On August 20, 1963, Commercial FM Radio came to Lawrence as KLWN-FM first signed on. The station was built in order to have a full-time signal to broadcast sports and other information, including things like school closings, as the AM station was limited to daytime hours. Because sunrise is at 7:45 AM during the winter, school closings could not be disseminated to the public in a timely fashion via the AM station. Hank Booth, longtime General Manager, had commented that the FM was originally run by a tape, and that no one listened until it was time for KU or Lawrence High Football.
The station started with technical facilities of 17 kW on 105.9 MHz. From 1963 to 1974, both stations shared the same studio. KLWN-FM essentially simulcasted the AM during daylight hours until 1972. In 1972, the staff began a separate rock programming in the overnight hours, first after the AM sign-off, then it was pre-taped and replayed the next day at 3 PM, later noon. On April 1, 1974, an addition to the station allowed the AM to move into a new studio (complete with an interview room) and the FM to have the old one. On July 31, 1979, KLWN-FM received the new calls of KLZR and was authorized to increase power to 100 kW. The new 550-foot tower was completed and the new transmitter was put in use in December.