WTTO, virtual channel 21 (UHF digital channel 28), is a FOX-affiliated television station serving Birmingham, Alabama, United States that is licensed to the suburb of Homewood. Owned by the Sinclair Broadcast Group, it is a sister station to WB affiliate WBMA-LD (channel 58) and UPN affiliate WABM (channel 68), both licensed to Birmingham. The three stations share studios at the Riverchase office park on Concourse Parkway in Hoover (with a Birmingham mailing address); WTTO's transmitter is located atop Red Mountain, near the Goldencrest neighborhood of southwestern Birmingham.
WTTO operates a full-time satellite station, WDBB (virtual channel 17; UHF digital channel 18), licensed to the Birmingham suburb of Bessemer. It is owned by Cunningham Broadcasting and operated by Sinclair under a time brokerage agreement (TBA); however, Sinclair effectively owns WDBB as the majority of Cunningham's stock is owned by the family of deceased group founder Julian Smith. WDBB—whose transmitter is located east of State Route 69, near Windham Springs—relays WTTO's programming to areas of west-central Alabama that receive marginal to non-existent over-the-air coverage from the latter station's main signal (including its primary city of service, Tuscaloosa). However, there is a decent degree of overlap between the respective signal contours of WTTO and WDBB in western portions of the Birmingham metropolitan area. On-air references to WDBB are limited to FCC-mandated hourly station identifications during station promotions and regular programming, with both stations using WTTO's virtual channel number in on-air branding.
The main WTTO signal is distributed to cable providers throughout most of the Birmingham–Tuscaloosa–Anniston market from Jefferson, Tuscaloosa and Shelby counties northeastward, while its programming is available to providers southwest of that line via WDBB. In Birmingham, the station is available on Comcast Xfinity channel 4, Charter Spectrum channel 9 and AT&T U-verse channel 21.