KNX Los Angeles Turns 99
California Mediumwave Station Celebrates 99 Years
Dr. Adrian M. Peterson
October 13, 2019
The well known powerful mediumwave station KNX in Los Angeles California is heard regularly in season at night throughout the western areas of the United States and Canada, as well as across the Pacific in Hawaii, Japan, the exotic South Pacific Islands, New Zealand and Australia. Station KNX radiates 50 kW on 1070 kHz from a single tower, and it celebrated 99 years back in September (2019). This is their story.
1951 QSL from KNX for reception in New Zealand
© Radio Heritage Foundation, Laurie Boyer Collection
It was on Friday evening September 10, 1920, that wireless experimenter Fred Christian began the broadcast of music records over his amateur station 6ADZ in his home at 5118½ Harold Way in Hollywood California. At the time, Fred Christian owned and operated a shop at 216 West Third Street in nearby downtown Los Angeles under the commercial name, Electric Lighting Supply Company.
In addition to the sale of electrical items, Fred Christian was also selling wireless parts to local experimenters who assembled them into radio receivers. In view of the fact that the radio spectrum in California was almost entirely empty back then, he activated a 5 watt transmitter in his back bedroom in the evenings so that the locals could tune in to his borrowed music records on their home made receivers. This amateur demonstration broadcasting station 6ADZ operated on 1500 kHz at the top end of what initially became the standard mediumwave band.
On December 1 of the following year (1921), the Department of Commerce in Washington DC issued new regulations for licensed radio broadcasting stations that back then permitted the use of just two frequencies. These two allotted mediumwave channels were 360 m (833 kHz) for entertainment programming; and 485 m (619 kHz) for what we might call essential services, market and weather reports.
Along with these new radio regulations, all radio broadcasting stations in the United States were granted new callsigns, and the little music broadcasting station 6ADZ in Hollywood was granted a new sequential callsign KGC. At that stage, the physical location for this primitive broadcasting station was still the Hollywood home of the Christian family.
However soon afterwards, Fred Christian applied for a second radio broadcasting license, this time for installation at his work location at 216 West Third Street in Los Angeles, and he was granted another sequential callsign KNX. However, before the new station went on the air, a new location was chosen, this time in the California Theater also in downtown Los Angeles, for both the studios and the transmitter. The first broadcast from this new KNX, with the tower on top of the building, was presented on Saturday June 10, 1922 on the then authorized 588 kHz.
Now that the new KNX in Los Angeles was on the air, Fred Christian no longer needed the older KGC in Hollywood, so the two year old station was deleted from the Department of Commerce records ten days later on June 20 (1922). According to official government documents, KNX was recognized as a direct follow on from the original KGC, and thus the now well known and the very modern KNX traces its earliest origin back to September 10, 1920, exactly 99 years earlier.
Two months later, the power level at KNX was increased to 100 watts. Give two more years again (Autumn 1924) and the successful KNX was purchased by Guy Earl who was the owner of the Los Angeles Evening Express newspaper and he raised the power level to 500 watts.
1976 QSL from KNX for reception in New Zealand
© Radio Heritage Foundation, Chris Mackerell Collection
Soon after that, KNX was procured by Paul Hoffman who transferred the station to the Studebaker Building in Hollywood, with a frequency move to 890 kHz. Then in 1928, KNX was procured by the Western Broadcasting Company, with a subsequent change of frequency to 1050 kHz and a power increase to 5 kW, and subsequently to 10 kW.
In 1933, the station was moved into a new set of studios at what became its most famous location on Sunset Boulevard in Hollywood with yet another subsequent power increase to the maximum 50 kW. Around that time, there was a power race on in the United States, and several major mediumwave stations applied for the superpower level of 500 kW, with the intent of covering most of the north American continent from a single location.
Station KNX in Hollywood also applied for a license in 1935 to install its own 500 kW superpower transmitter. However soon afterwards, KNX withdrew that request, due no doubt to the fact that a superpower station on the west coast of the United States would waste much of its extensive coverage over the Pacific Ocean, even if they installed an elaborate and very expensive directional antenna system.
Station KNX was purchased by CBS, the Columbia Broadcasting System in 1936, though its ownership is registered today with Entercom, a company that merged with CBS in 2017. In 1938, the KNX transmitter site was moved from the San Fernando Valley to a 12 acre site at the junction of 190th Street and Hawthorne Boulevard at Torrance in the South Bay area of Los Angeles. In March 1941. the frequency for KNX was changed to 1070 kHz where it has been ever since.
During the night of September 14, 1965, vandals felled the single KNX tower at Torrance by cutting a turnbuckle on one of the support cables. The falling tower leap-frogged over the transmitter building without causing any additional damage. The culprits were never apprehended.
The mediumwave programming was immediately switched to their FM transmitter on Mt Wilson
overlooking the Los Angeles basin and then next day the programming was transferred to a 10 kW mediumwave transmitter with a single wire antenna strung between two hastily erected wooden poles back at their Torrance transmitter site. A 494 ft tower was then obtained from the nearby mediumwave station KFAC and it was erected on the same KNX property in Torrance.
Ultimately a full height new tower was installed as the main tower and the KFAC tower became the back up tower for KNX. The original transmitter building was subsequently demolished to make way for a car dealership, and a new and smaller transmitter building was erected closer to the main tower.
KNX recorded in Los Angeles in 2012
© Radio Heritage Foundation, Chris Mackerell Collection
Station KNX was one of the original clear channel stations under the 1928 band plan and it continues to operate under its Class A license with 50 kW on 1070 kHz non directional day and night. For the first half of its history, KNX was a general entertainment station with a host of famous personalities, such as Jack Benny, Bing Crosby, George Burns and Gene Autry.
The presenter of their Morning Show from 1957 to 1965 was Bob Crane who later went on to star in Hogan’s Heroes. However, after Bob’s departure the station’s ratings began to slip. So in the Spring of 1968, they changed their format to become a news station, a format with which they have enjoyed success ever since.
These days KNX broadcasts a hybrid analog/HD digital on 1070 kHz during the day time and analog only at night. They can also be heard round the clock on the HD2 channel of their sister station KRCH FM on 101.1 MHz.
Our thanks to Ray Robinson at shortwave KVOH in Los Angeles for alerting us to the 99th anniversary of the CBS mediumwave station KNX, in Los Angeles.
Dr. Adrian M. Peterson, Indianapolis, Indiana USA
Original article broadcast on AWR "Wavescan"
Sunday October 13, 2019
|99 Years of Mediumwave Station KNX California|
| 1920|| Jan|| Only 4 mediumwave broadcasting stations on the air in the United States|
| 1920|| Apr|| Lee de Forest, California Theater 6XC, daily broadcasting began |
| 1920|| Apr|| 6XD 325 m (920 kHz) began playing Victor Phonograh records|
| 1920|| ||Charles Herrold 6XF, thought to be active experimentally, now KCBS |
| 1920|| Sep 10|| Fred Christian began broadcasts over amateur station 6ADZ
5 watts on 1500 kHz
Demonstration station, people buy parts, construct own receiver
Christian home 5118½ Harold Way, Hollywood, back bedroom
First studio in Christian home
First radio station in the area|
| 1921|| Jun 30|| DoC listing, 6ADZ location W 3rd St LA|
| 1921|| Dec 1|| Dept Commerce, new regulations
Two broadcast categories
Entertainment 360 m (833 kHz) & market & weather 485 m (619 kHz)
Located at Christian home
Still only 5 watts|
| 1921|| Dec 8|| License issued for KGC randomly assigned, Fred Christian
5118½ Harold Way, Hollywood|
| 1922|| May 4|| License issued for Electric Lighting Supply Co on 3rd St
Electric Lighting Supply Co, 216 W Third St, Los Angeles
Randomly assigned KNX|
| 1922|| Jun 10|| New KNX first program from new location California Theater
Downtown LA. 8th & South Main St
Tower on roof
Sat evening 510 m (588 kHz)|
| 1922|| Jun 20|| KGC formally deleted from Dept Commerce records
Dept Commerce recognized KGC-KNX as just the one station|
| 1922|| Aug|| Power increase to 100 watts|
| 1924|| Fall|| KNX purchased by Guy Earl, owner LA Evening Express|
| 192x|| Power increase to 500 w|
| 192x|| KNX transferred to Paul G. Hoffman Studebaker Building, Hollywood
Hollywood Boulevard & Gower St|
| 192x|| Move to 890 kHz|
| 1928|| Early|| KNX procured by Western Broadcast Co|
| 1928|| Nov 11|| FRC reassigned KNX to 1050 kHz|
| 1929|| Jan 3|| Moved to LA|
| 1929|| Power increase to 5 kW|
| 1932|| Power increase to 10 kW|
| 1933|| Studios moved to another part of Hollywood, power increase to 25 kW
| 1934|| Power increase to 50 kW|
| 1935|| Oct 21|| Lodged application for 500 kW
KNX withdrew request|
| 1936|| KNX purchased by CBS, became CBS West Coast Flagship station
New tower erected|
| 1937|| Jan 1|| Joined CBS|
| 1938|| CBS Columbia Square Studios Hollywood dedicated
6121 Sunset Boulevard
Separate line for shortwave feed to KGMB Honolulu |
| 1938|| Apr 30|| Special programming all day, honoring opening CBS Columbia Square
Coast to coast in the United States on CBS
Coast to coast in Canada on CBC
To Europe on shortwave|
| 1938|| Sep|| Began transmitting from new building on 12 acre vacant lot
Moved from San Fernando Valley to Torrance
190th & Hawthorne in Torrance
On edge of 52 acre park, some KNX land added to park|
| 1941|| Mar|| Band reshuffle, KNX given 1070 kHz
| 1965|| Sep 14|| Tower destroyed by vandals, hacksaw cut turnbuckle on support cable.
Vandals never caught
Falling tower jumped over transmitter building, no damage
Off air one day, programming via FM on Mt Wilson
Temporary 10 kW transmitter, low long wire strung between 2 wooden poles |
| 1966|| New 494 ft tower installed, KFAC tower not yet erected
Now in use as emergency tower|
| 1968|| Spring|| Programming turned to all news format|
| 2005|| Aug|| Moved into new studios Miracle Mile, Wilshire Boulevard|
| 2019|| ||First transmitter building demolished for car dealership, tower moved a little east |
Visit the KNX website knx1070.radio.com
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