I got a passive coax ground isolator device - it worked great.
|Originally Posted by Ratman|
I'd call your cable provider and have them fix the problem.
|Originally Posted by AntAltMike|
Most input cables are grounded adequately. A ground loop is formed when you have some other path to ground in the system that is not at the exact same potential and a lateral connection between the two forms a "loop" antenna, thus the term, ground loop.
You should be able to eyeball the cable ground to see if there is one and if it goes to something suitable. If it goes to the big, ten gauge or larger wire that the phone company uses, then it is not the cause of your problem, even if such a connection might not technically meet the current code specification.
Once you determine that the cable input is grounded, there is no more practical way to make the hum go away than with a ground loop isolator. I've bought over a dozen of the Holland product linked above, and I paid a lot more than that price for them. They work just fine. Such devices do NOT in an way defeat the safety of the exisiting grounds. They are not ground lifts. They just disrupt the superfluous lateral connection that completes the loop.