Mailing List Archive

Support open source code!


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: tlug: shielding from high EM interference



Scott Stone <sstone@example.com> wrote:
> 
> one of the support pillars in our office here (structural support) has the
> main power conduit for the building running through it.  Not usually a
> problem, but any monitor placed anywhere near it will flicker and 'waver'
> very badly from the EM interference, or so it seems.  Is there any kind of
> material we can buy to shield against this?

It's the _magnetic_ field. And low-frequency. Very tough. You need either
_lots_ of the best conductor you can get[1] or some ferromagnetic material.
For the latter, probably the best bet is the sheet metal used in
transformators (plain cast iron?)[2].

[1] Sorry, I don't have the conductivity of copper at hand. But if you use
    something non-ferromagnetic with the conductivity of iron, you get
    a skin depth of 3cm. Obviously a purely academic solution ;)
[2] 2mm of iron. Skin depth should be about 1mm.

I hope I did the math correctly. No guarantee.

-Klaus

PS: A few years ago I visited CERN. As you may know, they have extraordinary
strong _stationary_ magnetic fields. Nothing to do about that.
You had to read the text on the monitors from the lower left corner to the
upper right corner.
----------------------------------------------------------------
Next Technical Meeting: 12 December, 12:30 *** place TBA ***
IMPORTANT: TLUG is looking for a venue for the next meeting
if you could host in your university or office, please contact us
Next Nomikai: 15 January 1999, 19:30 Tengu TokyoEkiMae 03-3275-3691
----------------------------------------------------------------
more info: http://tlug.linux.or.jp Sponsors: PHT, HSBC Securities


Home | Main Index | Thread Index

Home Page Mailing List Linux and Japan TLUG Members Links