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Old 8th Sep 2017, 9:12 pm   #62
Radio Wrangler
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Default Re: SP / Sailor T128 problems - valve help please

Quote:
Originally Posted by crestavega View Post
matic at the bottom of the PDF.

[ the shack is conveniently a faraday cage
I just spotted this and thought I'd better comment.

A 'Faraday' cage is not an effective screen at all. It's a special one designed to let magnetic fields through and to stop only electric fields. This is a common confusion, but most people automatically prefix any mention of a screening cage with 'Faraday' and it completely reverses what they were probably intending to say.

Michael Faraday invented the screen named after him in order to demonstrate his invention, the transformer, and to counter the arguments that it worked by capacitive coupling. As far as keeping radio signals in, or out, Faraday cages leak like a sieve.

Faraday screens are commonly built into good quality transformers to prevent capacitive coupling of noise and interference between primary and secondaries without interfering with the magnetic operation.

David
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