Something really nice about radios is they don't require an internet connection to work. You can use one as long as you have charge on your phone. I miss that.
Also, FM radio is very light on battery. You can probably listen it for a day and battery won't die. While, when you're streaming music, battery dies really quick.
If your phone has a jack, go and download a radio app if your phone didn't come with a stock one.
There was an app called NextRadio which activates FM radio on some supported devices, though I don't know what happened to that project. It hasn't been updated for a long time. Other than that, I'm not sure if there is any other alternative to that app beside the one that comes with a phone.
My Xperia has really annoying problem; whenever signal is low, it will constantly interrupt