Hello
Yes, cable tv is probably the culprit.
I have been told it can be caused by having more than one 3 prong (grounded) device plugged in too. Some people use a 3 to 2 prong converter to fix this but this is illegal in Canada and I'm guessing there is a good reason......like fire hazard or something.
I ordered a "ground loop eliminator" from parts express a couple of years ago.
It was expensive but it did what it claimed it would do.
Maybe one of the electronics guys on this site know how to make a "DIY" version for cheap.
If not, I would go for the parts express version.
The only thing that works better is unscrewing the cable connection.
