Topband: "Is your feedline also an antenna?"]]

Tom Rauch w8ji at contesting.com
Sat Oct 8 15:05:40 EDT 2005


> > Unfortunately this doesn't apply at all to HF receiving.
It
> > only means something at 60 Hz, where it affects video.
>
> Tom, For the purpose of dealing with signal ingress, would
not the Faraday
> Shield cure work on 1.8Khz as it does at 60 hz?

I think you mean 1.8 MHz Herb, in which the answer is no.
While the physics is the same, the frequency is vastly
different. The scale of what we are looking at is off by a
factor of 1,800,000/60 or 30,000 times. If shield thickness
is .02 inches on 1.8MHz, the 60 Hz shield would have to be
600 inches thick.

If a quad shielded cable had a 2400 inch thick shield a 600
inch thick shield wall would be just as effective at 60 Hz
as far as we would be concerned.

This is why audio and video systems behave much different
than our RF cables when it comes to grounding and ground
loops, shield quality and thickness, and so on.

73 Tom



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