The station originated in 1933 as CRCS, owned and operated by the Canadian Radio Broadcasting Commission and based in Chicoutimi (which became part of Saguenay in 2002). It became CBJ when the CRBC became the CBC. Originally located on the AM band on 1580 kHz, the station moved to FM in 1999. The AM signal was a 50,000-watt clear channel station from 1977 onward, and was well known as an extremely reliable DX signal at night, It was often used by people who wanted to receive Première Chaîne when they were traveling just about anywhere in the eastern half of North America. The frequency has not been reactivated, nor has it been applied for, in Saguenay.
Because of deficiencies with the main FM signal which did not exist when the station was on AM, CBJ-FM operates a relay, CBJ-FM-6, to serve nearby La Baie, now part of Saguenay. That relay is one of the few co-channel relays used in Canada, meaning that it is also broadcasting on 93.7 MHz; this solution was chosen to permit people to listen to the station in their cars continuously between Chicoutimi and La Baie without having to switch to a new frequency, de facto extending the main signal of CBJ-FM. CBJ-FM-6 operates using a directional antenna with an average effective radiated power of 16 watts and a peak effective radiated power of 86 watts (class A1).
Other relays operated by CBJ-FM include the following :
CBJ-FM-1 in Chibougamau, broadcasting on 91.9 MHz with an effective radiated power of 420 watts (class A) using an omnidirectional antenna;
CBJ-2 in Chapais, broadcasting on 1140 kHz with 40 watts full-time (class LP) using an omnidirectional antenna;
CBJ-FM-3 in Dolbeau-Mistassini, broadcasting on 93.1 MHz with an effective radiated power of 38,200 watts (class B) using an omnidirectional antenna;
CBJ-FM-4 in L'Anse-Saint-Jean, broadcasting on 101.9 MHz using a directional antenna with an average effective radiated power of 510 watts and a peak effective radiated power of 970 watts (class B1); This replaces the original AM transmitter that went on the air in the mid 1980s.
CBJ-5 in Petit-Saguenay, broadcasting on 1140 kHz with 40 watts full-time (class LP) using an omnidirectional antenna. Its uncertain if this transmitter is still in operation, however, the CBC received CRTC approval in 2003 to cease operation of the CBJ-5 transmitter after CBJ-FM-4 signed on the air in L'Anse-Saint-Jean.