My speech craft role model is probably Greg Beharrell. He's the host of The Greg Beharrell Show which airs on a local radio station that I listen to when I'm driving. I love listening to him because I think he's really funny. He has a very dry sense of humor, and he delivers it perfectly every time. I would assume that most of the speaking parts of his show are either manuscript speeches or extemporaneous speeches. However, he takes a lot of calls from his listeners, and those are impromptu speeches. The speaking that he does is a civic model of speech since he's speaking to a large audience that isn't responding, but it can also be a conversational model when he's speaking with listeners on the phone. I consider Greg Beharrell to be a speech model because he's very good at a lot of different types of speeches, and because his humor makes him very engaging to listen too!
I agree that it is nice to find a radio speaker who can engage the listeners without necessarily having to converse with them. Too often I have found radio speakers to be boring, not funny, and overall not entertaining enough to keep listening to their radio show, and, because of this, I stopped listening to the radio. However, I am glad that you have found such a good station to listen to and it is amazing how Greg is able to engage you and the rest of his audience with so many diverse speech techniques.
I don't listen to the radio very much, but it's always interesting to hear the calls people make and the responses they get. This host sounds like a very good speaker compared to other radio hosts. Humor is definitely a must when I'm listening to others talk.