FreeviewHD tv won't work properly with foxsat HDR turned on.


I know this is a bit off topic but anybody know why the sound plays up when i connect the ariel and then turn on my foxsat. I thought it would be useful to have while I'm recording two programmes on the foxsat, and then i can watch anything else on freeview now it's just gone HD in my area. The trouble is as soon as the foxsat's turned on you get a loud hiss coming from the speakers (creative T20 plugged in to the ear jack) This happens on any source -TV- DVD-PC- etc. As soon as you pull the ariel out it's fine. It's also fine if you pull the hd cable out coming from the foxsat. then the freeview works great. If you turn the foxsat off it's ok as well. Checked all cables and their fine but put the ariel back in and the noise starts. It's a shame as this would be very useful. It seems to be ok when you pull the speaker plug out and use the tv speakers. So it would seem to be a problem with the external speakers. Anyone know if you can solve this?
My guess is that the source of the problem is the power supply of the Creative speakers inducing interference in the other cabling.
If I have my laptop connected to HDMI2 I have to switch off, or unplug the HDMI from the Humax box to get sound from the laptop on the TV, even though I have HDMI2 selected on the TV.