I’ve got the Sydney radio ratings from that time. They made its debut on Survey 4 of 1980.
Here are the ratings from that survey:
#1 2UE: 19.2
#2 2CH: 15.5
=#3 2SM: 11.6
=#3 2WS: 11.6
#5 2BL: 8.8
#6 2UW: 8.3
#7 2GB: 6.0
#8 2MMM: 2.6
#9 2DAY: 2.0
#10 2JJJ: 1.2
And Survey 1, 1981:
#1 2CH: 17.7
#2 2UE: 16.5
#3 2UW: 15.9
=#4 2SM: 8.5
=#4 2WS: 8.5
#6 2BL: 8.1
#7 2MMM: 5.2
#8 2GB: 5.0
#9 2JJJ: 2.9
#10 2DAY: 2.4