BY PABLO BACHELET

WASHINGTON - Radio and TV Martí have officially launched their new aircraft-based broadcasts with a program sure to please their Cuban audiences -- baseball's World Series.

The new G1 twin turboprop, based in Key West, is to be airborne between 6 and 11 every night except Sunday in an attempt to bypass Cuban government jamming of the stations' previously stationary broadcasting facilities.

After several weeks of testing, the aircraft officially began beaming the regular Martí broadcasts Tuesday, starting with Game 3 of the World Series between the St. Louis Cardinals and the Detroit Tigers.

Although Cubans could rarely view the previous land-based broadcasts because of the government jamming, anecdotal evidence suggests some have been receiving the airborne transmissions, especially outside the Havana area, said the stations' chief of staff and spokesman, Alberto Mascaro.

''We did have some reports in the last few weeks of reception,'' he said in a telephone interview during a trip to Washington.

The Bush administration hopes the aircraft, which replaces broadcasting blimps once tethered in the Florida Keys but destroyed by hurricanes, will prove a more robust platform for defeating the Cuban jamming. Some Cuban-American activists have long lobbied for the shift to aircraft.

But the aircraft is still restricted to flying within U.S. airspace to avoid violating international broadcasting regulations. Some Cuban-American lawmakers are pushing the administration to let the plane fly in international airspace, which would make it even harder on the Cuban jammers.

The Cuban government has argued that all Radio and TV Martí broadcasts are illegal.

Last week, Cuba's acting ambassador before the United Nations, Ileana Núñez, told the General Assembly that on Aug. 11, Cuba detected simultaneous broadcasts from two aircraft in the 213 MHz frequency that interfered with island stations.

Mascaro said the new aircraft is broadcasting on TV's Channel 20 frequency and will not broadcast Radio Martí on the FM frequency. The plane is also capable of broadcasting live Martí signals.