WMFN (640 AM) is a radio station broadcasting a Spanish Contemporary music format. The station is known on-air as "Radio Activa." The station is owned by Birach Broadcasting. Licensed to Zeeland, Michigan, it first began broadcasting in 1990 under the WBMX call sign, and has been through a number of different formats and call signs since, including the Radio AAHS children's format, mainstream talk, sports talk and most recently (prior to the current format) Regional Mexican. During its sports talk days former NFL great Ray Bentley hosted his own afternoon program.
AM 640 was originally a MOR station in 1990 when it signed on as WBMX, using the call sign that had recently been vacated by a popular urban contemporary station in Chicago, Illinois. The following year, the owners of WROR-FM 98.5 in Boston, Massachusetts, bought the WBMX call letters from AM 640 in order to debut "Mix 98.5" there; in return, AM 640 received the WROR calls. Its format did not change. In 1993, WROR-AM was sold and converted to Radio AAHS as WISZ, freeing the WROR calls to be used again in Boston, where they were again placed beginning in 1996.
For a time, the station also played adult standards ( Westwood One's AM Only) at night as a continuation of daytimer sister station WMJH 810 AM's format. Since WMJH was known at the time as "Majic 810," WMFN's nighttime standards programming was called "Night Majic."
In 1995 am 640 became WMFN, taking a sports format branded "West Michigan's Fan". In 1999 WMFN adopted a Business News format branded "West Michigan's Financial News". Starting in 2000 WMFN evolved into a News Talk Sports format eventually becoming "Hot Talk 640". In 2005 WMFN's talk format was dropped in favor of an Adult Urban Contemporary format branded "Smooth Vibes AM 640".
From about 2006 until November 2008, the station was leased to Tyrone Bynum, a controversial talk show host and deejay who hosted many of his programs on this station, which went under the name "Smooth Vibes"; during periods when there was no talk programming, Bynum (or his staffers) would play Urban Adult Contemporary music.
In November 2008, due to low advertising revenues, Bynum opted not to renew his lease with Birach; on November 7, 2008, the station began carrying Regional Mexican programming, moved from WMJH. Bynum soon relaunched "Smooth Vibes" as an online-only station free from music licensing fees.
As "La Poderosa," the station became the exclusive Regional Mexican station in West Michigan, as former competitor stations WYGR and WNWZ have switched to other formats. The "Poderosa" format has since moved back to WMJH, which has also launched an FM translator at 93.3. At that time, WMFN became Radio Activa.
During daytime hours, WMFN is heard as far away as Chicago, Illinois and Lansing, Michigan. 1
In 2014, the FCC allowed the station to shut down so Birach can sign on another radio station at 640 AM outside Chicago, to be licensed to the town of Peotone, Illinois.