This may not be the most optimum time for Tribune Co. to be shopping itself. In a second-quarter filing on Thursday, the media giant said that operating profit fell 28 percent to $90 million. And the downturn was not simply a reflection of its newspaper woes, although revenue from its newspaper business -- its principal newspapers are the Chicago Tribune and the Los Angeles Times -- slid 4 percent from the comparable quarter a year ago. No, most of the decline came from a 20-percent plunge in revenue from its broadcasting revenue, with WGN-TV in Chicago and WPIX-TV in New York being particularly hard hit. Peter Liguori, Tribune Company president and CEO, tried to put a positive face on the figures. While our second quarter financial results reflect many of the same challenges faced by the other companies in our sector, we have made substantial progress strategically repositioning Tribune for long-term growth, he said in a statement.