Complex sentence: KQHT began as a Top 40 station in 1986 as "Magic 96" competing with XL93 until 1998 when it changed to an adult contemporary format branding itself as "KQ96" in 1996, and rebranded as "Mix 96.1" in 1998.
Split into simpler sentences: KQHT began as a Top 40 station in 1986 as "Magic 96" competing with XL93. It renamed itself "KQ96" in 1996, and "Mix 96.1" in 1998.