Most evenings after dinner, Bjorn Fransson retires to a walk-in closet to fiddle with his powerful Japanese-made radio, hunting through a cacophony of distant voices speaking languages he can't understand.

"It is like collecting stamps or birds," says the 59-year-old Swedish schoolteacher, who lives on the blustery island of Gotland in the Baltic Sea. "We all dream of finding something no one else has."

Earlier this month, while tuning into an AM frequency usually clogged by country music from Prague, he picked up an unfamiliar broadcast in Arabic. He couldn't fathom what was being said but "understood this must be something new."

He made a recording and announced his find on the Internet. Three weeks later, Mr. Fransson is wondering whether his 300 yards of wires and antennas lassoed more than just a new radio station: Did it actually ensnare a covert -- and somewhat clumsy -- American operation aimed at Iraq?

That is certainly the view of many fellow radio buffs, who, having tuned into the enigmatic Arabic station themselves, are now abuzz with speculation that Mr. Fransson stumbled onto an American plot to rattle Saddam Hussein and foment dissent among his most loyal supporters. Some say they've even detected secret messages to U.S. operatives embedded in the station's astrological forecasts.

"I'd be prepared to wager quite a few Iraqi dinars . . . on this station having been invented in a room somewhere in Washington," says Andy Sennitt, a British radio enthusiast who, back in 1974, was the first to find an elusive outfit called Voice of Iraqi Kurdistan. He has a day job with Radio Netherlands.

Nick Grace, the Washington editor of clandestineradio.com, a Web site that tracks illicit radio stations from Iraq to Indonesia, says he's so convinced of a secret American link to Mr. Fransson's find that "I'd bet my whole house on it. . . . This has all the hallmarks of a classic CIA operation." The Central Intelligence Agency declined to comment.

As for Mr. Fransson, who has been hunting exotic radio signals for more than four decades, he's relishing all the excitement. Over the years, he has monitored and received acknowledgement cards from more than 2,000 stations in 216 countries, but this, he says, is the first time he has bagged a possible spy venture.

He has written up his exploit for the magazine of the Swedish radio federation, given interviews on Sweden's state radio and regaled the few people on Gotland island who share his nocturnal passion for unintelligible babble. He has even become a minor celebrity outside Sweden, at least among radio fans, who are known as DX-ers, a name that derives from the Morse-code abbreviation for long distance.

The last time Mr. Fransson stirred any cloak-and-dagger buzz, he says, was 20 years ago when Swedish-security-service agents checked to make sure he wasn't using all the wires entwined around his trees to transmit illegal broadcasts.

When he first picked up the new signal on Feb. 3, the Swede was puzzled by its unusual strength and the constant repetition of words that, to his ears, sounded like "radio secret." It was, he says, "very mysterious." Shortly afterward, though, a Finnish enthusiast tuned in to the same frequency and reported on the Web that the station's name sounded more like "Radio Tigris."

Mr. Fransson turned for help to some Arabic-speaking students in his math class. He played them a cassette tape of the broadcast. "They got quite excited," he says. They told him that the station's name was in fact "Radio Tikrit" and that Tikrit is Mr. Hussein's hometown.

The Iraqi government has no such station, though it does have a Mother of Battles Radio. The Iraqi National Congress, or INC, an umbrella opposition group, says it has nothing to do with Radio Tikrit.

Each evening since the start of the month, a male and female announcer have chanted the same opening jingle: "For all of Iraq and for all Iraqis, this is Radio Tikrit."

As news of Radio Tikrit's discovery spread, Arab radio amateurs tuned in and questioned whether the announcers who claimed to speak "for all of Iraq" were actually Iraqi. Some said their accents sounded more Lebanese. The choice of frequency -- 1584 kHz -- also aroused curiosity: an Iraqi faction long backed by the CIA, Iraqi National Accord, broadcasts on nearby frequencies from a U.S. transmitter in Kuwait.

Tarek Zaidan, an Egyptian DX-er, added another piece to the puzzle. Radio Tikrit's male announcer, he said, sounds remarkably similar to an announcer on Radio Information, an overtly American-run station beamed into Iraq from "Commando Solo" planes flown by the 193rd Special Operations Wing. Mr. Zaidan said this suggests Radio Tikrit was perhaps recorded in studios also used by the Pentagon for some of its own burgeoning radio ventures. These, in preparation for a potential war, include broadcasts from a ground station in northern Iraq and a proposal to set up a clandestine transmitter in Jordan. A spokesman said that as a matter of policy, the Pentagon wouldn't comment.

By mid-February, news of Radio Tikrit had reached an area in the north of Iraq where opponents of Mr. Hussein were gathering for a planned big meeting. Zaab Sethna, a London-based adviser to the INC, had made the journey and, after a tip-off about Radio Tikrit from an American buff, began to make inquiries.

"Everyone here is completely mystified: Why would anyone name a radio station after Tikrit?" he said by telephone from Sulaimania in the northern no-fly zone of Iraq. "It's a very good way to turn off anyone who doesn't live in Tikrit, which is nearly everyone. It's worse than a bad joke."

Even more puzzling than its name is Radio Tikrit's evolving message. When it started up, the station railed against the U.S. and Britain as "ravens of evil," mimicked news reports on Iraqi media and featured a talk titled "Before It's Too Late" that urged Iraqis to prepare to battle America.

Gradually, though, antagonism toward Washington softened and praise of the Baghdad regime soured into criticism.

By last week, the station had completed a 180-degree turn. It denounced the Iraqi leader as a "tyrant" and lambasted his family, according to BBC Monitoring, a service that transcribes, translates and analyzes foreign broadcasts. The "Before It's Too Late" slot featured a letter from an "honorable officer of the Republican Guard" urging fellow officers to abandon the Iraqi dictator: "You would be fools not to realize the extent of popular wrath that awaits you if you do not leave this gang and flee."

This bizarre about-face, say radio aficionados, suggests that the station belongs to an exotic category of psychological operations known as "black clandestines."

Unlike the U.S. military's Radio Information broadcasts into Iraq, which make no secret of their affiliations and include recordings of Pentagon briefings, covert "black" stations try, for a time at least, to imitate features of enemy broadcasts. By shifting direction later, they hope to unsettle the enemy and even create the impression that former loyalists have changed sides.

It's unclear whether Radio Tikrit's flip-flops have had any impact inside Iraq. But they have flummoxed even professional radio experts listening from outside.

Four days after Mr. Fransson first detected Radio Tikrit's signal, BBC Monitoring issued a brief report describing "what appears to be a new Iraqi opposition radio station." Three days later, it declared Radio Tikrit "pro-government." After a two-week silence, it pronounced the station anti-Hussein. BBC Monitoring is an arm of BBC World Service, which is funded by the British Foreign Office.

Amateur radio buffs jumped on BBC Monitoring's zigzags and period of silence as evidence of interference by the CIA, which funds FBIS, an American monitoring service. FBIS collaborates with the BBC's service and provides most of its translations of Iraqi broadcasts. "It's very fishy," says Mr. Grace, the Washington-based clandestine radio hunter. A spokesman for BBC Monitoring says it "definitely wasn't leaned on."

Mr. Fransson, meanwhile, has returned to his closet to stalk new signals, but he hasn't caught anything interesting. The Radio Tikrit mystery just gets "bigger and better" and has been fun, he says. He thinks the station is "connected to America in one way or another" but he doesn't know to whom exactly.

For a hard-core DX-er, this is a big problem: He can't write to ask for an acknowledgement card to add to his collection. He sent an e-mail message to an Iraqi opposition radio station in London in the hope that it might lead him to Radio Tikrit. He isn't holding his breath.

"I'm basically a collector," Mr. Fransson says. "I like making contact with different people, but I don't know who these people really are."