Section C, story 34 min read
Chicago’s call letters are small pieces of history. Many of the city’s best-known stations still use names chosen a century ago, and those names often explain who started them and why. This short history follows three stations whose own archives tell their story: WGN, WLS and WTTW. It sticks to what those archives say, which is why some famous names are missing; telling every station’s story properly would take a book.
WGN: the World’s Greatest Newspaper
WGN Radio’s own archive gives the station’s origins in some detail. The station that became WGN started as WDAP, founded on May 19, 1922 by Thorne Donnelley and Elliott Jenkins. The Chicago Tribune first used the call letters WGN on a different station: on the night of March 29, 1924, the Tribune, having obtained the letters, put them on the air from a station at the Zenith Edgewater Beach Hotel. For the first time, the archive says, Chicago listeners heard the call sign representing the World’s Greatest Newspaper, the Tribune’s motto.
The arrangement did not last long. A little more than two months later the Tribune ended its association with the hotel station and partnered with WDAP instead, and on June 1, 1924, WDAP became WGN. The archive notes that elements of several stations were combined over the years into the 50,000-watt WGN Radio 720 of today. The FCC still lists WGN at 720 kHz, licensed to Tribune Media Company, and WGN-TV on virtual channel 9.
WLS: the World’s Largest Store
In the same year, 1924, a very different company started a Chicago station. According to ABC7 Chicago, which today broadcasts as WLS-TV, the new station began under the ownership of Sears. It was assigned the call letters WBBX, but Sears first broadcast under the letters WES, for World’s Economy Store, and then under WLS, for World’s Largest Store.
Sears sold the radio station in 1928, ABC7 notes, but it continues to operate as WLS to this day, as does ABC7 Chicago as WLS-TV. The FCC lists WLS radio on 890 AM and WLS-TV on virtual channel 7. The call letters of a department store slogan have outlived the original owner’s connection by nearly a century.
| Call sign | What it stood for | First used | Source |
|---|---|---|---|
| WGN | World’s Greatest Newspaper (Chicago Tribune) | March 29, 1924 | WGN Radio archive |
| WLS | World’s Largest Store (Sears) | 1924 | ABC7 Chicago |
| WES | World’s Economy Store (Sears) | 1924, before WLS | ABC7 Chicago |
| WTTW | Window to the World | 1955 | WTTW history page |
WTTW: Window to the World
Television came later. WTTW’s history page says the station was founded in 1955 by Inland Steel chairman Edward Ryerson and other civic leaders to bring educational television to the city. Its first program, Report to the Teachers, premiered on September 6, 1955, one of what grew to 40 regularly scheduled programs a week, many broadcast from a temporary studio in the Bankers Building downtown.
By its first anniversary, the station says, it had produced the first remote broadcast from Orchestra Hall, the first language course, the first series on income tax preparation and, with Chicago’s Board of Education, college courses for credit through its TV College series. WTTW moved in August 1965 to its current home at 5400 North St. Louis Avenue and in the fall of 1970 became a charter member of the new Public Broadcasting Service.
The station’s history also claims a film-world first. In the following decade it launched television’s first movie review series, Opening Soon at a Theater Near You, later retitled Sneak Previews, featuring the critics Roger Ebert and Gene Siskel. In the 1980s came Chicago Tonight, which the station says is still on the air, and later Geoffrey Baer’s tours beginning with Chicago by Boat. In 2003, the page notes, WTTW became a fully digital broadcaster and launched WTTW Prime on channel 11.2.
From AM towers to digital TV
The technology has changed completely since 1924. The first stations were AM radio; today Chicago’s TV stations broadcast digitally, often sharing one transmitter between two licensed stations, and the industry is rolling out a new standard called ATSC 3.0, marketed as NextGen TV. Even the radio dial has moved: in 2026 the sports station The Score, long an AM station, added a full FM simulcast on 104.3. What has stayed the same is the call letters, which is why a newspaper motto and a department store slogan still identify two of the city’s biggest broadcasters.
Tip: Curious about a call sign’s origin? Start with the station’s own about or history page, where many stations tell their story. Origins passed around online are not always accurate.
Where these stations are today
- WGN Radio: 720 AM. WGN-TV: channel 9.
- WLS radio: 890 AM. WLS-TV, ABC7 Chicago: channel 7.
- WTTW: channel 11, Chicago’s PBS station, with WFMT on 98.7 FM under the same licensee.
For the full present-day line-ups, see Chicago TV Channels: The Local Stations You Can Watch With an Antenna and Chicago Radio Stations by Frequency: FM and AM From Bottom to Top. For more on WTTW and Chicago’s other public stations, see Public Radio and TV in Chicago: WBEZ, WTTW, WFMT and the College Stations, and for the new broadcast standard, NextGen TV in Chicago: What ATSC 3.0 Means for Antenna Viewers.