-By Katy Bachman

The days of listening to the big game on the AM dial may be numbered. As part of a broad strategy to migrate more affiliates to FM, ESPN Radio recently signed an affiliation deal with Greater Media, putting the iconic sports brand on WNUW-FM (a simulcast with sister station WPEN-AM) for the first FM Sports station in Philadelphia.

The station is the 29th FM affiliate ESPN has signed since January—two years ago, ESPN had only 10 FM affiliates. Out of 364 full-time affiliates, 54 stations (15 percent) are on the FM band. “FMs are clearly a better listening experience,” said Traug Keller, senior vp of ESPN Radio. “There’s no doubt Sports and Talk [formats] are going to migrate to FM. You’ll see this trend continue.”

ESPN isn’t the only radio company figuring out how to move talk programming from AM to FM. CBS Radio has launched sports on FM stations in Detroit, Baltimore, Dallas, Washington, D.C., and Boston. Bonneville has moved News/Talk formats to FM in markets such as Washington, Seattle and Phoenix.

The reasons for the trend are striking. There is a much larger and more diverse pool of listeners to the FM band. According to Arbitron, 79 percent of listening is to FM.

Three-quarters of FM listeners never tune to AM. FM listeners are younger (only 37 percent are older than 50 compared to 67 percent on AM), and there are more female listeners. “Now that iPods and digital devices, the Internet, and the prospect of royalty fees have put FM music formats at peril, it has become really attractive to move spoken-word formats to FM,” said Gabe Hobbs, president of Gabe Hobbs Media.

All that translates into a better revenue proposition for ESPN. While network radio revenue is down 11 percent, ESPN is up more than 8 percent, according to John Fitzgerald, vp of sales for ESPN Radio, who declined to talk actual dollars.

Moving to FM isn’t an all-or-nothing proposition. There are still a number of highly desirable, big blowtorch AM signals that are hard to beat—such as CBS Radio’s WFAN-AM in New York.

With a few exceptions, the industry is struggling with what to do with most AM properties. Noted Hobbs: “We’ll have to find other uses for AM or reinvent the band. Some of the weaker AM signals will go dark.”