[linux-audio-user] Radio Interference problems when recording

This is a bit OT, but since I do all my recording on Linux machines, I thought I'd see if anyone on the list can help... I used to do all my recording in a basement, but since we've moved I got a new computer setup in our finished attic. 64studio is loaded on it (and works GREAT out of the box on my HP Athlon 64), and everything was working tickety-boo, audio running in and out of my M-Audio 1010LT via an old, beat-up, road-weary 16-channel mixing panel. This basic setup (different computer and distro, same sound card, cables, mics, etc.) was working fine at the old place in the basement. But now when I plug my mics (ie: Shure SM58) via XLR into the panel, I hear a LOT of radio interference. I never used to get any of this. My first thought is that the location (way up in the air) is what is causing it. I already tried the cheapest/quickest/easiest fix, new cables. That made no change. I will try plugging the unit into another outlet and see if that helps. I have the following questions for the more experienced readers on the list: 1) Could it be my beat-up old board? Does a newer, better board (ie: modern Mackie, etc.) have fewer problems with RF? (I know it would be quieter!) 2) I'm afraid that the RF might be coming through the power lines. Any tips on eliminating this? 3) Is the location of my equipment (3rd storey attic) an issue? Any way around this without shielding the entire roof? :-P Thanks for any help! Jay