The medium, long and short wave bands provide a greater range of reception, since radio signals propagate not only as surface waves that envelop the Earth, but also as sky waves reflected by the ionosphere.
In the VHF band (FM) provides significantly better sound quality than any other waveform. However, the range of radio stations operating in this range is limited due to the rectilinear propagation of ultrashort waves. Certain restrictions in reception are partially compensated "cunning" systems.
RDS system (Radio Data System) provides automatic frequency selection with the highest reception quality when the radio is broadcasting on multiple frequencies.
The antenna diversity method involves multiple antennas being built into the rear window to receive the ultra-short waves. Thus, the car has three antennas independent of each other. The built-in processor automatically selects the antenna that provides the best VHF reception. Switching from antenna to antenna is done in a matter of milliseconds and is completely imperceptible to humans.