Why some cars have antennas and some doesn’t, and what the “fin” looking like is doing?

Question

I see some cars have antennas (and some even have two) and some doesn’t.
Why is that? And why some have one or two what’s the matter with the count? And wha the matter with their length and the direction they are pointing?

And what’s the fin (𓂄) doing?

In: Engineering

Answer 1

Newer cars integrate the radio antenna into the back window. The top few lines of the defroster are actually the antenna.

The shark fin is a cell phone antenna. Any in-car apps or GPS that use data use the fin.