following establishment of the australian broadcasting control board in 1948, it was decided to focus the development of commercial radio services in australia upon increasing the power and coverage of the existing services. during the 1950s the sydney and melbourne commercial services were permitted to increase power from typically 2 kw to 5 kw with modest coverage increases. concurrently many regional commercial services, some with powers as low as 200 watts, through carefully planned sequences of frequency changes, were able to effect power increases to typically 2 kw.