Happens because a scanner with a ducky inside a car does not get enough reception, the aluminum body of the car shields much of the reception, signals can only get through the windows of the car to your handheld scanner. But it also has to do with the area you live in. I live in a rural area with 2 sq mile towns, so the repeaters around here are low power and the terrain varies widely. It is nearly impossible to monitor with a scanner inside the car while driving in my area. The reception will keep breaking up... I installed an outside mobile antenna on my trunk and now it's great because the antenna is outside without any obstruction (aluminum roof) and so the reception is much better, the way it's supposed to be.