When Ted Turner's much ballyhooed all-news television network finally goes on the air tonight after months of hype, the premiere will be greeted with almost universal skepticism both by the TV and financial communities alike. Called the Cable News Network, it will use satellites to beam broadcasts from its base in Turner's hometown of Atlanta to cable stations around the country.

Cable News Network is counting on an average of 40,000 American homes to be tuned to its programs round the clock, and about 120,000 homes during the prime time hours from 8 p.m. to 10 p.m.

In the Washington area, cabel channel 12 in Arlington will carry CNN.

The venture will rise or fall on the whims and the staying power of its orginator, Turner, a brash, outspoken entrepenueur who enjoys thumbing his nose at the Establishment. The 41-year-old Turner, known as the "Mouth of the South" as well as other even less pleasant appellations, has been openly critical of programming by the three large networks. He has even suggested that his CNN news hawks will expose evil-doing by the Big Three.

"It's only the broadcasting establishment that doesn't like me," Turner recently told the establishment organ, Broadcasting magazine. "They're pea-green with envy."

The quotably controversial Turner aside, CNN's chance of success strictly from a dollars-and-cents perspective has to be seen as a crapshot. It's a pipe-rack operation in an industry notorious for its high overhead.

CNN's budget, for example, is $25 million for the first year. By contrast, CBS, NBC and ABC each are said to spend between $100 million and $1150 million a year on their news operations. And while the three networks could fill volumes just listing their advertisers, CNN goes into business with just 17 advertisers signed up.

But even those who are openly critical of the CNN scheme and claim it is doomed from the start have to admit that they have very little evidence on which to base their opinion. On the other hand, neither has Turner much evidence on which to base predictions of success because what he is doing has never been tried before.

As nearly everyone knows by now, Turrner started to build his personal fortune -- estimated by one of his financial executives at about $130 million -- when at 24 he took over his father's failing advertising agency and turned it around.

In the late 1960s, he acquired another losing business, Channel 17 in Atlanta, by assuming debts of about $2 million. That station, called WTBS, became Turner's "super-station" when he began to use satellites to beam programs from it to other ultra-high-frequency TV stations across the country.

According to the annual report of Turner Broadcasting System's annual report, that station now is worth $69 million. Along the way, Turner picked up a UHF channel in Charlotte, N.C., again by assuming debts of $1.2 million. Recently, he sold the Charlotte station to Westinghouse for $20 million.

Turner, who obviously loves the limelight, has become a sports impresario by buying major interests in Atlanta's professional baseball, basketball and soccer teams. He also won the last America's Cup race skippering his own yacht.

William Bevins, a former accountant with Price Waterhouse who joined TBS last August as vice president-finance, says that Turner's leading creditor for CNN -- to the tune of about $8 million -- is First National Bank of Chicago. That bank has been backing Turner ever since he took over his father's failing business. TBS also is making a private offering of a small amount of stock to raise about $10 million for the venture.

As for Turner's personal stake, he owns 87 percent of the outstanding stock in TBS, says Bevins, and he is plowing his profits back into the company. He also plans to use his profit from the sale of the Charlotte station to help finance CNN.

The advertising CNN has lined up seems to have sold, in part at least, on the basis that the news would complement the pitch.

For example, Campbell Soup Co. in August will begin sponsoring a cooking segment. Sharp Electronics, the calculator manufacturer, will underwrite a financial news report each night from 7 to 7:30.

Bristol-Myers Co., the networks biggest ad contract so far, has signed up for a full year. The pharmaceutical manufacturer will sponsor "News From the World of Medicine," which will run 44 times a week at roughly fixed times each day.

This seems to make the programming vulnerable to interference by the sponsor. For instance, it seems unlikely that Bristol-Myers would be particularly happy to seek CNN do a hard-hitting investigation of the drug industry. And with so much at stake, it also seems unlikely that CNN would undertake such an endeavor.

The news network, which operates from a properly Southern-looking former country club on a 20-acre site in Atlanta, will be fed the news from 20 full-time reporters in six U.S. cites, London and Rome. Where CNN does not have full-timers, it has lined up part-timers or stringers.

CNN is primarily a nonunion operation, which gives Turner more flexibility in staffing and technical innovation.

The incoming news to Atlanta will bounced off Western Union's satellite, Westar. Outgoing news to the cable operators will be beamed off RCA's Satcom I.

The first meaningful measure of how Turner's daring venture turns out will come in November, when the Nielsen organization sweeps the country to find out who's watching what out in videoland.