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In response to a question about how to place EMI RFI blocking materials on another site:
I wrote,
""First thing pops to mind is getting an RFI EMI detector.
I have a nice one "non contact voltage detector" GreenLee GT-16 from Amazon cost is $22 or so.
It can detect the RFI mainly from AC cables and wall outlets. Digital connections.. But also can beep at any AC type radiation, music signals leaking out of cables too, and small panel displays.
You can find where all the bad stuff is leaking out. Really! And you can find out if your shelves already block it, or, allow it to spread! (some stuff just lets it move around. The source fills up the whatever you are using to block it..then when that is filled up (because you did not ground it.. yes to AC wall ground.) THAT starts being a radiant source of EMI RFI.
REALLY!
The GreenLee is a nice design. I bought others which just no way as nice.
Worth the $22 to play with.
Got me to start using small baggies of coated quartz crystals (they STOP the RFI in its tracks without having to be grounded. The quartz turns the RFI into heat/vibration. (if treated with a non-conductive grease, and pressed flat so no air gaps. Work great on AC plugs..)
With the non contact AC voltage detector... you can FIND the big culprits. Instead of just guessing.
My worst offender was my tubed VAC Standard (separate) power supply umbilical. I had to wrap it with conductive foam them ground the foam to the AC wall ground. Very effective.
I think it was so bad due to the tube supply voltages in the unshielded umbilical) ""
Enjoy.
Follow Ups:
Elizabeth, where did you get the conductive foam from? I have an Aesthetix IO with two umbilicals that would beneifit from this. Scott
Pemro .com has all sorts of sheets of antistatic black foam.
I bought 3 39" by 39" qnd 3/8" thick. $80 or so. The issue was it took them over three months to send them. i had totally given up they would ever send the foam and one day there it is at my door in GIANT box.
Sad I did not order enough.. So sooner or later i may order more.
They have many many variations in size and thickness of black antistatic foam..The variety has dropped but her e is a good sample listing:
Edits: 03/09/14
But for tracing down RFI/EMI it's not going to help much.
From the GreenLee website Frequency : 50 - 500 HZ
It blew out a good chunk of the building lighting.
He thought it was funny until he got fired.
One of the screwdrivers was melted clean through..
Probably a 20 amp outlet.
Anybody see the Crown amp demo where they do the same thing with a very low Imp. load played very loud & the amp just snaps back on?
Lucky guy - most times he would have been toast also....
I agree it is not finding sources in the higher Hz ranges. So what? The main crap we have IS the AC stuff. Maybe if you have a shortwave rig you can use another tool...
but what is the frequency range of EMI? I assume it is much lower than RFI, but is it all below 500Hz?
I have one, works well. I found a lot of "noise" around one of my speaker terminals - turned out to be from a lamp that wasn't even that close to the speaker. Moved the lamp wire around and got rid of the noise. Still baffled as to why but it worked.
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