CAPITAL RADIO GROUP has unveiled plans to invest £5.5m in a new music broadcasting website. Ad revenues, said chief executive David Mansfield, had more than met expectations and Capital now seeks to make a number of strategic investments. The aim is to gain a national presence, achievable, believes Capital, through the internet. The Capital name will lend itself to an online following, Mansfield says. However, he was zip-lipped about the details, conceding only that the broadcasting website would exploit customer loy-alty and the group's close contacts in the music business.