[GreenKeys] UPPER and LOWER case

[WA5CAB--- via GreenKeys]

Electromagnetic shielding is shunt shielding.  Electro-static shielding is 
series shielding.

In a message dated 09/05/2015 01:36:41 AM Central Daylight Time, 
jdangus at att.net writes: 
> On 9/5/2015 1:19 AM, drlegendre . wrote:
> >WTH is "tempest" magnetic shielding? Being that you can't actually
> >/shield/ magnetic fields, the concept is even more dubious. 
> Tempest was the anal-retentive paranoid design engineering about keeping
> others from "listening in" by listening to the magnetic or electronic 
> pulses
> from machinery. When you're dealing with the spook agencies, you have a
> lot of money to play with, and the paranoia to justify it with.
> 
> And yes, actually you can shield magnetic fields using mu-metal.
> <https://en.wikipedia.org/wiki/Mu-metal>
> Most oscilloscopes have mu-metal shielding around the CRT to prevent
> stray magnetic fields (like the power transformer) from distorting the 
> trace.
> And commercially...
> <
> http://www.magnetic-shield.com/custom-mumetal-zero-gauss-chambers.html?gclid=CjwKEAjwgqWvBRC2kajZjqeOn0oSJADqBi-ldi-xsnLy-MwT7fjrTXMQeb06dl6zXgGmQPpy
> JIq8LBoCcG_w_wcB>
> 
> -- 
> Jeff-1.0
> wa6fwi
> http://www.foxsmercantile.com

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
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