Early cell phones often had a built in FM tuner and app to receive local terrestrial radio stations.   The FM transmitter chip is still installed in many modern smartphones but is usually disabled by the manufacturer to encourage the paid use of data plans.  This feature was replaced by modern data streaming apps such as IHeartRadio which bypass the built in FM tuner.

This presented a problem during recent hurricanes and other natural disasters when cell phone towers were down and widespread power outages occurred.  Only those individuals who already owned conventional radios with battery powered backup were able to receive emergency public radio broadcasts.

The National Association of Broadcasters (NAB) developed a free smartphone app – NextRadio – that attempts to use the FM tuner, and then uses Wi-Fi if the FM tuner is not available.   (Some phone manufacturers still include a built in FM radio app.)  A list of compatible phones and phone plans is available at nextradioapp.com/supported-devices.   Plugging in a set of headphones acts as a radio antenna to increase reception.

Apple currently has no plans to turn on this feature in iPhones, according to ZDNet.com.