Complex sentence: It was launched in 4 April 1983 by Frank Muir as County Sound Radio (back then on 203 MW and 96.6 FM), in 1986 the FM frequency was changed to 96.4 FM.
Split into simpler sentences: It was launched on 4 April 1983 by Frank Muir as County Sound Radio on 203 MW and 96.6 FM. In 1986 the FM frequency was changed to 96.4 FM.