Symphony II - No AM Radio - Help!!

[johnnyhatesjazz]

I've recently bought a 2003 S6 Avant, with standard Symphony II system....tape player, 6 CD slot load jobbie. FM radio & CD all sound fine (though not a patch on my old Lexus LS400 system!), but only light static across the whole range of AM frequencies. I've tried swapping the aerial with a known working one, but no difference at all. Any ideas much appreciated.
Also, how can I tell if it's a Bose system or not, and how big a job would it be to upgrade to a Navigation Plus system? Whats the difference between the original and the rnse units?

Any comments appreciated,

Johnny.

[S8QUATTRO]

I am not the best person to advise on the static issue but you'll know if you've got BOSE as all the speakers have a little sign of the Audi rings with the BOSE logo next to it. In addition, when you turn on your stereo, the word BOSE is briefly shown on the screen as the stereo starts itself up.

Perhaps on the aerial front, you could try a stubby version which are supposedly more powerful.