Public radio/television is funded by, in something vaguely resembling order of importance, listener-sponsors, corporate sponsorship and government funding.
The listener-sponsor funding comes from individual donations that are solicited in thrice yearly pledge drives during which they spend about twenty minutes out of every hour, usually in two ten minute segments on the hour and half hour. These drives generally last about a week to ten days.
The corporate sponsorship results in brief announcements during station breaks for the local sponsorships and during the intro or outro to a show for nation-wide sponsorships. These announcements sometimes verge on commercials; the information given can be more than a mere announcement of the name of the sponsor.
Government funding, as I understand it, is dependent on the amount raised from listener-sponsors. This funding has been decreasing in the past few years because of trickle-down tax cuts.
