Here's the article that lists the do's and dont's.

From that list, the things that I could've done wrong, that I can think of, are-

-Using a shielded cable.

-Possibly stretched the cable.

-Running them parallel to the power lines is affecting them (I was told by a customer support representative of a well known and well respected cable manufacturer that this wouldn't be an issue).

Any suggestions?

Just thinking of all the possibilities before I have to rally some troops (not easy) to take the TV off the wall. I want to know everything that should be tested, while it is.

The only reasonable argument for owning a gun is to protect yourself from the police.