DRM AFS

DRM can transmit programme information regarding alternative frequencies and alternative broadcasts for the broadcast currently being received, including broadcasts on AM/FM and DAB. If reception on the current tuned frequency is poor then the DRM radio can briefly switch to an alternative frequency and asses if this new frequency provides better reception.

This is done ‘seamlessly’ without loss of audio but unlike VHF-RDS (Radio Data System) does not require two independent tuners. Information coded into a SDC block (SDC data entity type 3) and FAC informs the radio if and when this switch can take place. Other SDC blocks give information on programme schedules, etc.

Two examples of AFS provided by the BBC and Deutsche Welle, decoded using Dream software (AFS decoder written by Andrea Russo).