hum coming from my subwoofer

Try a cheater plug. Did it for me.

You have a ground loop caused by your satellite reciever.
As Warrenh suggests you can ues a three to two cheater plug on your sub which will lift the ground or buy a ground loop eliminator. A ground loop exists when two or more grounds have a slight difference of resistance between them. This produces a voltage drop which will produce hums in your sub and possibly other gear. Hope this helps and Happy Holidays.

A friend of mine had a similar problem recently. He traced it to a loose ground connection at the cable tv input on the outside of the house.