DAB allows broadcasters to broadcast some radio services only at certain times of the day. The BBC uses this facility to broadcast Radio 5 Live Sports Extra and Radio 4 LW.
Such services are sometimes classified as secondary services.
Where can I find them?
When Radio 5 Live Sports Extra is on air, you should find it right next to 5 Live on the list of stations on your digital radio. The same is true for Radio 4 LW on DAB. It can be found next to Radio 4 on the list of stations.
When do they broadcast?
Radio 5 Live Sports Extra has a dynamic schedule. To see what is available when, the BBC keeps a schedule on the sport website. Radio 4 LW normally broadcasts Yesterday in Parliament, The Daily Service and the Shipping Forecast each day.
How to find these services
It is best to re-tune your radio when they are broadcasting, so it will store the station in its memory.