Multipoint Aerials

Digital audio broadcasting (DAB) is a digital radio standard for broadcasting digital audio radio  services, used in countries across Europe, the Middle East and Asia Pacific.

The DAB standard was initiated as a European research project in the 1980s. The Norwegian Broadcasting Corperation (NRK) launched the first DAB channel in the world on 1 June 1995. and the BBC and Swedish Radio launched their first DAB digital radio broadcasts in September 1995. DAB recievers have been available in many countries since the end of the 1990s.

DAB is more efficient in its use of spectrum than analogue FM radio, and thus may offer more radio services for the same given bandwidth. DAB is more robust with regard to noise and multipath fading for mobile listening. Although DAB reception quality degrades rapidly when the signal strength falls below a critical threshold, whereas FM reception quality degrades slowly with the decreasing signal, providing effective coverage over a larger area.

The original version of DAB used the MP2 audio codec. An upgraded version of the system was released in February 2007, called DAB+, which uses the HE-AAC v2 audio codec. DAB is not forward compatible with DAB+, which means that DAB-only receivers are not able to receive DAB+ broadcasts. However, broadcasters can mix DAB and DAB+ programs inside the same transmission and so make a progressive transition to DAB+. DAB+ is approximately twice as efficient as DAB, and more robust.

In spectrum management, the bands that are allocated for public DAB services, are abbreviated with T-DAB, where the "T" stands for terrestrial.

As of 2017, 38 countries are running DAB services. The majority of these services are using DAB+, with only Ireland, UK, New Zealand, Romania and Brunei still using a significant number of DAB services.  In many countries, it is expected that existing FM services will switch over to DAB+. Norway is the first country to implement a national FM radio analoge switchoff, in 2017.