For more than five decades, Joe Siedlik of Omaha brought what he called “happy music for happy people” to listeners — and dancers — not just in Nebraska but all across the country. His “Big Joe Polka Show” aired on radio for more than 25 years, becoming a Sunday fixture for many. At one time, he was on 30-some stations from California to New York. He hosted TV shows and polka festivals, promoting the music he loved and polka bands along with it. Siedlik, 80, died at Bergan Mercy Medical Center in Omaha, said Janie Romero of La Vista, his daughter and former TV co-host. He’d been diagnosed in mid-December with an aggressive form of cancer. “Polkas are just part of our life,” she said. “It was just what he believed in, ‘happy music for happy people.’ ”