According to their website, the public pays for 1-2% of their budget, which comes as grants from other publically funded organizations such as NEA, etc. Like you, I thought they were wholly funded by taxpayers so I a little investigations.
Follow the strings a few more rungs back. They are not (and I never thought they were) entirely funded by the gov't, but it is a whole lot more than 1-2%. Look at how many grants they get and programming costs paid from non gov't entities that are themselves funded by the gov't, like the CPB, corporation for public broadcasting. It is a web deliberately designed to obfuscate how much of their money is coming from taxpayers. While I have not seen anything about this program or station in particular, I have seen the sources of one of the NYC's NPR's dissected. About 40% of their money came from taxpayers, although usually through a very complex web of grants, fee sharing programs, cost sharing programs, etc etc etc. One of the things they do is pass money back and forth between levels to make it seem like there is more 'non-gov't' money in the system than there is. From a money in and money out perspective, I bet it is comparable to the 40%.