Wonder if anyone could help me! Just installed a cheap and cheerful cd/mp3 player in my 6 year old bmw, small antenna on back window. I only ever use the unit in my car to listen to mp3 discs and radio 5 on MW yea sad I know. All radio channels on the new system but this are loud and clear?? Besides putting in a larger antenna, which I don't want to do, is there anything else I can do?