Radio KSZR-FM (97.5 Bob FM)

KSZR (97.5 FM, "Bob FM") is an adult hits formatted radio station serving Tucson, Arizona, USA. It is licensed to broadcast from Oro Valley, Arizona, (a northern suburb of Tucson), but its reception is generally above average in most areas of Tucson. It is owned by Citadel Broadcasting Corporation. The station is focused on '70s and '80s rock and adult contemporary music. KSZR plays current pop and modern rock as well.

KSZR has gone through a variety of format changes in the past. Its first days on the air as KRKN were as a satellite based rock station.

In 1994 KRKN's call letters were changed to KCDI. As KCDI, the station was known as "CD Country" and played satellite delivered country music.

In 1996 KCDI became KSJM, and was known as Power 97.5. Power played a mix of hip hop, Spanish, and Top 40 music, (today's Rhythmic Top 40) and received high ratings, which competed with KOHT.. Power was the first station in Tucson to play Rhythmic Top 40 over the FM airwaves.

After about two years, Citadel purchased the station from locally owned Slone Broadcasting. In 1998, Citadel turned Power 97.5 to a smooth jazz station. It was known as 97-5 The Oasis. The call letters became KOAZ.

Due to low ratings and a lack of interest, the smooth jazz format was scrapped for a Country format known as "Cat Country" in 2001. This seemed to be a response to Clear Channel Communications' addition of a country station to Tucson, 92.9 Coyote Country (KOYT)(Today's KWMT-FM). Clear Channel's plans in creating Coyote Country were to take away enough listeners from long-dominant KIIM-FM 99.5 (who coincidentally enough is also owned by Citadel), who has consistently been number one in the Tucson Arbitron ratings. Both Cat Country and Coyote Country failed.

The station then changed to "Star 975" in 2002, a mix of pop, modern rock, and adult contemporary. The call letters became KSZR, and this format went on the longest. Ratings still failed to make a considerable difference, and Star 975 failed.

In November 2004, Citadel Broadcasting Corporation changed Star to BOB FM, an adult contemporary / variety hits format. KSZR is currently still BOB FM. But based on still lacking ratings, there are various rumors that it will change to a talk format which is more common on AM radio.[citation needed]