Ground Hum & Ground Loop Isolators

[D]

You can also use two 75 ohm transformers, the type with a threaded female F-connector on one end, and a Y with spade connectors on the other. Cut off the spades, and splice the wires of the Y's together so the transformers are connected together. Put them inline with your cable feed. Should take care of the ground issue, for no more than a few bucks at radioshack.