silverstreak

When driving home Saturday night in my otherwise wonderful 2000 E55 with COMAND, I was appalled to find that I couldn't get more than a faint intermittent signal from the AM radio station that was broadcasting the Raiders/Patriots game. This was in an area where my other vehicles have always been able to get pretty decent reception. This morning I tried all three of our cars' radios (one domestic, one Japanese, and the Benz) in the driveway, and found the MBz AM radio practically worthless (one weak station, the other cars got seven to ten stations). The FM section works just fine.
Does my E55's AM radio need repair, or are they all putrid?