Remedy for poor AM car radio reception?

I have a 2001 Ford Mondeo, and the AM (Medium Wave) radio reception can be very bad. Usually it is ok at the start of a journey, but then as time goes on, there is increasing amounts of a harsh noise (like 'static'), which eventually overwhelms the signal and makes it unlistenable. The FM reception is... show more I have a 2001 Ford Mondeo, and the AM (Medium Wave) radio reception can be very bad. Usually it is ok at the start of a journey, but then as time goes on, there is increasing amounts of a harsh noise (like 'static'), which eventually overwhelms the signal and makes it unlistenable. The FM reception is usually always ok.
I can't relate the interference to anything else in particular, such as weather or obstructions, and I'm not sure these should matter much.
Any ideas?

Thanks in advance.
3 answers 3