KRTH (101.1 FM, "K-Earth 101") is a U.S. Classic Hits radio station located in Los Angeles, California, broadcasting to the Greater Los Angeles Area. Its signal covers an extremely large area, due in part to their antenna location on Mt. Wilson, and can sometimes be heard as far south as San Diego and Tijuana, as far east as Moreno Valley, as far west as Santa Barbara and as far north as Baker, California. The station has studios on Wilshire Boulevard in the Miracle Mile district of Los Angeles.
KRTH signed on August 11, 1941 as the first FM station in Los Angeles. The station's original call letters were K45LA, broadcasting on 44.5 Megacycles from a tower atop Mount Lee. After World War II, when the FCC mandated the 88-108 Mc. range, the station was moved to 99.7 Mc., and the call letters were changed to KHJ-FM, after its then-sister AM station KHJ. In 1948, KHJ-FM moved yet again to its current broadcast frequency of 101.1 FM, eventually relocating its transmitter to Mount Wilson.
In 1965, when KHJ switched to top-40 format "Boss Radio", they simulcasted on KHJ-FM. From 1968-70, KHJ-FM aired Drake-Chenault's "Hit Parade" format, an automated mix of oldies and current hits. In 1971, the station carried another Drake-Chenault top-40 format, "Solid Gold Rock And Roll."
In 1972, there was a switch to what was then called a "gold" format, featuring older hit songs from the past. At the time, this was a novel idea since most stations played current music, with a few older songs mixed in. With the switch in format came a new moniker, "K-Earth," which was named after the first "Earth Day" which had debuted to much fanfare two years before. The call letters were thus switched to KRTH. The "K-Earth 101" jingle was also introduced at this time. It directly echoed the sound and notes of the jingle from KHJ-AM, the station where many of these "gold" songs had originally been played. (KHJ-AM was still on the air at this point, but was playing current Top 40 songs.)
During the 1970s and early 1980s, K-Earth vacillated between this "gold" format and an adult contemporary format. Current music was played to varying degrees throughout this period, though the focus was almost always on the past.
In 1985, K-Earth shifted to what was becoming known as an "oldies" format, adopting the motto "Classic Rock and Roll." KRTH began promoting its "Good Time Oldies" image with frequent TV ads featuring Beach Boys music, classic cars, palm trees, and the ever present K-Earth jingle. The songs featured were from 1955–1984, though the focus was largely on the late 1960s and early 1970s. Doo-wop, early rock, Motown, girl groups, Elvis Presley, and The Beatles were the mainstays of the station's music mix. Throughout the 1980s, K-Earth would feature huge weekend specialties, including #1 music over the Labor Day Weekend. Every L.A. #1 song would be played in chronological order (utilizing the older KHJ Boss 30, KFWB Fab Forty and other local charts) from 1955 through 1985. The weekend before would feature the "Runner's Up of Classic Rock and Roll Weekend", the #2's. The Firecracker 300 was played over the 4th of July Weekend. Other specials included a Memorial Day Weekend A to Z, the "Super Sixties Weekend" and the "Souvenirs of the Seventies Weekend". The station was sold to Beasley Broadcasting in 1988.
Oldies were a ratings success for KRTH, and for similar stations across the United States and Canada. In March 1989, another Los Angeles FM oldies station emerged at 93.1 under the call sign KODJ, and later as KCBS-FM as a direct competitor with KRTH. KODJ/KCBS-FM played oldies from 1955 to 1972 with a heavy focus on pre-1964 oldies. KRTH continued acknowledging the mid and late 1970s and continued playing moderate amounts of pre-1964 material until 1991, when management eliminated the 1980s' music and most post-1972 songs. The two stations went head-to-head for a few years, with K-Earth consistently getting higher ratings and emerging as the winner. KODJ even changed its call letters to KCBS-FM, and in early 1993, began playing mostly pre-1965 oldies. KCBS-FM successfully switched to a classic rock format in the fall of 1993 called "Arrow 93," but today offers an adult hits format called Jack FM. KRTH, by then, focused on the 1964 to 1969 period with moderate amounts of pre-1964 material and 1970s songs each hour. The station remained a competitor with Pasadena’s AM oldies station KRLA until 1998, when KRLA switched formats. KRTH was sold to Infinity Radio in 1994. Infinity was purchased by Westinghouse (then-owner of CBS) in 1997, making KCBS-FM (by then Classic Rock) and KRTH sister stations. In 2002, the station would be reunited under common ownership with the former KHJ-TV when CBS bought KCAL.
From 1992 to 1997, K-Earth was once home of Robert W. Morgan and The Real Don Steele, who were co-workers at KHJ during the 1960s Boss Radio era. In May of 1997, Morgan announced in the on-air emotional statement that he had lung cancer, which lead to both his retirement and took his life by mid-1998. Steele also died from the same disease in August of 1997, marking the end of boss radio. Shotgun Tom Kelly would replace Don Steele in the afternoon drive spot from 1997-2015.
K-Earth continued with its oldies format throughout the 1990s. Toward the end of the decade, older songs from before the British Invasion of 1964 were increasingly dropped from the playlist, and the station began to showcase the late 1960s, especially Motown music, to a much greater degree. The playlist itself began to shrink, with only the biggest, most-requested hits from this period played in heavy repetition.
With its demographic aging and ratings sagging, K-Earth, along with most oldies outlets across the country, began adding 1970s songs into the playlist in the early 2000s. Artists such as Stevie Wonder, Elton John, ABBA, the Bee Gees, Earth, Wind & Fire, and Peter Frampton were combined with 1960s artists such as The Supremes and the Beatles. Though still repetitive, the playlist was also rotated a bit more, with a few rediscovered oldies brought "out of the vault" on occasion, while other songs were "rested" from the rotation. This process was taken a step further in 2007 with a few early 1980s' songs added to the mix by artists such as Hall & Oates, Phil Collins, and Michael Jackson.
Whether by luck, or due to the musical changes implemented, by the end of 2007, K-Earth had improved its ratings substantially and was once again a Top 10 Los Angeles station. More importantly from an advertising standpoint, the station was attracting a younger demographic. In 2010, K-Earth began adding songs from the late 1980s and early 1990s into its mix from artists such as Janet Jackson, The Bangles, Deniece Williams and The Police. KRTH still plays an occasional pre-1964 song such as "Shout", "Jailhouse Rock", or "Tequila" (about one every other hour).
A slight format change occurred as KRTH added adult contemporary Christmas music during the holiday season from performers such as Mannheim Steamroller, Air Supply, and Barry Manilow. Airing three times an hour, this holiday fare is designed to entice listeners away from adult contemporary KOST-FM, which annually shoots to #1 in the ratings with its all-Christmas music. (In years past, K-Earth played a similar amount of Christmas music, but only from "oldies" artists such as the Beach Boys or the Chipmunks.) At 12:00 PM on Christmas eve, KRTH will switch to an all Christmas music format into 12:00 PM Christmas day.
KRTH has been sold twice in its history and changed hands in a corporate merger an additional time. It was first sold in 1989 to Beasley Broadcasting, and then again in 1994 to Infinity. In 1997, in a corporate merger, CBS Radio (the current owner) acquired the station.
In November 2009, the station reached its first milestone by reaching their first #1 overall in the Arbitron 12+ Ratings. The station had never reached a #1 overall in its 37 years broadcasting as K-Earth.
On August 11, 2011, special jingles commemorated KRTH's 70th anniversary. KRTH is the oldest continuously operated FM station in southern California, as it signed on in 1941.
After Labor Day 2013, (months after the departure of Program Director Jhani Kaye) under PD Rick Thomas, KRTH began to transition out of a portion of 1960's music, due to the fact that the music had appealed more to older audience than was measurable by the ratings system. Additionally, a new generation of classic hits from the 80's were introduced to the mix and ratings began to rise substantially. Also, most early 1970's music, as well as Soul hits from the late 1960's though the mid 1970's, were eliminated.
In June 2014, CBS transferred PD Rick Thomas to New York, with Chris Ebbott replacing Thomas as Program Director.  Ebbott was previously PD at CKFM in Toronto. Also in 2014, Johnny Mann, whose singers have been responsible for KRTH's jingles over the years, died. Additionally, Charlie Van Dyke, who was KRTH's voiceover artist in recent years but has also recently been the image voice for KABC-TV, was replaced as the voiceover with Joe Cipriano, the longtime voice of the Fox Television Network.
A second hybrid channel, KRTH HD-2, was created in 2010, originally featuring songs from the 1955-70 period, with an emphasis on the late 1960's and Motown, which had been removed from the main channel's playlist. The HD2 station was originally branded "K-Earth Classics" and also streamed online. KRTH HD-2 was reported by social media sites and the TuneIn platform to be the highest listener rated station of CBS Radio's O&O oldies stations.
On May 11, 2016, KRTH-HD2 dropped K-Earth Classics and switched to Radio Disney.
KRTH HD-3 airs an all-Beatles format.
An HD Radio, usually already pre-installed in most modern automobiles, is required for HD channel reception. KRTH HD-1 is streaming online, however KRTH HD-2 is no longer streaming. In early 2010 (like other CBS Radio stations), online streams were discontinued outside the United States.
- Brian Beirne "Mr. Rock 'N Roll",
- Robert W. Morgan (Deceased)
- "The Real" Don Steele (Deceased)
- Rich Fields (former announcer on The Price is Right)
- Bob Shannon
- Charlie Tuna (Deceased)
- Roger Christian
- Charlie Van Dyke
- Gary Bryan
- Dave Hull "The Hullabalooer"
- Wolfman Jack (Deceased)
- Sean "Hollywood" Hamilton
- Charlie Van Dyke
- Dan Ingram (One week only)