Ask HN: Any API's to broadcast radio? (the old kind, not Internet radio)

I find the quality of radio when driving around town to be very severely lacking. I think the general trend of internet radio will continue, but lots of cars won't be equipped to get internet radio for a long time.

So I was wondering: 1. What the rough costs are to get unused air time 2. Would it be possible to create an API or some easy way for people to publish content

The idea would be to let niche radio appear (maybe HN Radio as an example). Costs (and advertisements) could be drastically reduced by either letter people broadcast from home with a skype headset (crowd sourcing it), or even automating the content with interesting audio books, talks, podcasts, etc.

I'm not sure what the cost would be to just get the air time or where to start thinking about coding up such an API. Has anyone thought about this?