Sunday's 50th Super Bowl is expected to attract more than 120 million American TV viewers. To satisfy such an enormous and demanding audience, CBS will employ 70 cameras and 250 microphones to capture, scrutinize and, if necessary, replay virtually everything that happens at Levi's Stadium.

The year's most anticipated football telecast, Super Bowl 50 will be the most sophisticated ever, the 2016 version of a constantly evolving species that emerged from the primordial ooze 77 years ago.

The first televised NFL game happened on Oct. 22, 1939, a meaningless matchup of two bad teams, the Eagles and Dodgers, at Brooklyn's Ebbets Field. Outside of the small crew and relative handful of viewers, no one, not even the players themselves, knew the game was being televised.

Statistically, for a medium that would forever change sports and how it was perceived, the debut was unimpressive: an eight-man crew, two cameras, one microphone, and zero monitors, spotters, color men, or commercials.

The game itself, a 23-14 Eagles loss, meant little in the standings. Hardly anyone saw the telecast. And no one recognized its importance, not even the New York Times, which failed to mention the game's groundbreaking significance in its story the next day.

In fact, the most interesting aspect of that Sunday afternoon broadcast may have been its announcer.

Allen Walz, 30, was a New Yorker who had been a Golden Gloves boxing champion and an outstanding rower. A graduate of the Hun School and NYU, he worked for the Dale Carnegie Institute before, in 1934, establishing the rowing program at Manhattan College.

A naval officer in World War II, he rose to lieutenant commander, earning a bronze star when, commanding a destroyer escort on D-Day, he rescued 100 soldiers whose transport vessel had been sunk by German fire off Normandy Beach.

Following the war, Walz coached rowing at Wisconsin and Yale. He also was, according to the book Cloak and Gown by Robin Winks, a secret CIA recruiter who persuaded hundreds of postwar collegians to sign on with the spy agency.

"Once every three weeks he would meet with a CIA agent at the reflecting pool in Washington, passing on names and evaluations," Winks wrote.

But for that Eagles-Dodgers game, Walz was practically anonymous, sitting with a microphone in his hand and his chin on the railing of a balcony box as he strained to follow and report on the dim action below.

"When the sun crept behind the stadium, there wasn't enough light for the cameras," Walz recalled to football historian Jim Campbell shortly before his death in 1990. "The picture would get darker and darker, and eventually it would be completely blank, and we'd revert to a radio broadcast."

Hand signals

Just before World War II, which stalled research into TV, companies such as RCA and Philadelphia-based Philco experimented with the new technology at sporting events.

In 1939, RCA televised several New York-based events - college baseball in May, a heavyweight fight in June, a National League baseball contest in August, and a September college football matchup between Fordham and Waynesboro.

Meanwhile, in 1938, Philco had broadcast several Penn football games though there were perhaps only a half-dozen sets in Philadelphia.

By the time of the Eagles-Dodgers game, fewer than a thousand New Yorkers owned TVs. That day another few hundred viewed it from the New York World Fair's RCA Pavilion.

Early that autumn Sunday, a truck parked outside the Brooklyn ballpark. Once inside the home of baseball's Dodgers, workers set up two iconoscope cameras, one behind Walz in a mezzanine box, the other fixed on the sideline between the 40- and 50-yard lines.

"I did my own spotting, and when the play moved up and down the field," Walz said, "I'd point to tell the cameraman what I'd be talking about. We used hand signals to communicate."

Much of his information came from the 10-cent game program, which featured Dodgers tackle Frank "Bruiser" Kinard on its cover.

During the game, Burke Crotty, the producer-director, was stationed in the parked truck. The images and pictures he sent from Ebbets Field were relayed to viewers on New York's W2XBS via a transmission tower atop the Empire State Building.

The 1939 Eagles, despite rookie quarterback Davey O'Brien, were en route to a 1-9-1 season. The Dodgers would finish 4-6-1. These teams had played to a spiritless 0-0 tie three weeks earlier in Philadelphia - before 1,880 in cavernous Municipal Stadium - and only 13,157 fans showed up for this meeting, a modest gathering but still larger than the 1,000 or so who saw it on TV.

The struggling NFL was willing to try anything. It lagged badly behind college football in the public's imagination. Two weeks later, for example, 75,600 fans crammed into Yankee Stadium to see Notre Dame top Army, 14-0.

They were unaware

For the victorious Dodgers, three Ralph Kercheval field goals - including a 45-yarder that was the NFL's longest that season - provided the winning margin. Bert Bell's Eagles scored on Franny Murray's short run and on a pass from O'Brien to future Hall of Fame end Bill Hewitt, the last NFLer to play without a helmet.

Asked years later about their role in the historic telecast, players on both teams said they'd been unaware it was happening.

Despite the small audience and a $25 paycheck, Walz took his task seriously.

"We decided right away that the way to do television was to comment on the game, not tell what was happening like we did on radio," he said.

After the game, Walz rushed down to the field for interviews.

"But it was too dark by then to do television," he remembered.

And so, he and his seven fellow employees packed up their equipment and exited the old stadium, unaware that they'd just fired the first shot in a revolution that would transform America.

"Nobody," said Walz, "had any idea where this would lead."

ffitzpatrick@phillynews.com

@philafitz