Path: utzoo!attcan!uunet!jarthur!nntp-server.caltech.edu!tybalt.caltech.edu!chi
From: chi@tybalt.caltech.edu (delta chi)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Jitters with Two Screens
Summary: RF interference
Message-ID: <1990May31.031805.17163@laguna.ccsf.caltech.edu>
Date: 31 May 90 03:18:05 GMT
References: <3285@crystal9.UUCP>
Sender: chi@csvax.caltech.edu
Distribution: comp
Organization: California Institute of Technology, Pasadena
Lines: 34

In article <3285@crystal9.UUCP> derosa@motcid.UUCP (John DeRosa) writes:

>My problem is that the rgb monitor causes extreme jitter
>in the gray scale monitor.  This is confirmed by powering
>off the RGB monitor and verifying that the jitter disappears.
>We have reduced the problem somewhat by placing a aluminum rack
>panel between the monitors.  Most likely a grounded steel
>panel would fix it altogether but that is not the point.
>
>The point is, what is wrong that causes this problem in the
>first place?  The repair techs say that everything is ok on
>the monitors.

Everything is in fact quite normal.  Nearly all (I am tempted
to say ALL, but I know someone is going to say, ``But what about
the Yoyodyne Model X?'') display monitors are serious emitters of
radiofrequencies from the sides and the rear.  RGB displays are
particularly evil in this regard.

For the same reason (no real shielding on the sides) RF interferes with
an adjacent display.  Putting the aluminum rack panel between the two
monitors provides some shielding.


The real moral of the story is: ALWAYS sit in front of the monitor.  I'm
definitely not of the alarmist school of thought, but there is
increasing evidence that extended exposure to the radiation from the
sides of the monitor is not a good thing.

---
...!ames!elroy!cit-vax!chi       Curt Hagenlocher       chi@cit-vax.caltech.edu
"You can't tell me anything about South Africa, Mozambique, Angola, or
 anywhere and make me believe you're sincere as long as you keep quiet
 about what the United States is doing to us in that country." -- Malcom X