Hoping someone can help me out on this

I have a 02 Audi 1.8T Quattro that works like a charm, with the exception of the radio dying after about 20 minutes, goes right to static. It's a Symphony II and the CD player and the tape player work just fine for hours and hours.

It does not appear to be a reception issue, as the radio initially gets a strong signal in my driveway, but still drops out at about the 20 minute mark without moving a foot.

Any ideas?