Good work. There are numerous recordings and videos of plasma TV noise on the web that you can compare to. If it is a plasma type, the only solution is replacement with an LCD TV. If it’s just the power supply in it then it’s possible it could be tamed with chokes. There’s another possibility, maybe a bad cable box or other accessory like a DVR. Don’t assume too much. Fortunately TVs are pretty cheap now, so if it did have to be replaced the several hams affected could split the cost if need be. Most people wouldn’t willingly shell out hundreds of dollars just because the ham next door has a problem. But you might get lucky, maybe he or she wants to get a new TV anyway and would be willing to replace it.