The Birth of Top 40
KOWH Omaha
In 1949, Todd Storz purchased a daytime station in Omaha, Nebraska. At the time, block programs and network entertainment shows were the norm for successful radio and music was a fill or part of a variety show.The use of recorded music was severely restricted by the American Federation of Musicians.

The background is sometimes fuzzy, with different story lines, but the fact is clear that KOWH was the first station to base its programming exclusively on the top hits of the moment, with no other programming breaking up the constant rotation of the same few dozen songs.

In 1951, the leader was WOW, followed by KFAB. This ad from the Broadcasting Yearbook from the edition prior to the debut of KOWH as a Top 40 station shows how the market looked "before Top 40."
... and After.

Here is an ad from the next year's edition of the Yearbook with KOWH taking the crown for most listening. Not only was this an amazing feat, it is all the more interesting because KOWH only operated from sunrise to sunset.
And even later...

The ratings continued to hold for another year. This is from the 1954 Broadcasting Yearbook edition.
Some say that Storz commissioned a study at a local university, others say that he saw an already finished study. But the study, whoever paid for it, said that people, at the dawn of the television era, listened to the radio in their majority to hear music.

Storz' own anecdotal experience showed that people liked to hear the same "big songs" over and over. One version of that experience has him observing juke box play and noting that the same few songs got most of the play.

Click to read the Television Magazine article about Storz and his stations
May, 1957
Richard Fatherly, who passed in 2011, worked with Todd Storz.  He later produced several narratives about the Storz stations. In correspondence, Mr. Fatherly sent me several documents to clarify points I missed or was wrong on. Read them:

Click: Richard Fatherly's documents.

The audio segments are streamable by clicking any of these:

Click: The Todd Storz Revolution - Radio's Happiest Broadcasters #1

Click: The Todd Storz Revolution - Radio's Happiest Broadcasters #2

Click: The Todd Storz Revolution - Radio's Happiest Broadcasters #3

Click: The Todd Storz Revolution - Radio's Happiest Broadcasters #4

Click: The 1958 DJ Convention

Click: The Radio Revolution

To play:
Intenet Explorer: make sure that your system is set to play m3u files in your preferred audio player (usually Windows Media Player) via Control Panel -> Default Programs -> m3u and select your player if not set already.
Firefox: Tools -> Options -> Applications -> m3u and make sure your preferred audio player is selected.
So, some moment in about August of 1951 KOWH became the first all current hits station.

Among the early Top 40 stations was KLIF in Dallas, where Gordon McLendon launched his own broadcast empire. A fine tribute site is located at:   
Rather than narrate the much discussed creative process behind KOWH, I thought it would be more interesting to show what happened after the format made it through its first ratings book. Here's one of the early ads... from February, 1953 just a month after the first full year of ratings was released.
KOWH Advertisements
A series of similarly themed ads followed.  Here is a series from 1952 to 1955. Click on any of them to see a larger version. There are "hidden" mouse-over forward and back arrows on the right and left that are activated by mousing over them.

By 1954, WTIX in New Orleans and WHB in Kansas City had been added but the theme was the same.
There are many more ads and they later feature additional stations like WQAM and WDGY and KOMA that were added to the group. To demonstrate the search feature of this website, here is a link to a search that will give you several hundred KOWH references. Click on the picture of Mr. Storz to see them.
Or, if you want to search for the other stations, click the magnifying glass below to go to the Broadcasting Magazine search page and enter search terms like "Storz" or "WQAM" to read further about what started the rebirth of radio. I'd suggest limiting the search to the 50's or even to 1951, 1952, 1953 and 1954 to reduce the quantity of links you will generate. You may also want to searh other magazines on the site such as Sponsor, Radio Daily, and USA Radio