All about DAB multiplexes

 

DAB Digital radio services (or stations) are grouped together in multiplexes, sometimes called ensembles. A multiplex consists of a stream of digital information containing a mixture of the audio from a number of services and other data. Packing services together in this way makes very efficient use of transmission resources: the UK has several multiplexes which between them contain many radio services, and the number continues to expand. Some are available nationally, and some cover localised areas. This type of packaging isn't possible with FM and AM which is why we had far fewer stations before the advent of digital radio. 

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National, Regional and Local Multiplexes

Not all multiplexes serving your area necessarily come from the same transmitters.  National multiplexes are designed to serve wide areas using a overlapping coverage system called a Single Frequency Network. This passes your reception from one transmitter service area to the next as you move, ensuring seamless listening if you are driving.

Local and regional multiplexes are licensed to serve specific areas only, and are not meant to overlap. Transmitter sites are chosen with this in mind and may not always be the same as those for national services. In cases where the sites are the same, transmitter powers and coverage areas may still differ between national and local services.

Which multiplex is my station on?

If your reception of some DAB stations is better than others, knowing which station is on which multiplex may help you work out why. Information and full lists of the services can be found at:

The display on your DAB radio may provide you with the number of the multiplex on which you are listening, if you follow the instructions.

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