KJXK (102.7 FM, "102.7 Jack FM") is a commercial radio station in San Antonio, Texas, broadcasting an adult hits radio format using the "Jack FM" brand. It is owned by Alpha Media with radio studios on Eisenhauer Road in Northeast San Antonio. KJXK has an effective radiated power (ERP) of 100,000 watts, currently the maximum for American FM stations. The transmitter is atop Tower of the Americas in downtown San Antonio, off Cesar Chavez Boulevard. History Progressive Rock 102.7 had its initial construction permit issued on November 20, 1967, as the FM counterpart of KTSA 550 AM. On June 7, 1968, it was given the call sign KTSA-FM, which was shortened to KTFM prior to sign-on. KTFM officially went on the air for the first time on . It was originally owned by Waterman Broadcasting of Texas and it largely simulcast KTSA. In 1972, management to switch KTFM to progressive rock. This format lasted until 1976, when it shifted towards a more structured album rock format, playing the most popular tracks from top selling albums. Top 40 In 1980, the station dropped its album rock format for Top 40/CHR. Its Top 40 format would later evolve into a Rhythmic Top 40 formula in late 1988. KTFM was one of three dominant Top 40 stations in San Antonio, competing with the other two dominant CHR stations, 96.1 KSAQ (now KXXM) and KITY “Power 93” (now Regional Mexican "Que Buena" KROM 92.9). In March 2000, Waterman reached a deal to sell KTFM and KTSA to Infinity Broadcasting for $90 million, as Waterman was looking to focus solely on its television assets. That same year, the Top 40 market would be shaken up by the arrival of a move-in at the 98.5 FM frequency. KBBT was launched as "The Beat", with a Rhythmic format featuring hip-hop music. The Beat quickly climbed up in the ratings. In August 2001, KTFM decided to challenge KBBT by changing from Mainstream Top 40 to a more rhythmic-leaning sound as "Wild 102-7". KBBT had the hip hop audience, and KTFM started to see its ratings decline. K-Rock and Jack FM On October 24, 2003, KTFM dropped the Top 40 format after 17 years and flipped to Mainstream rock as "102.7 K-Rock." The call letters became KSRX. The first song on "K-Rock" was "Welcome to the Jungle" by Guns N' Roses. But 99.5 KISS-FM was the veteran rock station