My Sony BX70DBI has rubbish radio reception. At times (rarely) it is fine. Mostly it sounds like it's being broadcast from under the sea! The signal drops out randomly and then returns again for no apparent reason. Is this a device fault or something to do with the DAB signal? I'd love to know what is causing it and how best to solve it. I have spent a lot of money for a better radio signal and just got garbage!!!