The 24-hour news and sport network will run a programme called Now The Good News every Friday evening, from 9pm to10pm.
It will go out as long as breaking bad news, such as a mortar attack on Heathrow, does not upstage it, sending the station into a rolling news and comment format.
'Nobody else does it,' said the network controller, Jenny Abramsky, who made her reputation as editor of Today.
She plans to leave the current Radio 5's sports coverage undisturbed, while changing everything else around it. About 150 employees are being recruited to staff the news programmes: a good proportion come from local radio, with BBC stations and London's LBC, which loses its franchise in October, being plundered for talent.
Jane Garvey, formerly of BBC Radio Hereford, will present a heavyweight daily news round-up between 5am and 6am, called Morning Report, then read the news in The Breakfast Programme, presented by the former ITN veteran, Peter Allen.
'There is a steep learning curve. None of us has created a new network before,' Ms Abramsky said. 'Hell, I am terrified. It is a huge amount of airtime.'
Staffing is low for the amount of airtime to be filled. The Magazine, which runs every weekday morning from 8.35am to noon, has only 11 people working on it, less than a 40-minute news programme on Radio 4.
Because of the danger, obvious from pilots, of everyone chasing the same interviewees and stories, Ms Abramsky has decided to set up a separate planning desk of 12 producers, but this will not be in place for the launch.
The station will pay careful attention to the different regions to counteract the BBC's traditional bias towards the South-east, aiming for a young, broad market. There will be programmes for black people and Asians, along with a weekly gay and lesbian programme, Out This Week. Stop Press, dropped by Radio 4 for its Medium Wave returns on Friday evenings and there will be a news programme dedicated to computers.
'I've asked to widen the agenda, tackle a number of minority issues,' Ms Abramsky said. 'Nobody said we were going to do tabloid radio.' Radio 5 Live would be positioned between the Daily Mail and the Guardian.