According to the ACMA, one tower is used by AirServices, in the UHF and microwave bands, the other tower is used by the BoM, PowerCor and Western Comms, both private companies... If you plug these numbers: -37.762608, 144.622526 into
this website, it'll take you to the ACMA database of transmitters, and from there your own Google-fu should be adequate if you are still curious.