Poor radio reception

[audicab26]

Hi

My 2002 Passat Estate has an aftermarket Kenwood Radio/CD. When I got the car it had a cheap Sony which I swapped out for the Kenwood.

The problem is the radio reception is dire. I bought an powered amplifier/adaptor for the aerial that plugs into the aerial socket on the back of the set and that if anything has made it worse! The aerial itself is ok and I tried a new one - no difference.

Is there anything else I should check/change as it is driving me mad! Note, the aerial amp/adaptor was a fairly cheap item from ebay (about 3 quid) - is there a particular type I should get? I understand that the OE unit would have had one fitted?

Thanks in advance.