Hmm here's an experiment...

Playing with basic SW radio as I'm in a metal-framed building so normal stations are hard to come by. Ok no problem, I can try to explore what I can i.e what electrical noise there is. Near the SETI farm I'm noticing non-natural noises, & can confirm whether these are related to machines @ 100% or not via snoozing/resuming computation & seeing how the sound over the radio changes. Laptop indeed singled out around 2.29MHz with a nice wooooooooooooop-fx as I resume :D!!! Lpatop off so that's out the equation now, trying to find the other machines...

(Anyone know what freq an Athlon64 X2 transmits its RF noise on? ;))

(Make that 15.41MHz...)

Dave,
If your hearing something on a short wave radio near your computer, its nothing to do with whether SETI@home work units are running on the machine. SETI@home work units will not be transmitting anything inside your PC.

Maybe your hearing some general static, something related to the electronics in the PC. But its very unlikely unless you have modified your PC or added hand-made hardware. Most computer manufacturers go to great lengths to shield the EM radiation in your PC.

Computer processor chips don't emit any RF noise! Also the metal box surrounding your PC is grounded to Earth to prevent RF noise. Your could point the Arecibo radio dish at your PC and it wouldn't hear a thing.

John.

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Dave,
If your hearing something on a short wave radio near your computer, its nothing to do with whether SETI@home work units are running on the machine. SETI@home work units will not be transmitting anything inside your PC.

Maybe your hearing some general static, something related to the electronics in the PC. But its very unlikely unless you have modified your PC or added hand-made hardware. Most computer manufacturers go to great lengths to shield the EM radiation in your PC.

Computer processor chips don't emit any RF noise! Also the metal box surrounding your PC is grounded to Earth to prevent RF noise. Your could point the Arecibo radio dish at your PC and it wouldn't hear a thing.

John.

Sadly not true. Computers are one of the worst sources of radio frequency interference. That is why governments demand they be shielded. As CPU speeds have picked up they have shifted from shortwave into microwaves, but they radiate across the entire spectrum. The nasty deed made all the worse because they switch using square waves not sine waves. Square waves toss harmonics like mad.

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It's just interesting fx, & definitely linked to the client/CPU due to the sonic effects of the CPU revving up & down :). I'm not trying to claim to have found anything to change the destiny of humanity...

The noise is most discoverable from the laptop. Also an old non-PC machine chucks noise all over the place. Both these machines visibly lack the internal metal shielding that the Dells have quite clearily in abundance.

I have a radio near my computer. When using AM I hear a noise which is stronger in summer when the computer fans speed up than in winter. But FM is not disturbed in any way. My CPU has a 1.8 GHz frequency.
Tullio

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as an more or less experienced numbers stations-hunter (secret sw-transmissions) i can confirm, that computers made noise too. especially it's not the computer "itself"; take a laptop, plug it to your radio, listen to it and THEN unplug the power cable of your laptop and voila - silence! (using the sangean ats 909 with an macbook pro)

How are you plugging the laptop into the radio?

with an two-way-cable like this one http://piraten.in/4hd - just plug it into audio-in on your book and the audio-out of your radio :)