According to the blog of the Public Radio Program Directors Association, Classical Public Radio Network is signing off sometime this summer. The around-the-clock classical feed is one of several available to public radio stations looking to fill airtime without having to rely on local staff. Many stations use CPRN or one of the system’s other services, such as Classical 24 or the Beethoven Satellite Network, to fill at least part of their music schedules. Launched in 2003, CPRN, one of the newer services, is a collaborative effort between KUSC in Los Angeles and Colorado Public Radio. I hope to have more details after I make a few phone calls…