Here's my situation: I am getting a hum on my home theater speakers, when I unplug the cable input to my tivo box, the hum goes away. I assume this to be a ground loop issue. The cables for CATV appear to be attached to grounding blocks which are connected to a copper wire which runs back into my house and is clamped to what looks to be metal conduit coming out of the panel. Another piece of what looks like metal conduit comes out of the side of the panel, goes near the floor and is clamped to what appears to be a grounding rod coming out of the basement floor. Both the clamps and the grounding rod are very rusty.

1. Is it possible for this grounding rod to be serving any grounding purpose at all if it and the clamps are so rusty? And as a consequence, could this be causing the hum in my speakers?

2. If a new rod needs to be installed, it seems as though it should be done outside the house... yes?

3. Does it matter where the grounding wire from a new rod attaches to the panel?

4. Anything else I should consider?

Thanks