KLZ TheSource logo.png
Broadcast areaDenver-Boulder-Longmont and Northern Colorado
Frequency560 kHz (HD Radio)
Branding560 KLZ The Source
FormatConservative talk
AffiliationsUSA Radio News
OwnerCrawford Broadcasting
First air date
March 10, 1922 (also amateur station licenses as 9JE 1920-1921 and 9ZAF 1921-1922)
Call sign meaning
None (random reissue)[1]
Technical information
Facility ID35088
ClassAM: B
Power5,000 watts (unlimited)
ERP99 watts (FM translator)
Transmitter coordinates
39°50′36″N 104°57′14″W / 39.84333°N 104.95389°W / 39.84333; -104.95389
Translator(s)100.7 MHz K264BO (Denver)
WebcastListen Live

KLZ (560 AM) is a commercial radio station licensed to Denver, Colorado and owned by Crawford Broadcasting. KLZ received its first broadcasting license on March 10, 1922. It is the oldest broadcasting station in the state of Colorado, and one of the oldest in the United States.[2]

The station's 5,000-watt signal covers much of the population center of Colorado, from Fort Collins to Colorado Springs and Pueblo.[3] The station also transmits an HD digital sub-channel.[4][5] In addition, listeners in Denver can hear KLZ programming on the FM dial, on translator K264BO 100.7 MHz.[6]

KLZ airs a talk radio format, branded as "KLZ The Source", featuring several nationally syndicated talk hosts as well as local shows, much of it paid brokered programming. Topics include money and investing, real estate and health.

Station history

Experimental Years

KLZ was first licensed as a broadcasting station on March 10, 1922 to the Reynolds Radio Company in Denver, Colorado. However, the company's president, Dr. William D. "Doc" Reynolds Jr., had been making earlier experimental broadcasts, and the station has traditionally traced its founding to 1919[7][8] or 1920.[9]

In September 1915, Reynolds, then living in Minneapolis, Minnesota, was issued his first license, for an amateur radio station with the call sign 9WH.[10] This initial station employed a spark transmitter that could only transmit the dots-and-dashes of Morse code. With the entrance of the United States into World War I in April 1917, all civilian radio stations were ordered to cease operations for the duration of the conflict.

In late 1919 the amateur radio ban was ended and Reynolds, who had subsequently moved to Colorado Springs, relicensed his amateur station, which was now issued the call sign of 9JE.[11] During the war, vacuum tube radio transmitters had been developed that made audio transmissions practical. Reynolds began work with the U.S. Forestry Service to evaluate the practicality of using radiotelephones to aid department communication.[12] He also took advantage of the equipment provided by the Forestry service to experiment with entertainment broadcasts, and one of his first radiotelephone tests, in May 1920, provided musical selections for a dance held by students at a local high school.[13]

The studio, transmitter and antenna for Special Amateur station 9ZAF and broadcasting station KLZ were originally located at William Reynold's home (1922)
The studio, transmitter and antenna for Special Amateur station 9ZAF and broadcasting station KLZ were originally located at William Reynold's home (1922)

In late October 1920, a newspaper account stated that Reynolds was broadcasting nightly concerts. This report also noted he had decided to suspend his dental practice in order to devote full-time attention to radio, and had founded the Reynolds Radio Specialty Company, which was located at his home on South Prospect Street.[14] The following February another newspaper article stated that he had been broadcasting regular Sunday evening concerts, and it was also announced that Reynolds was making plans to move his family and his company to Denver.[15] (Reflecting this change, the Commerce Department's June 1921 amateur station call book entry for 9JE lists its new location as Denver, operated by the Reynolds Radio Specialty Co.)[16]

After moving to Denver, Reynolds joined with other radio enthusiasts in making a number of "mobile" demonstrations, where radio-receiver equipped automobiles picked up special programs. He participated in the May 19, 1921 broadcast of the opera Martha from the Denver Municipal Auditorium.[17] In the summer of 1921, Reynolds was issued a "Special Amateur" license, with the call sign 9ZAF.[18] This allowed transmissions on 370 meters (811 kHz), a wavelength with less interference than 9JE had encountered on the congested standard amateur wavelength of 200 meters (1500 kHz). In addition to experimental broadcasts, 9ZAF acted as a "relay station" for coast-to-coast messages passing through a cooperative network of Amateur Radio Relay League stations.[19] In October, it was announced that 9ZAF's equipment had been upgraded, and, in addition to Sunday evening concerts from 8:00 to 9:30 p.m., the station was broadcasting daily weather forecasts twice a day, at 8:30 a.m. and 9:00 p.m.[20] In early 1922, the Rocky Mountain News announced it was providing news bulletins as a supplement to the nightly station concerts.[21] The paper also started promoting 9ZAF, referring to the station as the "News-Times-Reynolds Broadcasting station".

The Start of KLZ

Dr. William D. Reynolds broadcasting over KLZ (1922)[22]
Dr. William D. Reynolds broadcasting over KLZ (1922)[22]

Initially, there were no formal restrictions about which radio station license categories could make broadcasts intended for the general public. However, effective December 1, 1921, the Department of Commerce, which regulated U.S. radio at this time, adopted a regulation that stations making general broadcasts now had to hold a Limited Commercial license.[23] To comply with this new standard, the Reynolds Radio Company applied for the appropriate license, and on March 10, 1922 a broadcasting station authorization — the first in the state of Colorado — with the randomly assigned call letters of KLZ was issued to the company. KLZ was given permission to use both of the broadcasting wavelengths established by the new regulations: 360 meters (833 kHz) for "entertainment" broadcasts, and 485 meters (619 kHz) for "market and weather" reports.[24] (Reynolds' amateur radio transmissions, although using the same equipment as KLZ, continued as 9ZAF on 370 meters). In late March, the Rocky Mountain News reported the station's schedule as "KLZ (ex-9ZAF), News-Times-Reynolds service begins broadcasting news, market reports, and concerts and a good-night story for the children at 7:30 p.m. Sermons and music Sundays from 8:00 to 9:30 p.m. at 360 meters" in addition to "Market reports and financial news daily at 12:30 noon,[sic] except Sundays, at 485 meters".[25]

KLZ was initially located at Reynolds' home at 1124 South University Boulevard in Denver. Two 80 foot (25 meter) towers had been erected, one in front of the house and the other behind, to support a large "flat-top" transmitting antenna and counterpoise. A room in the house was set aside as a studio and also housed the station's transmitter. Initially Reynolds — who played saxophone and violin — and his wife Naomi — who played piano — provided much of the entertainment, and they were later joined by their young son.[26] KLZ's studios later moved to the Shirley-Savoy Hotel (Savoy opened in 1904; Shirley opened in 1903; joined in 1919; razed in 1970),[27] with the station antenna constructed atop the building.[28][29]

In 1927, the Federal Radio Commission was formed to regulate radio stations in the United States. It embarked on a major restructuring of the broadcast band, and, on November 11, 1928, under the provisions of General Order 40, KLZ was assigned to operate on 560 kHz, which it has continued to use ever since. This assignment specified a transmitting power of 1,000 watts, then the maximum permitted for stations operating on a "regional" frequency. KLZ was later able to take advantage of the adoption of higher limits, eventually increasing its power to 5,000 watts, its current rating.

Dr. Reynolds died in November 1931, and KLZ signed off for three hours in his memory.[30] In 2014, he was inducted into the Broadcast Pioneers of Colorado's "Broadcast Pioneers Hall of Fame".[31]

KLZ timelines

Later history



  1. ^ "Broadcast Station Calls With a Past" by William Fenwick, Radio Broadcast, July 1928, page 150. The KLZ call had previously been assigned to a marine radio station aboard the Speedwell, which sank on September 29, 1920 in the Gulf of Mexico during a hurricane.
  2. ^ "Oldest Broadcasting Stations in the United States" by Thomas H. White (earlyradiohistory.us)
  3. ^ "Predicted Coverage Area for KLZ 560 AM" (Radio-Locator.com)
  4. ^ "HD Radio" (560thesource.com)
  5. ^ "HD Radio guide: Denver" (hdradio.com)
  6. ^ "Predicted Coverage Area for K264BO 100.7 FM"
  7. ^ "Radio stations 40 or more years old in 1962" (KLZ entry), Broadcasting, May 14, 1962, page 124.
  8. ^ "1922--year radio's population soared" Broadcasting, May 14, 1962, page 88.
  9. ^ "KLZ Denver" Variety Radio Directory (1937-1938 edition), page 413. Establishment date for KLZ is listed as June 1920.
  10. ^ "Amateur Radio Stations Licensed During the Month of September, 1915", The Electrical Experimenter, February 1916, page 567. The "9" in 9WH's call sign indicated that the station was located in the 9th Radio Inspection district.
  11. ^ "Ninth District—Alphabetically by owners of stations", Amateur Radio Stations of the United States (June 30, 1920 edition), page 103.
  12. ^ "Reynolds Prepares to Send Messages by Wireless Phone", Colorado Springs Gazette, May 13, 1920, page 10.
  13. ^ "Dance Music by Wireless Transmitted by Reynolds", Colorado Springs Gazette, May 14, 1920, page 8.
  14. ^ "Reynolds Will Devote Time to Inventions and Wireless", Colorado Springs Gazette, October 25, 1920, page 8.
  15. ^ "Radio Specialty Company To Open Plant In Denver", Colorado Springs Gazette, February 23, 1921, page 10.
  16. ^ "Ninth District—Alphabetically by call signals", Amateur Radio Stations of the United States (June 30, 1921 edition), page 191.
  17. ^ "Amateurs Pick Up Denver Radio Music", Rocky Mountain News, May 20, 1921, page 12.
  18. ^ "New Stations: Special Land Stations", Radio Service Bulletin, August 1, 1921, page 3. The "Z" in 9ZAF's call sign indicated that the station held a Special Amateur license.
  19. ^ "Amateur Radio Stations: 9ZAF", QST, January 1923, pages 61-62.
  20. ^ "Wireless Telephone Here to Talk on 1,000 Mile Radius", Rocky Mountain News, October 17, 1921, page 5.
  21. ^ "News Will Send Bulletins Every Night by Wireless", Rocky Mountain News, January 7, 1922, page 9.
  22. ^ "How Denver's Little Store Became Big", The Radio Dealer, January 1923, page 29.
  23. ^ "Amendments to Regulations", Radio Service Bulletin, January 3, 1922, page 10.
  24. ^ Limited Commercial license, serial #316, issued on March 10, 1922 for three months.
  25. ^ "Daily Radio Program", Rocky Mountain News, March 28, 1922, page 5.
  26. ^ "KLZ is a Real Radio in the Home" by Vera Brady Shipman, Radio in the Home magazine, February 1925, pages 29-30.
  27. ^ "Savoy and Shirley Hotels, Denver". CONTENTdm. Denver Public Library.
  28. ^ "Antique Broadcast QSL Card - denver, Colorado - KLZ". hamgallery.com. Retrieved 3 August 2022.
  29. ^ Kreck, Dick. "Radio days recalled". The Denver Post. Retrieved 3 August 2022.
  30. ^ "Radio Station KLZ Denver", Pikes Peak Radio & Electronics Museum (pikespeakradiomuseum.com)
  31. ^ "Broadcast Pioneers Hall of Fame: William 'Doc' Reynolds" (broadcastprofessionals.org)
  32. ^ a b FCC History Cards for original KLZ-FM (covering 1947-1955)
  33. ^ Roberts, Michael (19 Mar 2007). "Games Over". Denver Westword. Retrieved 4 July 2012.
  34. ^ "Six stations being sold for nearly $15 million." Broadcasting - Telecasting, March 8, 1954, pp. 27-28.