Very strange audio issue

[eopian]

Here is my setup:

Abit IS-7
p4 3.2EE
chaintech av710 (spdif passthrough)
happauge pvr-500 mce
fusion hdtv 5 lite
6600gt (agp) (2 monitors, vga to monitor, dvi<->hdmi to tv)

At school I lived in an apartment with a small hd antenna (but didn't have the chaintech av710 yet) and everything worked great. Since I've moved home (I graduated) my small antenna hasn't worked (3 months or so that I haven't tuned hd), I have upgraded the sound card, and everything worked great. Last week I purchased a heavy duty hdtv antenna with a pre-amp, and all of a sudden I have issues. After about an hour of watching hdtv on the computer with sage I get this static noise issue. It sounds like a digital noise on top of the audio I'm listeneing to and it is very annoying. The strange thing is that this is that this noise is on all types of sound (standard def, music audio, etc) until I reboot (then after an hour or so the noise kicks in again). When a dobly digital sound stream is played, you just hear random bits of sound very softly, no real audio). This started happening within an hour of plugging in the hdtv antenna starting to watch tv.

Has anybody seen anything like this before? What did you do to fix it?

Thanks!