Philadelphia's newest radio station, signing on this morning, is NOW 97.5, a soft rock station.

The station, which previously played smooth jazz, now features a younger leaning adult contemporary format with a variety of artists ranging from Madonna, Rob Thomas and Kelly Clarkson to Rod Stewart, Elton John and Phil Collins.

Station owner Greater Media on Friday silenced smooth jazz after less than two years. Greater Media had picked it up in November 2006, about three months after Clear Channel dumped the format, which had been heard at 106.1 for 13 years.

"Smooth jazz," a hybrid of light pop and instrumentals that irritates jazz purists, was dogged by low ratings. In the last Arbitron ratings, the station was 23d among all listeners.

Radio analyst Tom Taylor of Radio-Info.com suggested that the Portable People Meter, an electronic device that replaced the paper diaries used to determined ratings, did not help the smooth jazz formats around the country.

Several cities recently lost their smooth jazz station, including New York (now rock), Washington (now Imus and "True Oldies"), Baltimore (rock) and Denver (sports talk).

"The change in methodology is creating some winners and losers, and at least the perception in the radio industry is that smooth jazz won't be one of the winners," Taylor said. "That's because the meter seems to favor stations that have very broad reach or cumulative audience, versus stations that have a smaller audience that gives them more listening (or quarter hours). What the meter's showing generally is that people listen on more occasions than the diary showed, but listened for less time per occasion."

He also believes that the meter may show men listening to the radio more than women. "Arbitron explains that by saying that men are more likely to be employed outside the home,' he said. "Skeptics question that, and wonder if it's because women are less apt to wear the pager-sized device or keep it handy."

Contact staff writer Michael Klein at 215-854-5514 or mklein@phillynews.com. See his recent work at http://go.philly.com/insider.