I’d noticed what you pointed out about stations that carry conservative talk radio as well. I can’t think of one example where there is a non-conservative talk show one a station that carries Limbaugh.

I work on a local science fiction convention that I’ve been attending since 1976. Sixteen years ago the ringing phone woke us up just a couple of days before the convention with the news that the woman who was running our art show (Who at that time was in her 40’s.) had suffered a massive stroke. It was questionable whether or not she’d survive. The time for the convention came and we had found someone to assume her duties but the entire weekend was consumed by asking your fellow committee members if anyone had heard any news. Was she still alive? What were her prospects? What a weekend that was, so full of anxiety and yet still having to keep doing what we’d promised our attendees we’d do and keep the convention running. She survived but the stroke left her permanently debilitated.

http://ajliebling.blogspot.com/2007/06/poor-john-edwards.html