WMBX (102.3 FM, "R&B X 102.3") is a radio station serving the West Palm Beach, Florida and Port St. Lucie, Florida areas, broadcasting an Urban Adult Contemporary format. Its antenna is located on the west side of Jonathan Dickinson State Park in Hobe Sound, Florida and is 965 feet height above average terrain. Also sharing WMBX's transmitter tower are stations WIRK and WKGR. WMBX transmits at 100,000 watts effective radiated power, making it sometimes able to be picked up as far south as Miami, as far north as Cocoa Beach and as far west as Moore Haven. WMBX is owned by Alpha Media, through licensee Alpha Media Licensee LLC. Its studios are in West Palm Beach.
X 102.3 launched on October 23, 2001 (10/23 - 102.3). From 1997 - 2001, the station played an Adult contemporary format, under the branding Mix 102.3. The station hosted its first concert on November 6, 2009 at the South Florida Fair Grounds titled X-Fest 2009. Acts included Clipse and Mario.
In 2006, R&R moved WMBX from the Rhythmic panel to the Urban panel, but in May 2007, R&R moved the station back to the Rhythmic panel due to a shift in its direction which now favors a broader Rhythmic playlist.
On April 10, 2012, CBS Radio announced that it was selling WMBX and its sister stations to Palm Beach Broadcasting for $50 Million, pending FCC approval. The station's Rhythmic format and airstaff will be retained under the new owners. After sister station WUUB (B106.3) dropped its adult R&B format in February 2013 to become the West Palm Beach affiliate of ESPN Radio upon being sold to Good Karma, WMBX gravitated its direction to the broader urban contemporary format and added more R&B to its playlist.
On May 13, 2013, WMBX began airing the Steve Harvey Morning Show weekdays from 6:00 to 10:00 a.m., using Reggie Dee to provide local content during breaks.
Effective February 25, 2016, Digity, LLC (parent company of Palm Beach Broadcasting) and its 124 radio stations were acquired by Alpha Media for $264 million.