Hi - I have a 850 2.5 GLE 1995. The FM reception of the standard SC-801 is fantastic - Its the best radio reception i've ever heard in a car. But now i've installed a Becker Traffic Pro Sat Nav head Unit and the Fm reception is only fair. I can get a handful of the strong national channels (slightly fuzzy) but I can't even get the local FM station and a lot of the channels I used to listen to are missing or hardly audiable when I tune to them. When I put my factory unit back in, everything is perfect again. Has anyone had this problem with aftermarket head units. I can't believe the tuner on this £1000 unit is crap. What am I missing?
How come the aerial is so good with the factory set and not with a different one?

So far I've ground the head unit to the car body earth with a thick wire, tried three different old type to ISO aerial adaptor leads, adjusting the aerial trimmer screw on the Becker makes no difference, and the aerial amplfier supply wire does give 12v when I switch the radio on. I'm just about to set up a temporary regular whip aerial to see if that works. Sigh....