg Woods wrote:

> Is that an oxymoron, or is there a place (brick-and-mortar or web)  
> that
> is good to look for this? I'm betting the answer isn't "Radio  
> Shack" :-)
>

As opposed to "un-shielded" coax cable :-))

Not sure what type of cable you want, you don't say.

Because it really depends on what you want to do, a 75-ohm coax  
designed for video (Belden 88281) does not do so good a job for  
passing RF energy to 3Ghz., and a wire designed to hang in the air  
from the pole to your house won't spool onto a reel very easily.

Cables designed for RF transmission are generally 50-52 ohm  
impedance, RG-214U is great but costs about $6/foot.

RF cables also come in single, dual, triple and even quad shield, for  
varying resistance to outside ingress and radiation from the cable.

Canaire makes some cables designed especially to be flexible and take  
a lot of spooling and un-spooling, a favorite on TV remotes, although  
the stranded center conductors are a pain.

Copper or Aluminum shields have different purposes. Times even makes  
one with a 90% silver center conductor and 100% copper double shield  
(hand *that* reel to a cable installer used to aluminum's weight :-))

  Belden makes good cables, Times Wire and Cable (AKA Times Fiber)  
does as well.

The normal communications and electronics supply outlets sell them  
both, Newark Electronics, MCM etc. Pacific Radio in L.A. has always  
had good prices (ever since they bought about 1000-miles of Belden  
cable for the LA Olympics back in the 80's).

Essentially the old maxim applies - you get what you pay for, and the  
good suppliers make the specs easily available.

It's also important that you use connectors designed for precisely  
the cable you are using, the best cable in the world will perform  
poorly if it has a 10-cent connector on it that has been crimped with  
a pair of pliers, or not crimped at all. It takes skill to properly  
solder a BNC connector or a PL-259, but if done correctly it will  
work great forever.

If you have a specific purpose in mind let me know and I'll make a  
suggestion or two, gratis and worth every penny :-)