i have found nthat it depends on the car. some cars wioll work great on the dash and some wont work at all on the dash. try the dash first and drive around with it for a few days, and if you are getting bad reception, then mount it on the roof.
i have found nthat it depends on the car. some cars wioll work great on the dash and some wont work at all on the dash. try the dash first and drive around with it for a few days, and if you are getting bad reception, then mount it on the roof.