Wall Street may declare it impossible, and CBS may be saying "no way" -- but those who know R. E. (Ted) Turner warned yesterday that he has become a very rich man making deals that the establishment decreed foolish or off-limits.

When "Terrible Ted" -- as he was known in the sports world -- announced that he would create a nationwide superstation from Atlanta, the establishment smirked. When he bought the bad news Atlanta Braves in 1977 for $12 million, his friends offered condolences. When he said he was going to create a cable network, the television people openly guffawed.

And even though he has not always done well, Turner is now fearlessly, some say recklessly, going for one of the big three -- a $3 billion bid for CBS.

"He shouldn't ever be underestimated," warns a fellow Atlantan, Rep. Wyche Fowler (D-Ga.) "I'd be surprised when all the dust settled that he didn't take over one network, but all three."

"Whatever you tell him cannot be done, that is what he will do," Fowler said.

Media experts have begun trying to assess what a Turner takeover of CBS would mean to the network specifically and the news business in general.

Turner's own comments about the way the three big networks have done business are not comforting to the news operations in CBS. As one producer put it yesterday afternoon: "I'm just trying to work and pretend it isn't going to happen."

Although, when he announced his bid for CBS, he said he had no association with anyone of any political stripe, Turner's views on good versus bad news are fairly strong and unambiguous.

"In my opinion, the greatest enemies that America has ever had -- posing a greater threat to our way of life than Nazi Germany or Tojo's Japan -- are the three television networks and the people that run them, who are living amongst us and constantly tearing down everything that has made this country great," Turner said in one recent speech.

In a Playboy interview several years ago, Turner also said: "The network news is just half an hour of gloom and doom, with a few sports scores interspersed. I don't think that's public service," he said.

"The way they present the news, I think it does more damage than any entertainment program," he said, mentioning such entertainment programs as the "I Love Lucy" reruns that are a staple of his Atlanta SuperStation WTBS.

In the same interview with Peter Ross Range, Turner said that his "low-budget Walter Cronkite" news anchorman sometimes reads only the Associated Press wire.

"If he comes to a story he doesn't like, he'll say, 'Oh, that's too awful, I'm not going to read that,' and he'll throw the copy over his shoulder," Turner boasted.

If such talk is not encouraging to the news side of CBS, however, some of those who have worked for CNN said that Turner, nicknamed "The Mouth of the South" for his all-talk personality, is more bark than bite.

Dean Reynolds, former CNN White House correspondent who is now with ABC, said, "I never got the feeling that he was so much interested in the news-gathering aspect as much as he was interested in owning the vehicle.

And Daniel Schorr, whose contract with CNN was not renewed, said: "Most of the time I was hardly aware of his presence. He would come in with several ideas that he would outline, and then we would go our own way."

However, Turner has pushed his "SuperStation" to add programming that he considers important. For example, Turner, whose politics are described by one associate as "erratic," feels very strongly about the problems of nuclear disarmament, according to friends. As a result, WTBS has shown two British films on the devastation that would be caused by nuclear war.

Although considered a conservative and applauded in his move against CBS by some conservative groups, Turner has boasted that he has enjoyed duck hunting with Fidel Castro.

Says Schorr: "Conservative is too narrow a word for him. He is a bundle of contradictions."

His life, even at 46, is the stuff of novels. Born in Cincinnati, he came south with his family and was quickly sent to the places where Southern parents send troublemakers -- two military academies.

He was suspended twice when he was at Brown University and suspended from his fraternity after he set fire to the homecoming float.

Turner has told friends that at age 24, he was sailing when he learned that his father had sold the family billboard business and killed himself.

Turner bought back the company and began to build his empire. His next move was for Channel 17, a UHF independent station in Atlanta. When I bought that, everybody just hooted at me," he told Playboy. "We lost $2 million in the first two years . . . but now we're socko."

Analysts have estimated that Turner Broadcasting System Inc. may be worth as much as $500 million. Turner owns about 80 percent of the company, which owns both the Braves and a controlling interest in the Atlanta Hawks, a basketball team.

Turner, who clearly loves being at the top and mingling with the famous, is not awed by those in power. One friend says of him, "He fears nothing, nobody."

Last week, when former presidents Jimmy Carter and Gerald Ford hosted a seminar on arms control in Atlanta, Turner was spotted at a dinner sitting between Ford and Henry Kissinger. Listening to the problems of the world with one ear, Turner had turned the other ear to a mini-television set so that he could watch his Braves play.

Turner has enough energy to excel in more than one area. He is known to many as the captain of the sailboat that won the America's Cup in 1977.

For the loquacious Turner, there was a special poignancy yesterday when -- using CNN to announce his takeover bid -- he told reporters that until the CBS affair is over, one way or another, he wouldn't be able to talk about it publicly.

"For 30 or 60 days, you won't be hearing from me again," he said, adding "as difficult as that will be."

Said his corporate spokesman Arthur Sando, "He doesn't want to blow this thing."