|City of license||Fresno, California|
|Broadcast area||Fresno, California|
|Slogan||"News Talk Radio"|
|First air date||1922|
|Power||50,000 watts (unlimited)|
KMJ first began broadcasting in March 1922; it was originally owned by the San Joaquin Light and Power Corporation, and was later acquired by the McClatchy Newspaper Company in 1925. It is the 38th oldest licensed, and continuously operated radio station in the United States.
When the station first began broadcasting, it was licensed as an "E & M" station, and shared those frequencies with every other E & M station in existence at the time.
KMJ operated on a number of other frequencies between 1925 and 1932; some of the frequencies used included 820 and 1350 kHz.
McClatchy was intent on improving the signal, and competed with KTAB in Oakland for a new frequency (580 kHz), which was being made available by the newly created FCC.
Eventually, they were awarded the new channel, and KMJ moved to 580 kHz in 1932, operating with 1 kW non-directional from a building rooftop in Downtown Fresno.
In 1936, a new 5,000-watt non-directional transmitter site was constructed, which utilized a 5/8 wave antenna, and was located 5 miles east of Fresno, at the northeast corner of the Kings Canyon Road and Fowler Avenue intersection.
Until 1936 and the arrival of KARM, it was the only radio station in Fresno.
The station was an affiliate of the Don Lee Network, and also carried CBS network broadcasts until 1936, when they collaborated with NBC; they remained a NBC affiliate until NBC ceased hourly newscasts in the 1990's. They were then associated with ABC, before rejoining CBS when Westinghouse Electric Corporation (later be renamed CBS Corp.), acquired the station from American Radio Systems in 1998.
Modern studios were constructed as an addition to the Fresno Bee Building on Van Ness Avenue; The studios were subsequently used by Valley Public Radio, and later McClatchy donated the entire building to the Fresno Metropolitan Museum. The addition was demolished in 2007 as part of a renovation of the main building.
In 1941, Hammer Field (which later became Fresno Air Terminal) was constructed, as a training base for the Army Air Corps. The KMJ tower was directly in line with the runway, and the Army wanted the site relocated. They ended up moving the site some 16 miles west of Fresno, to the intersection of Madera and North Avenues (south of Kerman). The transmitter building was moved to the Kerman site, and the existing tower was unstacked and moved as well, however it was only 660 feet in height. The remaining 330 feet were stored on the site, with the intention of creating a directional array; World War II interrupted the project, and it never resumed. The extra portion was eventually moved to Sacramento, and used in the construction of the KFBK transmitter site in 1945.
From 1925 until 1987, KMJ was owned by McClatchy Company, who also owned KFBK in Sacramento, KBEE in Modesto, KERN in Bakersfield, and KKOH in Reno. McClatchy Newspapers owned three daily newspapers in Fresno, Sacramento, and Modesto. In 1953, McClatchy signed on KMJ-TV on channel 24. The television station would be sold off in 1981 to become KSEE.
In 2003 Jaz McKay was added to the line up on the night shift, replacing Bill Manders after his contract was not renewed. Manders subsequently worked at KKOH Reno, Nv. A year and a half after that, Inga Barks was brought in at the request of Sean Hannity to do nights, and Jaz McKay was cancelled and moved on to KNZR in Bakerafield.
In March 2009, Peak Broadcasting replaced the KFJK Jack FM format on 105.9 FM, with KMJ-FM NewsTalk radio; it is a partial simulcast of KMJ AM.
In the fall of 2012, Premiere Radio Networks exercised a termination clause and ended its relationship with both the AM and FM KMJ stations. As of January 1, 2013, all Premiere-controlled syndicated shows were moved to Clear Channel (Premiere Radio Networks' parent company) controlled stations in the greater Fresno area. From 6 AM until 6 PM, Monday through Friday, KMJ AM broadcasts all live and local talk shows (Farm Report/Don York 5-6 AM, Morning News 6-9 AM, Jennifer Lipp & John Broeske 9-11 AM, Ray Appleton 11 AM-2 PM, and Chris Daniel 2 PM-6 PM. The Lipp/Broeske and Daniel programs are simulcast on 105.9 FM, aka the FM KMJ.
Nationally Syndicated host Mark Levin rejoined the KMJ schedule, filling the 6-9pm time slot, on May 24, 2013.
On August 30, 2013, a deal was announced in which Townsquare Media would purchase Peak Broadcasting, and then immediately swap Peak's Fresno stations, including KMJ, to Cumulus Media in exchange for Cumulus' stations in Dubuque, Iowa and Poughkeepsie, New York. The deal is part of Cumulus' acquisition of Dial Global; Peak, Townsquare, and Dial Global are all controlled by Oaktree Capital Management. The sale to Cumulus was completed on November 14, 2013.
In September of 2013, a Special Temporary Authority was granted by the FCC that would authorize KMJ to use the auxiliary site at 5,000 watts while one of its directional antennas undergoes repairs. 
KMJ uses a 50,000 watt transmitter. It has a directional antenna consisting of 4 mast radiators situated at 36-39-37.2 N 119-20-52.8 W, 36-39-29.2 N 119-20-52.8 W, 36-39-27.9 N 119-20-48.3 W, 36-39-36.5 N 119-20-47.1 W; each of the towers is 256.1 metres (840 ft) tall. On a clear night, signals can be picked up as far south as Santa Clarita, and as far north as San Francisco; it can widely be heard in Hawaii, Australia and Japan at night. 
Additionally the 50,000 watt site develops an effective radiated power, of 250,000 watts at a bearing of 270 degrees true. This and the extremely good ground conductivity of the San Joaquin Valley, allow KMJ to produce a signal strength of 50-100 mv/m over the city of Fresno, which is located at a distance of 26 miles (42 km) west of the 50,000 watt transmitter site.
The former main transmitter site at Kerman remains licensed as an auxiliary transmitter site.
- "Official: Cumulus Buys Dial Global, Spins Some Stations To Townsquare; Peak Stations Sold To Townsquare, Fresno Spun To Cumulus". All Access. August 30, 2013. Retrieved August 30, 2013.
- "Cumulus Makes Dial Global And Townsquare Deals Official". RadioInsight. August 30, 2013. Retrieved August 30, 2013.
- "Cumulus-Townsquare-Peak Deal Closes". All Access. November 15, 2013. Retrieved November 16, 2013.
- KMJ Website
- Query the FCC's AM station database for KMJ
- Radio-Locator Information on KMJ
- Query Nielsen Audio's AM station database for KMJ