I have 2 horizontal flashing sparkling lines about 1 inch apart on all of my 3 TVs. They start at the bottom of the screen and move up to the top. Primarily on channels 2, 4, 5. (ch 4 is my satellite receiver which is modulated then combined with off air antenna.) This only happens when the furnace turns on. My understanding is that there are 2 fan motors in the furnace. 1 fan motor is for venting fumes out of the home and only runs while the burner is on. The 2nd motor is for pushing heat through the ductwork to heat the home. Then there is this electrical igniter that lights the burner that makes a buzzing sound until the burner is lit. There is also an electrical solenoid valve that opens to release natural gas to the burner and that stays on until the thermostat isn’t calling heat any more. The lines do not appear when the 2nd motor is running by itself. (i.e. when thermostat is no longer calling for heat the 2nd motor fan runs until burner cools off.) Is my problem a ground loop or improper grounding or bad furnace components or something else and what would be the solution?