All most right. According to CASA there are 7 situations where you are expected to broadcast your intentions to make sure you comply with the MINIMUM requirements of CAR166C
1 before, or during taxiing
2 immediately before entering a runway
3 inbound 10nm or earlier from aerodrome
4 immediately before joining circuit
5 on a straight-in approach, on final,by 3nm from threshold
6 on a base join approach, before joining base and
7 on entering the aerodrome vicinity of a non towered aerodrome, where you intend to fly through the vicinity but not land