New York's major TV stations — which have been substantially off the air to homes without cable TV — are expected to resume broadcasting on their regular over-the-air channels this week.

But the potential cost of Tuesday's World Trade Center tragedy could be more than $60 million for stations. For viewers, it may mean that TV reception will never be the same again. 

Of the 10 stations that were blasted off the air by the collapse of 1 World Trade Center, at least four will resume transmissions from the relatively remote — and shorter — Armstrong radio tower on the Palisades at Alpine, N.J. 

Two other stations are installing transmitters and antennas atop the already-crowded Empire State Building — the original home of New York's TV stations until the taller World Trade Center was completed in the early '70s. 

"We figure we're losing about 30 percent of our audience, so we have to get back up soon," said WNET's Stella Giammasi. 

"We're only on cable now," said James Clayton, who manages both WNYW and WWOR for News Corp., which also owns The Post and Fox News. "We hope to be on the air by early [this] week." 

WCBS was the only major station that continued to broadcast over the air on its usual dial position because it has always maintained backup transmitters on "Empire," as engineers call it. 

Normally, it's not easy to quickly obtain high-powered TV transmitter and antenna systems that together cost as much as $2 million, according to Harris Corp., the leading manufacturer. 

Each of the seven big VHF stations had two antennas and four to six transmitters at the World Trade Center  analog and digital (HDTV) systems with their respective backups. 

"We essentially stopped production at our factory of anything that interfered with restoration of service for our New York customers," Harris VP Dale Mowry told The Post

Mowry says all of the city's station managers  usually a fractious and highly competitive group got together on "a common call" with Harris and other manufacturers to coordinate their needs. 

"It was New York broadcasters uniting to get the city back up," Mowry said. "You should be proud." 

The estimated 25 to 30 percent of local viewers who bypass cable and satellite TV for rooftop antennas or rabbit ears may need to reorient them. 

The relatively weaker signals emanating from the lower and more distant Alpine tower may not improve any time soon because the Empire State Building  which also accommodates about two dozen FM stations has little room for additional bulky TV transmitters, not to mention more antennas on its already-jammed tower. 

An irony of WNBC's move to Alpine is that it will rely on the tower built by Edwin Armstrong, widely credited as the inventor of FM radio. 

In 1954, Armstrong jumped to his death from his River House apartment after a lengthy battle with RCA and NBC over FM patents left him nearly broke.

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