Broadcast engineers who died on 9/11 remembered: "Don't forget, we have people at the top"

For 25 years, we've paid somber tribute to the victims of 9/11. 

That includes broadcast engineers Isaias Rivera and Robert Pattison, two members of our CBS News New York family. 

They were at work on the 110th floor of the north tower, where the antenna and transmission mast kept New York television stations on the air. A total of six engineers who were up there died that day.

The heartbreak of the terror attack still resonates deeply a quarter of a century later.

That transmission tower was a trademark of the New York City skyline for years, says Jeff Birch, former senior vice president of engineering at CBS Stations. He worked for another New York station in 2001.

"Every picture you saw was the twin towers with the TV antenna up there, and then it was gone," he said.

That antenna on top of the north tower, at one time the highest point in New York City, was how millions of New Yorkers got their TV signal. Birch was in charge.

"The 110th floor was a mechanical floor," Birch said. "Everybody helped everybody. On the ground, we were all competing with each other for eyeballs. Up there, we're all one family." 

CBS News New York met with Birch at the National September 11 Memorial and Museum, where he saw for the very first time a 20-foot section of the antenna that was recovered from the rubble of the twin towers. 

"I didn't expect to see anything survive, come crashing down from a quarter mile up in the air. I'm very surprised this piece is here at all," he said. 

The original mast was over 300 feet long. 

"When you think about what they went through, and where they were working, got to give them a lot of credit, because they kept those transmitters going until the very last second," Birch said.

As soon as Birch learned of the attack, he reached out to the engineers, who had only a landline for communication.

"I called all the transmitter shacks ... to see if the guys were OK," Birch said. "The phone line went dead while I was talking to the second transmitter operator. I called the fire command desk, and I said, listen, I know you guys have your hands full, but don't forget there are people up on 110 that are trapped. And his answer to me was, we know they're there, we just don't know how we're going to get to them."

Part of that conversation has been memorialized, with Birch's quote as part of the museum exhibit: "Don't forget, we have people at the top."

"The building catches fire, didn't collapse immediately. So those poor guys were up on 110 wondering what happened, and then the bottom drops out from underneath them," Birch said.

He said he felt helpless. But almost simultaneously, his TV instincts kicked in.  

"We were TV guys, and our job was to get TV back so that we could inform everybody else in New York what was going on. So that was the driving force, get television back on the air, and to show the terrorists that they weren't going to stop us," he said.

Most New York stations were knocked off the air when the tower collapsed. CBS was quickly back on with their backup signal from the Empire State Building.

Today, Birch still keeps a hand in various operations as well. He says he's more comfortable under the antenna on the roof of the Freedom Tower than in the museum, looking at once was while always remembering Isaias Rivera and Robert Pattison, and all the men who sacrificed to make it happen. 

"Every time we come up here, we think of them. This is really the monument to them," he said.