http://www.amusicdirect.com/products/detail.asp?sku=AMONDBOX
Google has many other hits for "Mondial Magic".
If you want to be sure this is the problem, a cheap way would be to go to radio shack, and buy 2 75-300 ohm baluns. The kind you used to use to hook up cable tv to an old tv with just antenna screws. Take the 2 baluns, and hook them together by the wires. Either clip off the spades and just twist and tape for this experiement, or you could just use screws and nuts.
Now plug your cable feed into one end, and run a new cable from the other end to your cable box. If this eliminates the hum, you have found the source of your problem. Then you might want to spend the money on the Mondial.
John
Google has many other hits for "Mondial Magic".
If you want to be sure this is the problem, a cheap way would be to go to radio shack, and buy 2 75-300 ohm baluns. The kind you used to use to hook up cable tv to an old tv with just antenna screws. Take the 2 baluns, and hook them together by the wires. Either clip off the spades and just twist and tape for this experiement, or you could just use screws and nuts.
Now plug your cable feed into one end, and run a new cable from the other end to your cable box. If this eliminates the hum, you have found the source of your problem. Then you might want to spend the money on the Mondial.
John