103.9 LOS40 (San Luis Potosí)

LOS40 103.9 (XHEWA-FM 103.9 / XEWA-AM 540) is a commercial radio station in San Luis Potosí, Mexico, carrying the Top 40 (CHR) format Los 40 with Spanish and English language hits. It is owned by Radiópolis. XEWA-AM is one of the highest powered radio stations in North America, broadcasting at 150,000 watts with a directional antenna by day and a non-directional antenna at night from Soledad de Graciano Sánchez; the FM operates with 25,000 watts from the same area.

XEWA received its concession on December 2, 1948, one of a string of repeaters of XEW-AM 900 Mexico City authorized in the late 1940s. It began on 540 kHz with 150,000 watts — still its current levels — making it the most powerful AM station in the country. On March 16, 1988, XEWA adopted a grupera format called Súper Estelar WA, programmed from Monterrey by Multimedios Estrellas de Oro and one of Mexico's pioneering grupera stations; after five years, the format moved to XHSNP-FM in San Luis Potosí.

The station then flipped to the Ke Buena format from Radiópolis until 1998, when it began repeating XEW again, known first as Cadena W Azul y Plata and later as W Radio. In 2003, Radiorama began managing the station for Televisa Radio. In July 2009, XEWA Monterrey and XEWA San Luis Potosí split for the first time, with the San Luis Potosí station transferred to MG Radio.

XHEWA-FM 103.9 was authorized in 2011 and came on the air that July; while technically an AM-FM migrant, the AM station cannot be shut off until radio service reaches its entire coverage area. In 2012, Radiorama returned to manage XEWA/XHEWA, and in July W Radio was replaced with Los 40 Principales. Grupo AS operated the region in 2016, and on January 9, 2017, GlobalMedia took over operations of XHEWA.