For 24 hours straight, radio station 98 Rock played nothing but Led Zeppelin's Stairway to Heaven. That 1990 promotional stunt by the station's new owners garnered national media coverage. But the owners had to take a different approach when they started sister station Thunder 105 in New Port Richey this year. They didn't promote it at all. They didn't even have disc jockeys. That's because after finally deciding on the perfect name for a classic rock 'n' roll radio station _ Thunder _ the new owners feared Vince Naimoli was about to name his Tampa Bay baseball team the same thing. "They had mentioned Thunder as one of the possible names and if (the team) was named that we didn't want to seem like copycats," said Dan DiLoreto, the radio station's general manager. "We'd seem like a bunch of dullards." So on March 9, the station started playing album sides, one after the other, with no DJs and no advertising. That same day Naimoli announced he had been awarded a major-league baseball franchise and that it would be called the Tampa Bay Devil Rays. "We got absolutely no press that day," DiLoreto said. "But the good news was they didn't call the team Thunder." In less than a year the station has developed a respectable following of classic rockers devoted to the Who, the Doors, Janis Joplin and Cream. Its target audience is men ages 30 to 40. The real challenge, however, comes in convincing area advertisers that in this county dominated by retirees, there still is a sizable audience of these classic rockers out there that they need to reach. Thunder 105 (WTBT-FM 105.5) is owned by Cincinnati-based Citicasters Co., which also owns 98 Rock WXTB-FM, WTSP-Ch. 10 in Tampa and 15 other radio stations across the country. It started Thunder after acquiring big band station WGUL-FM, which is now at 96.1 FM. Transmitting from a 280-foot tower in Port Richey, Thunder reaches Pasco County and northern Pinellas and Hillsborough counties. Eventually it will broadcast from a new, 1,400-foot tower just completed in the Anclote area of southwest Pasco. Although 98 Rock will broadcast from there within weeks, Thunder must first get FCC approval, which could take more than a year. Whatever the size of the market, DiLoreto thinks Thunder is the only station in the area that offers the best of classic rock 'n' roll _ and only classic rock 'n' roll. "We're reaching the baby boomers whose lifestyles have changed, but their passion for their music hasn't," DiLoreto said. "They don't identify as much with today's new rock but more with the music they were listening to when they went through their rite of passage." What's Jimi Hendrix doing in Pasco? First of all, most Pasco County residents aren't listening to rock 'n' roll, even if it is classic. DiLoreto agreed, but said when you add the listeners in northern Pinellas and Hillsborough counties to those in Pasco, there's a serious shift in the age demographics. While the median age in Pasco County is 46, the median age in the five northernmost zip codes in Pinellas County is 42. And in the seven zip codes in the northwest corner of Hillsborough County, the median age is 34. "You put all those zip codes together, and all of the sudden your population model starts to look very normal," he said. But even when potential advertisers realize that Thunder's music does have a market of listeners in north Tampa Bay, they're not so sure they need to reach them. "Everybody in business in Pasco County really does cater to that older population," DiLoreto said. "You really have to educate retailers to the fact that there are a lot of people here who aren't over 55." Tom Castriota, owner of Castriota Chevrolet-Geo in Hudson, was one of those retailers. "I didn't know this market was here," he said, referring to car buyers age 25 to 45. "We're selling more Cavaliers than we did last year, and that's a car that people 25 to their mid-30s buy." Of course Castriota still spends more money on reaching the older audiences who buy the Caprices and Luminas, but Thunder gets a fair share. The dealership spends a third of its radio advertising dollars with Thunder and one-third each with WGUL and WLVU. Thunder's programing schedule calls for nine advertisements per hour. It has been selling close to six per hour but had its first sold-out week in early November. About half of Thunder's advertising clients are national and half are local. Of the local advertisers, most are in Pasco and Pinellas. Of course, Pasco retailers have always had the option of advertising on St. Petersburg and Tampa stations, which reach Pasco as well as the rest of Tampa Bay. And some do. But with a smaller market, Thunder's rates are lower. Also, Pasco advertisers don't have to pay to reach people in Sarasota, south Tampa or Plant City. New button on the dial Citicasters has not yet filed for the FCC approval it would need to broadcast Thunder from the new tower. One reason is a Christian station in Sarasota with the same 105.5 frequency has to get approval first to switch its frequency. It could be as early this spring or as late as spring 1997 when the station wil start broadcasting from the taller tower and reach a larger audience. With a listening market that DiLoreto said is half as big as most of its competitors', recent Arbitron ratings show Thunder ranks ninth in the category of listeners age 25 to 54. It has a 4.6 share of that category, while leader 98 Rock has a 9.8 share. WQYK-FM 99.5 comes in second with a 6.6 share and the Point 102.5 is third with a 6.5 share. For that reason, competing stations probably aren't too concerned with Thunder _ yet. "Neither the Coast nor the Point have felt the economic impact," DiLoreto said, referring to Coast 107.3 and the Point 102.5. "But they probably look at those numbers and think, "What's going to happen to us when they get up on that tower?'" Drew Rashbaum, general manager of the Point, said Thunder certainly concerns him, but he isn't losing any advertisers to it. "My guess is they probably are getting some (102.5) listeners in northern Pinellas and Pasco," he said. Thunder is filling a niche by serving those people who want rock 'n' roll and nothing else, he said. He added, however, that Thunder has limited its music library with that theme and that it might grow old. The Point plays classic rock as well as new rock releases. Thunder's other leading competitor is Coast 107.3, which plays all '70s music. In some ways Thunder competes with its own sister station, 98 Rock, because they both want to attract similar-aged listeners of rock 'n' roll. But 98 Rock's music has a little bit of a harder edge. For example, the Beatles' "Yesterday" would work on Thunder but probably not on 98 Rock. "98 Rock is building Thunder's library of the future," DiLoreto said. "Fifteen years from now Thunder will play Pearl Jam because that will be the classic rock."