Audio Systems: radio wont play, line amplifier, infinity sound

Question
I have a 2003 Dodge Stratus with the factory installed radio/CD player. The CD player works fine but the radio comes and go's.Most of the time I only get static. Do you think this is a radio problem or maybe an antena problem? I would hate to buy a new radio and have the same problem. Thanks for your help.

Answer
some of this vehicles with the infinity sound system have the amplifier in the back window there is also a line amplifier
there is only 1 wire look for power there and check the antenna conections also window tinting can be a problem if tere is metal in the film