Post by thread:EMI in my room 2 [OT]

> Your house wiring may certainly be run "open", creating large >inductive loops, but even if you had a power main running below the >house, it would not. There's a reason for this. Leakage inductance >represents major radiation losses to the power company - they are too >canny to allow that. I had a work colleague have to deal with management when they installed a customer training facility in the basement of a mainframe computer building. Immediately under the floor was the main power cables into the building. Every terminal monitor shook and hula danced until they moved the training facility somewhere else. another work colleague had to deal with a case where the picture on the monitor would go through a circular motion intermittently, and for no obvious reason. The picture would maintain its aspect ratio, and move around the screen in as though some ghost was playing with the centring controls. It would only ever do one complete circle when it occurred. It was eventually discovered that the wall behind the monitor was the lift shaft for the building, and the motion of the screen image was caused by the lift counterweight going past!!!!

Our IBM (ack!) 3270 terminal used to dance when the cables from the lift trailed past on the other side of the wall (in the lift well). Placing 2 monitors near each other will often cause interaction. . Russell McMahon _____________________________ - http://www.easttimor.com Updated regularly: 100,000 refugees STILL in West Timor face starvation! - http://www.sudan.com And you think Kosovo and Chechnya are bad! What can one man* do? Help the hungry at no cost to yourself! at http://www.thehungersite.com/ (* - or woman, child or internet enabled intelligent entity :-)) {Original Message removed}

Please remember to [OT] off-topic threads which are not directly related to the PIC microcontroller. Even if I'm interested I like to keep them separated. Thank You. Dan Terry wrote: {Quote hidden}> Andre, have you tried installing a new display card in your PC? > > Cheers > Terry > > At 04:24 PM 3/29/00 -0800, you wrote: > >> > This morning someone from water and power came by with > >> > a small handheld meter and we started to do measurements EMF all > >> > over the place. What I found is that near power transformer > >> > is 6,5 mg but close to my room (outside) is 15mg and inside of > >> > my room between 3,0 to 10mg. I also tried this I turned the microwave > >> > owen on and measured the EMF 10 inches far from the owen I got 15mg > >field. > >> > any help I will highly appreciated. > >> > > >> >Andre Abelian > > > >> > >> I assume 6,5 means 6.5? > > > >I checked it myself and I got the model number of that tool and a while ago > >I found the web site it is pretty accurate tool check it out > >http://www.meda.com/achand.htm > > > > > >> The readings you report don't seem to make sense.. > > > >I agree with you but unfortunately that is what I got > > > >>More field outside your > >> room, than near their power transformer? This would indicate something > >> generating a field within your house. > > > >The area where I got highest is right on top of my room comes from > >Power lines. > > > >> It could be a wiring problem > >It sounds like it but not in my house because I turned every thing off too > >I am still getting that signal. > > > > > >> You should follow the meter, keep moving twoard maximum flux, then try to > >> work out what is causing it. Be aware too, the probes need to be turned > >> through all three axes, to make sure you are seeing the real peak. > >> > >> If you had a loop of wire around your room, energized with 15mA of > >current, > >> that would give you 15mG. When you think in terms of possible leakage in > >> old wiring that isn't much at all. > >> I have this happening at home, though I haven't tried to run it down. > >> If you set your monitor scan rate as far as you can from 60Hz (70+?) then > >> you won't see it. > >Maximum I can go is 1024x1024 65hz I still can see it. > > > > > >Andre > > -- Daniel Hart Embedded System Design Engineer NBS Technologies, Inc. (Card Technology Corp.) 70 Eisenhower Drive, Paramus, NJ 07652, USA +1 201 845 7373 x183 spam_OUTdhartTakeThisOuTnbstech.com