I am desperate for help with the following problem :- Recently installed Alpine 9845RR in my 04 Audi A4 Avant. The unit works very well apart from one annoying thing, the radio performance on FM channels. Basically, listening to the same stations as I did on the standard Audi radio there are lots of pops and hisses when I'm driving, as though all channels are weak signals. I have used the Autoleads wiring adapter for RCA input as well as the Autoleads PC5-91 antenna adapter for isolating the 12V from the radio aerial input while still powering up the Audi antenna booster. If I remove the 12V power to the antenna adapter the radio signal goes, so I would assume this means that the head amp is working ? Can anyone else suggest what this problem may be ?? or is the Alpine unit just poorer qualityn than the standard Audi head unit ?