It was the format change that was so obvious that it only took six years. Top 40 fans expected Clear Channel to take Baltimore’s 104.3 FM from Classic Rock to Smooth Jazz in 2003. They got their hopes up again last year, only to have the station choose gold-based Alternative as WCHH (Channel 104.3). So it was inevitable in this up cycle for Mainstream Top 40 that Clear Channel would finally launch, as it did today at Noon, the new Z104.3. It’s the third round for Top 40 on the frequency that most notably housed WBSB (B104) from 1980-92.

Technically, Baltimore has been without a CHR since WXYV’s relatively brief run at the format ended in the early ‘00s. Since then, however, Adult Top 40 WWMX (Mix 106.5) has done well by covering both the Hot AC and Mainstream position.

On its first day, Z104.3 was running the now-familiar jockless “10,000 songs in a row” and using the also-customary “All the Hits” positioning. Other liners: “All About Hit Music” and “If It’s A Hit, It’s In There.”

Here’s Z104.3 at 2 p.m. today:

Jay-Z/Rihanna/Kanye West, “Run This Town”

Boys Like Girls, “Love Drunk”

Sean Kingston, “Fire Burning”

Lady Gaga, “Paparazzi”

Beyoncé, “Single Ladies (Put A Ring On It)”

Kings of Leon, “Use Somebody”

Justin Bieber, “One Time”

Taylor Swift, “Love Story”

Rihanna, “Hard”

Jay Sean, “Down”

Cascada, “Evacuate the Dancefloor”

Cobra Starship, “Good Girls Go Bad”

And here’s Mix 106.5 at 5 p.m.

Three Days Grace, “Never Too Late”

Jay Sean, “Down”

Rob Thomas, “Her Diamonds”

Rihanna, “Russian Roulette”

Black Eyed Peas, “I Gotta Feeling”

Green Day, “21 Guns”

Kings of Leon, “Use Somebody”

Pink, “I Don’t Believe You”

Usher, “Love In This Club”