FW: [Antennas] What is Beldfoil shield?

[David J. Ring, Jr.]

Feedlines in order of less noise pickup:

Single wire feedline
parallel wire feedline
coaxial feedline
parallel conductor coaxial feedline - I think this was called "twinplex" or 
something like that.
two coaxial feedlines in parallel

With the parallel feedlines one wire is fed in phase and the other is fed 
antiphase or 180 degrees out of phase.

73

David Ring
N1EA

----- Original Message ----- 
From: "Sam Morgan" <ka5oai at cox.net>
To: <antennas at mailman.qth.net>
Sent: Tuesday, September 05, 2006 8:24 AM
Subject: Re: FW: [Antennas] What is Beldfoil shield?


Eric Lemmon wrote:
> Sam,
>
> The answer is found in the glossary in the back of a Belden catalog:
> "BELDFOIL- A Belden trademark for a highly effective electrostatic shield 
> of
> reinforced metallic foil."  It comprises a very thin aluminum foil bonded 
> to
> polyester tape.  When properly applied, it provides 100% shielding.  Most
> Beldfoil-shield cables include a stranded bonding wire that is in 
> continuous
> contact with the aluminum foil.  Due to the possibility of 
> dissimilar-metal
> corrosion, Beldfoil-insulated cables should be used with caution in moist
> environments.
>
Well I guess the use of that cable outside is not the way to go. It doesn't 
rain
much here in Texas, but sometimes it does.

I have heard of running 2 coax lines in parallel to form a shielded 
feedline,
but I guess just a balun at the dipole feedline might just take care of the
thing I had read about unbalanced feedlines being more noisy? Or would it, 
or is
that even anything I need to address?
-- 
GB & 73's
KA5OAI
Sam Morgan
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