Originally Posted by SamS
There are antennas inside the car, and the signal has to pass through the glass to get to them. There are several threads on this topic, with users who have struggled with CA after they got tint.
Simply, they got the wrong tint. Use an extruded (such as Madico Charcool) or a ceramic film (such as 3M crystalline) and you'll have no signal degradation from either CA or your stereo.
Plus film will protect your interior from harmful UV rays that will age the interior.