The medium, long and short wave ranges provide greater reception range because radio signals propagate not only as surface waves that bend around the Earth, but also as spatial waves reflected by the ionosphere.
The VHF (FM) range provides significantly better sound reproduction quality than any other waves. However, the range of radio stations operating in this range is limited due to the rectilinear propagation of ultra-short waves. Certain limitations in reception are partially compensated by "clever" systems.
RDS system (Radio Data System) provides automatic selection of the frequency with the highest reception quality if the radio station broadcasts on several frequencies.
The antenna diversity method means that several antennas for receiving ultra-short waves are built into the rear window. Thus, the car has three independent antennas. The built-in processor automatically selects the antenna that provides the best ultra-short wave reception. Switching from antenna to antenna is done in a matter of milliseconds and is completely unnoticeable for a person.
[The original source of the article is on the website: «bmwman.ru»]