BBC National DAB
BBC National DAB is a digital audio broadcasting multiplex in the UK, for a number of radio stations which have UK wide coverage. The multiplex is owned and operated by the BBC and is transmitted from a number of transmitter sites across the country; it only carries BBC radio stations. As of the end of 2017, more than 97% of the UK's population are within reach of the multiplex following the completion of the switching on of a fourth set of new transmitters over the previous two years which had seen the reach increase from 93%. Any further expansion of DAB radio is awaiting a decision by Government on any possible digital radio switchover. Stations carried
The following channels are receivable on any digital-equipped DAB radio in the BBC National DAB coverage area:

Full time services

Part time services
The BBC National DAB multiplex makes use of dynamic ensemble reconfiguration to allow a number of part-time services to broadcast. While these additional services are on air the bit rates of (one or more of) BBC Radio 3, BBC Radio 4, BBC Radio 5 Live, and data services are reduced. "Pop-up" services
The BBC has experimented with short-term "Pop-up" digital radio stations, each broadcasting for approximately four days at a time, covering music festivals and other special events. The first to broadcast was BBC Radio 5 Live Olympics Extra in 2012, then BBC Radio 2 Eurovision launched for the first time in 2014, and was joined by BBC Radio 2 Country, BBC Music Jazz in 2015 and BBC Radio 2 50s in April 2016. When these temporary stations are on air, there is normally a reduction in bit rate of their parent station. Threat of station closures
In 2010, the BBC published plans to close BBC Radio 6 Music and BBC Asian Network. These plans were later rejected, saving both stations from closure. Radio 6 Music was retained after listening figures increased and a campaign was set up on Facebook, which gained 180,000 supporters. See also
Timeline of Digital Audio Broadcasting in the UK

References

National DAB
Digital audio broadcasting multiplexes