Upon opening in , 3DB broadcast on the AM band at a wavelength of metres, corresponding to a frequency of kHz. In the s, at most stations including 3DB, it was not unusual for there to be breaks between programs during which the station temporally closed down. Sometimes these breaks were of 30 minutes' duration; sometimes longer. By , 3DB was on air at the following times:. Between Amateur radio stations which normally broadcast on the shortwave band were permitted to use the medium wave AM band. This arrangement appears to have been exclusive to Melbourne.