WNAX (570 AM) is a radio station in Yankton, South Dakota, currently owned by Saga Communications, Inc., which broadcasts a news/talk format. WNAX broadcasts at 5,000 watts around the clock from a tower in eastern Yankton. Due to its location near the bottom of the AM dial, transmitter power, and South Dakota's flat land (with near-perfect ground conductivity) the station's 5,000-watt signal provides at least secondary coverage during the day to most of the eastern half of South Dakota, much of western Iowa, and most of the densely populated portion of Nebraska. In addition to its home markets of Sioux City and Sioux Falls, WNAX provides a strong grade B signal to Omaha and Lincoln. Under the right conditions, its daytime signal penetrates as far south as Kansas City, as far north as Fargo and well east of Des Moines with a good radio. Among U.S. stations its daytime land coverage is exceeded only by KFYR in Bismarck, North Dakota. A single tower is used during the day. Three towers are used at night to protect clear-channel stations on adjacent frequencies, concentrating the signal along the Sioux Falls-Sioux City corridor. History WNAX was first licensed on November 7, 1922, to the Dakota Radio Apparatus company, and is the oldest surviving radio station in the state of South Dakota. The call-letters came from a sequentially assigned list, and WNAX was the last station in the state to receive a callsign starting with a W instead of K (other than sister station WNAX-FM), as additional stations in the state were established after the January 1923 shift that moved the K/W call letter boundary from the western border of South Dakota to the Mississippi River. WNAX was purchased by Gurney's Seed and Nursery Company in 1926 and became known as "WNAX—Voice of the House of Gurney in Yankton". The station was used to promote Gurney products and services, making Gurney's a household name. On February 10, 1933, the Federal Radio Commission authorized an increase in daytime power from 1,000 watts to 2,500 watts. Less than two years later, December 18, 1934, the new Federal Communications Commission (FCC) authorized another increase in power, to 5,000 watts. The radio station launched the careers of many stars, both local and national. Starting in the late 1920s, Lawrence Welk spent a decade performing daily without pay on WNAX. In 1939, Wynn Hubler Speece started her radio program