Audio Systems: BMW 98 528i AM radio static, radio noise, noise problems

Question
My am band on the low end is so staticy I can hardly listen to it. I have had the car for a year and it has been that way since I've had it. I've been told that BMW radios weren't any good, especially the AM band. I have been told the tint over the back window where the antenna is may have metal in it which affect reception. I've been told so many things I don't know what to believe. Any suggestions.

Answer
i saw 2 or 4 cars with radio noise problems getting some radio stations and bad quality  and it was the metalic window tinting  
also near the back window there is a factory amplifier for the antenna only
one last thing if they clean the window to remove the tint and they use a knife or blade to clean the window or metal brush the line will get damage and the only solution is to replace the back window