Complex sentence: The primary station, WBRA-TV (channel 15) in Roanoke signed on for the first time on August 1,1967, originally affiliated with the National Educational Television (NET), before that organization was replaced by PBS in 1970.
Split into simpler sentences: The primary station, WBRA-TV (channel 15) in Roanoke signed on for the first time on August 1,1967. It was originally a member of National Educational Television (NET), before that organization was replaced by PBS in 1970.