NEW YORK – The Big Four TV networks are expected to see a 12.5% revenue gain this year, well ahead of earlier projections, but the growth rate in 1997 will prove just a third that large.New figures from broadcasting and ad prognosticators, released at the annual PaineWebber media conference Monday, show the major networks far outpacing most other media, buoyed by NBC’s $780 million summer Olympics windfall and spending by political campaigns. The major networks will see a 12.5% increase, the first double-digit gain since 1984, to $13.05 billion for the year, while national cable ad revenues will grow at 25%, off a much smaller base, to $3.34 billion, according to Robert Coen, senior VP, forecasting, at the McCann-Erickson ad agency. Syndication revenues will be up 8% to $2.18 billion. But in 1997, “television will be hard put to build much growth upon the strong gains posted this year,” except for cable nets, whose growing numbers will fuel aggregate gains, Coen said. Early forecasts for the coming year show the Big Four gaining just 4%, to $13.57 billion, with cable and syndication’s tally growing 15%, to $6.34 billion. Encouraging figures Still, the results are encouraging, even after accounting for the normal quadrennial boost that the Olympics, and on a local level elections, always provide. And in what’s believed to be a first, combined TV ad revenues this year will exceed those from newspapers, long a dominant ad category. David Poltrack, exec VP of planning and research at CBS, had predicted a 9.5% gain this year, but Monday revised that figure to 12%, crediting the strong Olympics ad market but noting that without it, “the underlying year-to-year gain was still a healthy 5.5%.” Poltrack predicts another 1% to 2% uptick next year, which translates to an underlying gain of 5% if the Olympics are discounted. But increasingly, the TV business is becoming a case of the haves and have-nots, said Betsy Frank, exec VP at Zenith Media Services, also speaking at the conference. “The media-buying marketplace has become increasingly polarized, with the top-tier, high-rated high-profile shows” like NBC’s “ER” and “Seinfeld,” commanding ad rates at huge premiums vs. other “nonhits,” which she said are still valuable to buyers “because they help us find cost efficient ways of buying network television.” Method criticized Despite Poltrack’s rosy review of the year, he spent much of his presentation decrying what he described as Nielsen Media Research’s measurement flaws, repeating earlier claims that sample changes and panel cooperation rates have hurt combined network ratings. Still, he conceded, not all of the major networks’ continued audience erosion can be explained away, but he also downplayed the significance of both computer usage or most individual basic cable networks as a major factor, and Poltrack repeated a claim that no competitor has yet presented a viable alternative to the reach of network TV. Overall, Coen expects national ad spending to come in at $102.08 billion this year, up 8.3%, rising at a slower 5.8% pace in 1997, to $107.96 billion. In other broadcast media, revenues from national advertisers for spot TV will climb 8% this year, to $9.85 billion, and 4% in 1997, to $10.25 billion, while radio will rise 6% this year, to $2.59 billion, moderating to a 5% gain next year to $2.72 billion.