I'll bite, as well..
Double shielding might provide a more consistent cable propagation
characteristic as the cable flexes.
Double shielding might help (if properly (however that might be) to separate
the "coaxial transmission line outer conductor" from the "shield" (that is,
it's a shield around a coaxial cable).
If you expected to take ESD or other discharges to the outer shield and
didn't want the terminating load to have to suck up the energy. The outer
shield performs the function of the "green wire" safety ground, the inner
shield is the RF return.
In expensive houses being wired for cable TV.. quad shielded just has to be
better than triple or double shielded, and since labor is the dominant cost,
why not install it,because your competitors are.
(I'm waiting for the alarm/cable TV/residential network installers to give
traceable certificates on test equipment for their installations... "what do
you mean Cat 5 has a legal meaning? You mean I need to test the cables
after I pull them, and I can't just staple them to the studs?" Don't get me
----- Original Message -----
From: "Tom Rauch" <firstname.lastname@example.org>
To: "Steve Katz" <email@example.com>
Sent: Tuesday, October 12, 2004 5:01 PM
Subject: [TowerTalk] Shields
> Re: Double shielding, usually it's not important at all.
> However, there are
> > applications where single shielded cables hardly work,
> unless the shielding
> > is solid, like hardline. One such application is in a
> duplex repeater
> > system. Another might be when your station is located
> close to a high
> > powered broadcast station. -WB2WIK/6
> OK, now I'm on the same page (except for the repeaters,
> because most duplexers have far less notch depth than you'd
> ever have crosstalk through shields).
> I agree now with the general concept. When you are doing
> critical measurements in a screen room, you need exceptional
> For a system connected to an antenna, you are wasting money
> if you go out of the way to buy double shield. That agrees
> with everything I've experienced.
> 73 Tom
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> TowerTalk mailing list
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
TowerTalk mailing list