Live TV signal interference

Good morning,

I just moved into a new house and the living room where our TV is has a four LED lights on a dimmer switch. When the lights are turned on to full power, some channels start having signal interference issues (i.e. pixelation, sound issues, screen freezes). The signal issues go away when you turn the lights off.

I noticed in the utility room that the coax cable going to the xfinity box is stapled together with a bunch of electric wires on one of the joists. 

Could that be the cause of the signal inference?

What other steps could I trouble shoot?

Should I replace the coax cable with a better shielded one?

Thank you.

-Mike