the australian broadcasting commission commenced its youth radio service in 1975 utilising a standby transmitter at the pmg's department liverpool am transmission facility. with a modest power, higher frequency allocation and noisy radio environment, coverage was limited to a portion of the sydney metropolitan area. the allocated callsign was 2jj, but in an early usage of on-air identifiers it was soon announced as simply double j. the service was immediately popular and demand for better coverage and transmission quality was strong. in one of the earliest examples of amfm conversion in australia, the station was authorised to convert to the fm radio band in 1980, together with high power and full metropolitan coverage. the callsign became 2jjj and the on-air identifier just triple j. popularity continued to soar and the program stream was deployed to new fm transmitters in the capital cities in 1989 (tranche 2), then many regional areas in the early 1990s (tranche 3). as the abc's focus became increasingly content creation, further extension of the network by the abc itself has ceased, but the network continues significant expansion throughout australia by means of privately funded retransmission licences (enabled by the bsa92). in newly established mines, a triple j fm transmitter to entertain the community is often the first choice for establishment.