MIAMI  —  Airline pilots departing from Miami International Airport are getting an earful of something unexpected: Hip-hop tunes from a pirate radio station that sometimes interfere with their communications with the control tower.

The music comes on a pair of frequencies from a station that calls itself Da Streetz.

"It's intermittent. Not all day, everyday," said Kathleen Bergen, a Federal Aviation Administration spokeswoman. "But clear communication between air control and the pilots is a critical part of flying."

Authorities traced the signals to an antenna at a nearby warehouse but did not find the disc jockey, although they did confiscate equipment including three computers and a CD player.

Despite that discovery and the seizures, the broadcasts have continued, authorities said.

Pilots who pick up the broadcasts switch to a different frequency to speak with air traffic controllers, Bergen said.

The FAA said it has conducted about 30 similar investigations of pirate broadcasts interfering with airport transmissions in the past decade.

The Florida Department of Law Enforcement is helping with the investigation under a state law that went into effect a year ago. The law makes it a felony to interfere with signals from licensed public or commercial stations, or to broadcast without a license.

Authorities said the owner of the warehouse had no idea the building was being used by an illegal radio station.