I never had problems in terms of signal strength with my N900's FM transmitter in cars.

The only thing that has become increasingly difficult over the past 5 years is, that radio stations have been packed increasingly dense on the available spectrum. You want to be at least 1 MHz away from the next official channel to get a clear signal.


Neither can I. But at 2m distance to the receiver's antenna I can at least compete with any official station, and Helene Fischer plus Metallica still equals T(h)rash Metal.