OK, I admit it; being an accountant I happen to like the asthetic beauty and the inherant design of numbers; including 666 - the number of the Beast. There are various interpretations as to what it means or why it's in there and whilst I remain totally confused on the issue I will continue remain silent on theories and postulations. However...
666kHz just happens to be the radio frequency for 2CY (ABC Local Radio) in Canberra.
When 2JJ vacated the 1540kHz frequency, the ABC decided that a re-transmission of the NSW broadcaster 2FC (internally called NSW Radio 1) was in order. 2CY remained on the 1540kHz frequency until 1983 when it took up the longer wave frequency 666kHz to improve reception for the immediate areas; then when ABC Local Radio became fully integrated it re-branded itself.
Consider what the frequencies used to be before 9kHz cycling for digital tuning:
It made sense therefore for 2CY to be 666kHz. Other ABC stations had been deliberately cast with memorable numbers; it's just a wee bit ironic that the Devil's number should be the ABC in the nation's capital.