|City of license||Tijuana, Baja California|
|Broadcast area||San Diego-Tijuana|
|Slogan||"Local. Independent. Radio."|
|First air date||1978|
|Sister stations||XHITZ, XHRM|
|Webcast||Flash Player, PLS|
XETRA-FM (91.1 FM) — branded 91X, and sometimes identified as XTRA-FM — is an English language, Mexican-owned (border blaster) modern rock music station broadcasting from Tijuana, Baja California on 91.1 MHz. The studios are located in the Mira Mesa area of San Diego. The station is one of three outlets that are programmed by Local Media of America, who took over the operations of XETRA-FM from Broadcast Company of the Americas in 2010.
91X was formed in 1978 and signed on with an AOR format. It remained until 1983. 91X broadcast studios were located at the 91X transmitter site on Mount San Antonio in Tijuana. Initially, programming was recorded at the San Diego Studios in the Harcourt, Brace, Jovanovich building downtown and driven to the transmitter site several times a day. That proved not to be competitive. . Disc jockeys then commuted from San Diego to Tijuana each shift. 91X was notorious for having DJs with no personality; they would simply announce the previous song, and the next song. On January 11, 1983 at 6PM, 91X followed in the footsteps of KROQ-FM and switched formats to "rock of the 80s" (modern rock). 91X played "Stairway to Heaven" (Led Zeppelin) as the final song of the AOR format. Immediately afterward, then 91X Executive Vice President and General Manager John Lynch made on air announcement of the format change and disc jockey Todd Ralston went right into "Sex (I'm A...)" by Berlin. Former 91X on-air personality Jim LaMarca recounts the transition:
- "The day 91X (XETRA-FM) went Rock of the 80s, almost no one knew it was coming so there was no speculation. An air staff meeting was called for 3pm. These really straight liner-card jocks were sitting around the conference room when in walks wild Rick Carroll with a cardboard box. He dumps it on the table and says, 'I'm Rick from Los Angeles and this is your new format.' The first song was played at 6pm by Todd Tolkoff who was given the name Mad Max. He said, 'This is 91X Rock of the 80s and this is "Sex" from Berlin.' Everyone at the station (remember he is now in Mexico 30 minutes away) thought this song was too weird. It seemed slow and goofy, but hey this was all new to us. It also took forever. Well no wonder, he was playing a long-play version so the LP should have been playing at 45 rpm. Since we had never heard the song no one knew. This happened a lot." 
During the 1980s and 1990s 91X was one of the top-rated alternative stations in America. 
U.S. marketing and operating rights
On December 1, 2005, Clear Channel Communications was forced to spin off the U.S. rights to program and sell advertising time on XETRA-FM, XHITZ-FM (90.3) and XHRM-FM (92.5). This was an effort to satisfy existing consolidation laws. Stations based in Tijuana, Baja California and operated by U.S. broadcasters are now considered as part of the San Diego radio market for ownership limit purposes. The Mexico-based stations put Clear Channel over the Federal Communications Commission (FCC) limit of eight local broadcast outlets in San Diego.  Clear Channel operates seven stations in the San Diego market.
Finest City Broadcasting, a new company under the direction of former Clear Channel/San Diego VP/Market Manager Mike Glickenhaus, took over operations of the three stations. Glickenhaus left FCB in May 2007, and is not involved in radio as of December 2007.
In December 2009, Finest City, faced with massive debt and foreclosure, put the entire cluster up for sale. On January 7, 2010, Broadcasting Corporation of the Americas, whose owner John Lynch was also XETRA's VP/GM in its early days, emerged as the buyer in a foreclosure sale. John Lynch is the father of John Lynch (American football).
John Lynch, dba Noble Broadcast Consultants, also owned and operated XTRA AM 690 (69 XTRA Gold) which shared staff and facilities with 91X. In addition, the Sunday morning oldies format was programmed by AM Program Director Jim Lamarca. Clear Channel formerly owned the U.S. programming and sales rights to that station as well, and spun those rights off to a different operator.
On December 27, 2007 Chris Cantore confirmed with SDRadio that he was let go from the alternative rocker after a decade of service.
On April 1, 2008 "The 91X Morning Show" debuted after a month-long marketing campaign that centered around the question "who is Mat Diablo?". On May 7, 2010 the 91X Morning Show was canceled after 91X was purchased in a foreclosure sale.
"Music In The Morning" is hosted by Oz Medina, who previously worked as 91X's Music Director & Afternoon Host from 1987-1993.
91X's Music Director is Christy Taylor, who handles Nights on-air.
Up until January 2012, 91X carried the syndicated Loveline weeknights. No reason has been given for the change.
Until 2008, 91X aired Reggae Makossa, a program featuring reggae and roots music that now airs on Fusion Radio 102.5. The program was originally hosted by Makeda Dread and Demaja Le. Demaja Le left in 1998 to program Jazz 88.3. Makeda Dread still hosts the show in its new location. Despite the move, 91X still plays occasional reggae music, most notably daily around 4:20 pm to honor 420.
Under the rules and regulations of the Secretary of Communication and Transportation of Mexico, 91X (and other Baja California, Mexico-licensed stations) concludes its broadcast week with public affairs and other mandatory programming in the Spanish language Sunday evenings beginning at 10 p.m. Pacific time.
Current and Former on-air staff
- Juan Grande (daily surf report since 1983) died September 16, 2006 
- Billy Bones
- Steve West (On air 1983 - 1996, 1998 - 2008) Middays and Resurrection Sunday, laid off in November 2008, re-hired November 2010 to present.
- Chris Cantore ([Cantore in the Morning] 91X DJ from 1997–2007) now at KPRI / San Diego)
- Clint August (formerly Clint the Morning Show Tool with Chris Cantore, now on Rock KIOZ 105.3)
- Ruggy- Currently Community Manager for Yelp, Inc.
- Diana D'Amato
- Stephen Kallao (now at WYMS / Milwaukee)
- Michael Boss
- Marco Collins (now a KEXP / Seattle)
- Todd Ralston
- Sue Delaney
- Scott Avery (later went to KBEST-95)
- Reckless Erik Thompson (now a TV network announcer)
- Jim Gelaro
- Mike Halloran
- Hilary (now works at FM 94/9.)
- Jennifer White (now at Radio Sophie)
- Jeff Hunter
- Bryan Jones (born October 13, 1957, died November 15, 2006 )
- Dean Opperman
- Katy Manor
- Kevin "the Dead Dog Kid" Stapleford (former Director of Content Development & Programming at Tapioca Mobile and currently Director of Network Operations at X1FM Network www.x1fm.com)
- Gene Knight (now with KYXY)
- Jim Lamarca [EVP/COO Jones Radio Network]
- Matty (now in Oregon working with the Democratic Party)
- Lani Minella
- Bob Montague
- Russ T Nailz
- Mike Berger
- Jeff Prescott 
- Jason Riggs (currently Senior Product Manager at Qualcomm and Program Director for the 80s Alternative radio station on Slacker.com)
- Lou Niles
- Deirdre O'Donoghue (1946–2001; hostess of 91X's S*N*A*P Judgements radio show)
- Tom Perry
- Trever Trent (now works at 98.7FM KYSR Los Angeles/101.5 KGB San Diego)
- Craig "Just Craig" Herdrich
- Rick Savage (now works for KROQ 106.7)
- Bryan Schock (now works at 101.5 KGB)
- Todd "Mad Max" Tolkoff (program director of now-defunct Indie 103 in Los Angeles, California)
- Pam Wolf
- Lindy Scott
- Jay Peterson
- Robin Roth
- "Rossman" Ross Shields
- Marty Whitney (currently Live Sound Engineer and Imaging Director for Alice@97.3 KLLC in San Francisco)
- Annrae Fitzgerald (currently Network Program Director, X1FM San Diego)
- Chris Muckley (On air 1995 - 2009, Music Director 1996 - 2003, Resurrection Sunday Nov 2008 to 2009. Now is on KCRW Los Angeles and still does some guest spots on 91X)
- Matthew "Mat Diablo" Bates (91X Morning Show) Currently Sr. Radio Program Manager for Slacker (music service)
- Jason Mahoney (91X Morning Show) Currently Morning Show Host of the 'The Dave and Mahoney Morning Show' on KXTE in Las Vegas, Nevada
- Carlos Montoya (91X Morning Show) Currently Executive Producer of the 'Scott and BR" radio program on XEPRS-AM
- The Official Website
- 91X on Twitter
- Pictures of the XETRA-FM transmitter site on Mt. San Antonio
- 91X top 91 countdowns plus a searchable archive
- Finest City Broadcasting (Former owners)
- Audio of 91X IDs from 1984-1989
- "Local Media of America acquires Finest City Broadcasting in Foreclosure Sale". Retrieved 22 May 2011.