Itzben said:
I didn't know it worked like that, its just on amazon I can get a portable dab radio which doesnt have any data so I was wondering why my phone apps use data
Yes, but a DAB radio and your iPhone work on entirely different principals, despite being able to play the same DAB radio channels.
Whenever you start using data on your phone, your putting extra strain on your carriers network as the data going to and from your phone is an individual data stream, so each listener would require their own stream of data, thus using lots of data
The DAB radio taps into a broadcast stream, this data stream is one way, but more importantly anyone can tap into it, and the amount data being sent out, is the same no matter how many are listening in.
so in short, the DAB app uses your phones data, because it cannot tap into the DAB radio streams, but instead puts additional strain on your carriers network.