The station began life as 4BK, commencing transmission in 1930 on the
AM band, initially on the frequency 1290 kHz before changing to 1300 kHz on 1 Sep 1935 (to accord with the new Australian 10 kHz channel spacing raster). Again the implementation by Australia of the 9 kHz channel spacing raster developed by the ITU and formalised in the
1975 Geneva Plan necessitated 4BK moving to 1296 kHz on 23 November 1978. In 1988, the
Austereo group purchased the station from
Hoyts, intending to use it as a vehicle to bid for an FM conversion licence. Austereo won the FM licence, and in February 1990, the station changed its callsign to 4BBB (not used on-air except during test broadcasts, unlike the previous AM callsign) and commenced broadcasting on a frequency of 105.3
MHz with the on-air name
B105. Between March 1990 until 2006 it was the highest rating station in Brisbane, except in one ratings survey in 1994, beaten by AM station
4KQ. In April 2011 the Austereo Group was purchased by
Southern Cross Media for more than $700 million, and is now operated under the name
Southern Cross Austereo. On 6 March 2015, B105 rebranded as Hit 105. On 27 July 2020, Hit 105 rebranded back to B105. ==Studios==