-EMI Problems-

[epion2985]

I want to buid a case out of plexi but I have been told it will emit an insame amount of EMI. As well as it will not be shelded against it.

now first what is emi?
how does it work?
how to combat it in my situation?

[Krusty]

emi is electromagnetic interference.

When electricity runs through a wire, it creates a magnetic field radiating outward from it.

I have never heard of people having problems with their computers interfering with other devices because of emi. I think the purpose of the metal case is to prevent emi from messing with your computer system. Desk fans, monitors, television, stereos, etc could create interference that could mess with your computer.

You should ask in the alternative modding forum if anyone has had problems with plexi cases. There are plenty of them out there and people still continue to make them, so emi can't be that bad.

One way to help reduce emi is to get some ferrites. Ferrites are rings of a somewhat metallic substance that kinda have the same appearance of magnets. Any wires running through your system should have some ferrites on them. This will help reduce emi emitting from any wires in your computer.

I believe this (http://www.mpja.com/directview.asp?product=12406+FL) is a little example of what a ferrite is. Generally, one or two of these is included when you buy a new computer case.

[DaveSauce]

emi isn't a problem at all...at least not in my experience.

My case window is facing my monitor, and I've never had problems wiht it.....and its an 1/8" acryllic window, so absolutely no EMI shielding whatsoever.

The only problem you may have is if your fans get too close to a monitor or TV. I don't think computer fans are powerful enough, but I have a little 120v AC desk fan that I have to use on the floor, because if I put it on my desk and turn it on it messes with the monitor...I don't know if case fans get enough current to do that though.

[Tecumseh]

EMI can be a problem if you leave the case cover off a conventional
PC or if you have a window or entire plastic case.

The real question is if it makes any difference. IF it doesn't
get in your (or your neighbor's) TV, RADIO, garage door,
cordless phone or other RF equipment, then it seems
that it just doesn't matter. The FCC takes a dim view
of this, however.

[epion2985]

haha, I am an idiot! emi, its rf basicaly, what the hell was I thinking *smaks himself with a heavy book* ....god this is ridiculous, I am majoring in enegearing and know that and more. Dont you hate it when you know somehting but you dont think and you think you dont. haha, made such an idiot of myself ^^

anywho, yeah, I know how to deal with it. At that radar station at loki (not sure how to spell that) they had to put in aluminum fail in to the walls because int he cold war the soviets could detect the rf eminating from everyhting, including every time someone hit a key ont he keyboard, funny ^^ but yeah, aluminum foil...erm... to tedious. There are rf shilding paints, so I'll just spray paint it on the inside. Thanx for the help anyway.

[Krusty]

Originally posted by epion2985
anywho, yeah, I know how to deal with it. At that radar station at loki (not sure how to spell that) they had to put in aluminum fail in to the walls because int he cold war the soviets could detect the rf eminating from everyhting, including every time someone hit a key ont he keyboard, funny ^^ but yeah, aluminum foil...erm... to tedious. There are rf shilding paints, so I'll just spray paint it on the inside. Thanx for the help anyway.

Umm...I believe aluminum foil or rf shielding paints would . . . uhh . . . make your pretty acrylic case no longer clear.

If you were going to go the way of shielding your acrylic case, try to find out just how much metal will shield it. Some chicken wire stuff with the wiring like 1/2" apart might be enough to shield it. Then the case would still be clear --it would just have mesh visible.

[epion2985]

haha guess you havent read my post on the case I will be making. It will be painted black from the inside, so from the outside it will have a black mirror polish ^^

so I was gaoing to paint the inside black first, then the rf shielding paint.