The radio and television industry group has been in the top 20 of IBD's 197 industry groups for months, although just one of its stocks is a standout. Sinclair Broadcast Group (SBGI) -- one of the largest TV-station operators in the nation -- is the industry's leader. Its shares appear to be forming a base. The company's earnings increased 89%, 61% and 50% in the past three quarters. Sales jumped 22%, 34% and 44% as the company emerged from a weak