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|City of license||Brisbane, Queensland|
|Broadcast area||Brisbane RA1 ()|
|Slogan||"Brisbane's '#1 Hit' Music Station"|
|Frequency||105.3 MHz FM (also on DAB+)|
|First air date||September 29, 1930
February 26, 1990 (FM)
|Format||Top 40 (CHR)|
|Former callsigns||4BK (1930-1990)|
|Former frequencies||1290 kHz (1930-1935)
1300 kHz (1935-1978)
1296 kHz (1978-1990)
|Owner||Southern Cross Austereo
(Today FM Brisbane Pty Ltd)
The station now known as B105 began life as 4BK, commencing transmission in 1930 on the AM band, initially on the frequency 1290 kHz before changing to 1300 kHz in 1935. The introduction of 9 kHz spacing on the AM band led to 4BK moving to 1296 kHz in 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, 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.
The 4BK studio complex, an AM radio facility was located at 16 Campbell Street Bowen Hills. When the FM conversion license was granted, the Austereo group converted the premises to an FM facility and began broadcasting as B105 FM in 1990.
The B105 FM studio complex remained at the Bowen Hills location until July 2000, when Austereo relocated B105 and sister station Triple M into new combined premises at 309 North Quay, Brisbane. The new complex was the first in Australia to use the now defunct Klotz Digital audio system, which was revolutionary at the time.
B105's FM transmission has always emanated from the TVQ Ten tower at Mount Coot-tha, Brisbane. The station originally used two Harris HT10 tube transmitters in an A/B failsafe configuration to deliver the service. In 2002 a new solid state Harris Z10CD transmitter was installed at the newly created TX Australia facility, located under the TVQ Ten tower. The existing HT10 transmitter now serves as a backup facility located at the BTQ Seven tower, 1 km away from Channel Ten on Mount Coot-tha.
B105's FM service is licensed for 12Kw Effective Radiated Power at the antenna, and operates its transmitters at 5Kw base power.
B105 and Southern Cross Austereo's DAB services all emanate from the TVQ Ten tower on combined equipment used by all radio broadcasters in Brisbane.
Former B105 announcers 
Digital radio 
B105 is simulcast on Digital Radio in Brisbane.