Chrysalis Radio's Galaxy brand has extended its reach by broadcasting the service on Switch Digital's DAB multiplexes from January 2003.
The deal will extend Galaxy's reach across both London and Central Scotland, increasing its potential combined analogue and DAB audience to around 28 m listeners.
The latest expansion follows an agreement last month with Sky Digital to carry Chrysalis Radio's flagship Yorkshire station, Galaxy 105.
Chrysalis' digital rock format The Arrow has also been extended across the Central Scotland multiplex, increasing its potential reach to over 28.5 m listeners.
Chrysalis chief executive Phil Riley said: "These latest agreements further demonstrate Chrysalis Radio's commitment both to Galaxy and DAB digital Radio.
"We're delighted Londoners, and people living in Scotland's Central belt will now be able to enjoy listening to the UK's largest youth brand, as sales of digital sets take off in 2003."