Poor radio reception
 

My kenwood ddx4017bt was professionally installed in a 2004 Mercedes clk cabriolet a few weeks ago but since then I've noticed very poor reception when travelling in outlying areas. My oem model picked these stations up well. I told the installer but said there was nothing he could do. Curious to hear the thoughts of othets on this matter. Seems like I am doomed to putting up with poor radio reception when making long trips.
Thoughts?