W251 radio woes

[wolfie1978]

I'm having trouble with the radio in my R class as in it's not picking up radio stations very well. i've swapped out the antenna amplifier in the boot the other week and it is a bit better, the clock has set to the correct time and the 1 local station it could get in a small area of town i can now get in more areas of town but i still can't pick up any national stations. What would my next step be?