bobpaul wrote

A few things.

  • Not all Bluetooth chipsets have FM receivers.

  • If it exists, the FM receiver only works if the antenna pin is connected (generally to the headphone ground, but a dedicated antenna can also be used).

  • Phones that both have a receiver AND have it connected to an antenna generally list FM radio in the specs and come with FM radio software.

With regards to the iPhone specifically, the latest iPhones don't even have a headphone jack and they certainly don't have a dedicated FM antenna. Apple claims they use a chipset that lacks FM.