I think they should emulate NPR. That is to say, they should be commercial free, supported by listeners and other donors.
At one time, I listened to a Christian radio station while driving to work. And there were lots of advertisements. Some of the ads seemed to be from sleazy outfits. When people listen to Christian radio, they don't expect to be scammed. The safest way is to keep the station commercial free.
Note: I stopped listening when they switch to become a rock music station. This suggests that it was really always about money.
Note2: When I suggest emulating NPR, I am talking only about the support model. Obviously the programming and content would be different.
Fundamentalism - the anti-American, anti-Christian branch of American Christianity