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Re: [TowerTalk] Shields

To: "Jim Lux" <jimlux@earthlink.net>,"Daron J. Wilson" <daron@wilson.org>
Subject: Re: [TowerTalk] Shields
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Wed, 13 Oct 2004 06:41:22 -0400
List-post: <mailto:towertalk@contesting.com>
> Except that the shield is woven, so the conductors
"penetrate the shielding
> plane", and can carry energy from inside to outside. All
bets are off on
> small apertures with woven shielding.

Actually it's pretty good when the shield wires are
compressed by the jacket and clean.
That's why moisture or anything else that increases
resistance of those hundreds of pressure connections kills
the RF performance of braiding. It's just about like copper
screening.

Jim Brown made a good point.

>FWIW -- lots of the high futility folks use double shields
and quad shielded cable because
>they are trying to make RF cable do double duty for
baseband video, and the quad shield
>simply provides lower resistance (and thus lower loss) at
low frequencies. And often they
>don't KNOW why these cables work better, but that's why. :)

The theory I heard is if you let your signal get too
comfortable in a nice cable, it'll never leave home.
 That's why I use RG8X jumpers, even for high power.

73 Tom


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