This namespace provides access to the FM radio features of Windows Phone OS 7.1.
FM radio is supported only in apps that target Windows Phone OS 7.1. If you use the FMRadio class in apps that target Windows Phone OS 8.0 or later, a RadioDisabledException indicates that the FM radio feature is not available. On Windows Phone 8 devices with a build of 8.0.10322 or greater, the run-time exception may not occur if you use the FMRadio API. However, the FMRadio API is not supported for apps that target Windows Phone OS 8.0.
If you use this API in your app, you must specify the following capabilities in the app manifest. Otherwise, your app might not work correctly or it might exit unexpectedly.
Windows Phone OS 7.1
For more info, see App capabilities and hardware requirements for Windows Phone 8.