[Bob Simon[_2_]]

When I connect audio out from my cable box to my pre-amp, I get hum. I was able to eliminate it for a couple of years by inserting an isolator (ISO-MAX VRD-1FF) just ahead of the Contour cable box.

Two days ago, the cable company disconnected my cable TV service because they determined interference was coming from my house. Yesterday, a Cox technician looked at my connections and stated that the source of the interference was my isolator. He directed me to remove it, performed a measurement, and said that everything was ok now, so he reconnected my cable TV service.. No surprise - the hum is back.

1) Is the hum caused by cable ground being at a different potential than house ground?

2) There is a rod in the ground just below my electric meter. A clamp on this rod is connected to a thick copper wire which goes to a cold water pipe and then it goes into the back of the main electrical panel. Is this my house ground?

3) If the cable ground were connected to this grounding rod, would this solve my problem with hum? Should this be done or not?

4) Is the cable company responsible for doing this?

5) Is it a violation of code for the cable not to be bonded to house ground?