Ralph Renick, the longtime news director and anchorman at WTVJ in Miami, is something of a hero among the nation's 1,200 news directors.

A few years ago, responding to a growing trend in television news, WTVJ's management brought in the nation's largest TV consultants, Frank Magid Associates, to analyze its news operation - despite the fact that Renick's show had been No. 1 in the rating in Miami for about 20 consecutive years.

Among Magid's recommendations was that the name of the 6 p.m. news show be changed from "Ralph Renick Reports" to something catchy like "Action News."

Renick, who is also a vice president of the station and holds stock in Wometco, its parent company, blew his top, went to his bosses and had the decision rescinded, although other Magid recommendations were accepted.

That story warms the hearts of more than a few news people. To them it's a rare victory by a broadcast journalist over the gimmicks that many news people resent - and the hiring and firing that sometimes follows a consultant's arrival on the scene.

With its intense competition and big-money stakes, TV news is a high-strung profession, given to eternal tinkering, with packaging and with its people (average tenure for a news director: 2.6 years) in the search for a winning formula that will make a station's newscasts No. 1.

Since mistakes can be costly and take years to overcome in this impatient industry, station executives (many with backgrounds in sales or marketing)have been willing, even eager, to pay well for outside help.

Enter the consultant, by now a fixture of the high-risk world of TV talent, a placebo for worried managements, an expert adviser who can help fine-tune a winning newcast or become an indispensable crutch for a faltering or inept news department.

A consultant can, in fact, have considerable impact on how the news is presented. Sample recommendations: New hairstyles, slicker studio sets, a "charm school" for promising talent, how to hold a pencil during newscasts, analysis of viewers' preferences (or biases), shorter story lengths, faster pacing, creation or sharpening of a show's "identity," introduction of packaged health or consumer features, even a critique of the between-story banter on the set that is considerably more studied than viewers may suspect.

In Washington, WMAL has used McHugh-Hoffman, Inc., in the past and the McLean firm is reportedly negotiating (for a reported fee of $43,000) to catch on again with Channel 7.

WTOP officials say they've never used a consultant. WRC hired Magid once but ultimately shelved the results.

Opponents of the consultants' methods, led by CBS anchorman Walter Cronkite and correspondent Charles Kuralt, have become increasingly critical of such intrusion and the "cosmetic" results of their recommendations.Others inside TV journalism think the impact of consultants is overrated. But good guy or bad, a consultant affects what viewers see on their screens when they tune in the local news. And none is bigger in the business than Frank Magid Associates.

Magid himself is amused by the Renick anecdote, which he has heard many times, and he smiles a millionaire's smile when he is told that even Renick considers him to be a "charmer" and the "best damned salesman" he's ever met.

At 45, Magid has the handsome deeply tanned looks of someone who skis frequently at Jackson Hole., sails the Gulf of Mexico and yachts with wealthy clients in the Caribbean.

He was born in Chicago, majored in social psychology and methodical stitistics at ehr University of Iowa and taught sociology there for three years. He also taught statistics and anthropology at Coe College for two years. All of which served him well when in 1957 he started a research firm in Marion, Iowa, a business he later expaned to include TV consultancy.

In 20 years, he has become a businessman of wealth and some power, a financial winner in TV, one of America's greatest growth industries of all time. However controversial he may be, he is sought after by local stations that themselves have been described as a failure-proof way to make money.

He operates from his headquarters in Marion, has 105 employees and about 100 client stations. It is a clentele bigger, he says, than that of his five major rivals combined, although he refuses to reveal his cutomers. (McHugh-Hoffman, Inc., of McLean, with 10 employees, is the second largest.)

And his influence is felt among television people.

"Jeez," says the news director of one of the country's 10 largest stations as he refuses to be quoted by name on the subject of Magid, "any one of those consultant firms can put the black mark on you and you're through in this business."

"Consultants do influence trends in television," says another. "I know stations that hire Magid just so no one else in their market can have him and that's kind of power right there."

It's money talking, among other things. Magid's fees range from $10,000 to $65,000 annually for what Cronkite dismisses as"a fad" and "balderdash."

Stell, Magid hears his critics talking. There is irritation and perhaps a hint of contempt in his voice when he replies to some of the charges against him.

He becomes testy when it is suggested that his viewer research amounts merely to giving the public what it wants.

"People don't know what they want," he says. "I is a very, very complex process. Audiences are different from city to city."

And of journalists who say that Magid imposes a rigid formula for story-lengths in the news: "They've heard each other tell the stories so often they've begun to beleve them. I understand it, but it irks me just the same."

But he saves his real sarcasm for his biggest critic, Cronkite:

"I feel sorry for Walter because he doesn't take time to check the facts," he says. "It's interesting that TV newsmen are so gullible."

A television consultant is part traveling salesman with a trunk full of samples, part "show doctor," like a theater director brought in to save an ailing production. And like both, he is never anxious to reveal the tricks of his trade.

"There're five guys out there who's love to know what we do," says Magid protectively.

Because his clients are spread across the country, though, Magid is in effect a clearing house for production ideas and available talent. That in itself is a saleable service.

One East Coast affiliate, seeking to replace its weatherman recently, saved itself the time and expense of traveling or calling around the country by contacting Magid in Iowa. Magid's firm promptly mailed off a videotape containing samples of 20 weatherman's work collected nationwide, and the East Coast news director was able to make his choice without leaving his desk.

Even that raises some fears about consultants' ethics in the hypersensitive World of TV news. A consultant could use his unique position to interest a Chicago station, say, in a Dallas Anchorman, and thus ease the presure on his stumbling Dallas client. But Magid denies such charges categorically, and in fact none check out.

A station that buys Magid's whole range of services gets everything from polling to final polish and promotion campaigns. A team of Iowa-based staff members walks through the city's neighborhoods and shopping centers, conducting as many as 1,500 interviews in a metropolitan area the size of Washington. Those querled are not only asked probing questions about the client station's news show and its talent, but are shown pictures of rival reporters and anchormen for comparison. A Magid expert also may be detailed to watch specific newscasters with a critical eye.

When the polling is finished, printed reports analyzing the research findgins are submitted to the station. (WRC, when it hired Magid, received four thick looseleaf notebooks).

And if the station wishes, there will be specific recommendations for hiring and firing - the aspect of consultancy that gives broadcast journalists sleepless nights.

Even without firings, individual anchormen or reporters may be taken aside for private consultations and told how the station's viewers react to his or her on-air delivery, clothing or looks, an exercise in massive approval or rejection that many, understandably, do not look forward to or appreciate.

But news executives, at least the more confident ones, like it. They point out that an outside observer with a fresh eye can pick up nuances that even they may not have noticed. And station managers, pressed by owners for results, can cite the consultant as a sign that wise decisions are imminent.

Magid, meanwhile, is prosperous enough to be philosophical.

"I can't get angry at these people for saying things or claiming things about us," he says. "There's an ego problem involved, undoubtedly.

"News directors feel threatened, maybe, but our interest is not to make the news director at a station any less. It's to make him a lot more."