Computer noise on 500kHz

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Joined: 2009/01/23 - 19:45
Computer noise on 500kHz

Having identified most of the sources of RF noise in the house that interfere on 500kHz, I'm down to one I can't just switch off. My computer makes enough noise to drown out signals.
I'd been wondering about this, as the direction of my loop for best sigs is the same for all stations. In fact what I was doing was not peaking the desired sig, rather I was nulling the QRM and improving the S:N ratio.

Switching the PC off (its not the monitor) removes about 9 S points of noise !

This PC is fine for all other bands noise wise. I have ferrites on pretty much everything, earthed case etc. Digital modes run well on other bands, and I can run QRO without problems either to or from the PC.

Only 500 kHz (and 137) are problems.

Any brilliant (or even semi-brilliant) suggestions? Pretty hard to do wspr by ear!