[TowerTalk] Shields

[Keith Dutson]

Perhaps we are not concerned about shielding at all but just want the lowest
loss cable available, and it is shielded this way.

Keith NM5G

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Tom Rauch
Sent: Tuesday, October 12, 2004 9:57 PM
To: Daron J. Wilson; TowerTalk at contesting.com
Subject: Re: [TowerTalk] Shields

> I'm sure you know the difference between balanced and
unbalanced
> feedlines.
>
> But..if the shield is no matter, how about taking that
RG8X and
> stripping all that unneeded copper braid off completely?
I'm guessing
> the manufacturers of coax sell a LOT more of the stuff
with a braid on
> it, and I'm still pretty sure there is a reason for it.

The point is if currents are equal and opposite and conductors are close, a
line certainly doesn't radiate very much.

The vast majority of problems at HF are caused by unequal currents entering
and exiting the center and shield at each end.

It's ironic to see how much we worry about insignificant issues, while
pooing real problems. I'd wager the bulk of people who think multiple
shields do something meaningful also think a groundplane with four radials
can be fed with coax without significant common mode currents appearing on
the feedline.

Anyway enough of this. It's cutting into my Star Trek time.
I need to see some real shields in action.

73 Tom


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