WEST PALM BEACH, Fla. — Paxson Communications Corp. said it will sell its radio stations, billboards and two minor-league sports teams to Clear Channel Communications Corp. for $693 million in a surprise move to focus on television. The 46 radio stations, 526 billboards and two teams generated about 50% of Paxson's 1996 revenue of $165 million. To build its TV business, the West Palm Beach-based company recently agreed to buy the Travel Channel and the WBIS+ station in New York. The moves will help Paxson focus on expanding 55 TV stations into the nation's seventh broadcast network, behind the UPN and WB networks. Clear Channel, meanwhile, will add to the 123 radio stations it owns or operates and to its 50,000 outdoor displays. C Paxson, the nation's largest TV station owner, reaches about 58% of U.S. homes. The company has said it plans to reach 70% of the nation by early to mid-1998 and reports that it is negotiating with major broadcast networks, movie studios and cable operators to develop a new national TV network.