Stuart,
I've been considering fabricating a copper box to enclose
the monitor. However, coming up with a suitable screen
material for the monitor front has been an issue. A piece
of scrap 14X18 copper mesh was tried but it tends to
obstruct the detail too much. Any suggestions for a larger
mesh size that would be an effective shield and yet be able
to see through?
Greg, K7KJ
Portland, OR
----- Original Message -----
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
To: "Sherrill WATKINS" <SEWATKINS@dgs.state.va.us>; <tentec@contesting.com>;
<justo@maplenet.net>
Sent: Tuesday, May 15, 2001 1:22 PM
Subject: Re: [TenTec] Computer EMI - Brand?
>
> Corn,
> Sad to say, most the EMI we have measured in the lab from these CRTs is
> coming thru the screen glass! There are some mesh screen covers that
> attenuate some of it, but shielding of the case and leads is a good idea
as
> well. But, it is an artifact of the high voltage deflection against the
> phosphors that sprays EMI out the front, and not much other than distance
> from the radio will help it.
>
> We actually decoded what was on the computer screen as a visual pattern by
> picking up the RF a room away and applying it to a high frequency lab
> oscilloscope.
> Of course, the sync lack caused the picture to continuously roll, but you
> could make out what the characters on the CRT had been.
>
> The replacement of vacuum CRT technology with LCD matrix or other flat
> screen types hopefully will ban this EMI source.
> 73,
> Stuart K5KVH
>
>
>
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>
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