Three more Welsh language TV channels and three more radio stations could be created if broadcasting was devolved, campaigners have claimed.
Cymdeithas yr Iaith Gymraeg said an extra £60m could be spent on public service broadcasting through measures such as a levy on big media companies.
More than 50 Cymdeithas members are refusing to pay the BBC licence fee.
Welsh Government said accountability of broadcasters "should be shared by all institutions of the United Kingdom".
In February, an assembly committee called on the BBC to spend another £30m on English-language output for Wales.
Under plans published at the National Eisteddfod on Thursday, Cymdeithas said Wales could get about £190m a year from a proportionate share of the BBC licence fee.
The group added that a levy on companies such as Google, Sky and Facebook could raise up to £30m a year, with other money coming as a result of taking power from other bodies based in London.
Cymdeithas pointed to a YouGov poll which suggested nearly two-thirds of people in Wales were in favour of power over broadcasting going to the Senedd.
Author Angharad Tomos and Cymdeithas chair Heledd Gwyndaf are among members who are refusing to pay for their TV licence as part of their campaign.
TV Licensing previously said the campaigners risked prosecution and a £1,000 fine.
Carl Morris, chairman of the society's digital group, said: "Decisions about broadcasting in Wales should be made in Wales. And it's clear from opinion polls that the vast majority of the Welsh public support that.
"The state of broadcasting in Wales is extremely fragile and there's a severe lack of Welsh and local broadcasting on commercial radio and local TV.
"It's also clear that Wales has a severe democratic deficit, because UK broadcasters confuse people by reporting on all the decisions that only affect England."
Several online platforms and a new bilingual broadcaster could also be created, Cymdeithas added.
The call comes as the UK government launches a review of the future of the existing Welsh-language broadcaster S4C, which it part-funds.
A Welsh Government spokesman said: "We don't recognise the figures quoted by Cymdeithas yr Iaith.
"Our priority is ensuring Wales is appropriately represented. We believe that accountability of broadcasters should be shared by all institutions of the United Kingdom."
A spokesman from the Department for Digital, Culture, Media and Sport (DCMS) said: "The UK Government is committed to a broadcasting sector that benefits the whole of the UK, and the Silk commission concluded that there was no case to devolve regulation of broadcasting.
"Public Service Broadcasters are already required by Ofcom to produce regional content as part of their licence conditions."