An American television pioneer will be in Central Iowa this weekend talkingabout the downfall of the medium. Comedian, author, actor and musician SteveAllen is speaking in Des Moines about the vulgarity, filth, sex and violencethat dominates the airwaves.Allen is honorary chairman of the Parents Television Council. He is thecreator and was the original host of “The Tonight Show,” and says it wasn’tthat long ago that radio and T-V talk shows were fun, friendly andenlightening.The 78-year-old Allen is speaking Saturday before the Professional Educatorsof Iowa, meeting at the Drake University. He’ll also be signing his latest(and 50th) book at the West Des Moines Barnes & Noble. Allen says humansnever take long to “louse up” great inventions.Allen has some Iowa ties — his father used to run a saloon in Des Moinesback in the 1920s. Allen was born in New York but attended Drake Universityfor one year on a journalism scholarship.