Reporters are tough to nail.

When attempting to portray a character, any character, I try to get a handle on him any way I can. The "method" I was taught by Lee Strasberg was: Use anything that helps. The area I have found most useful has been the character's profession. It tells me a lot about the person's life-quickly. With journalists it just didn't work.

Doctors are easy.

When I got the part of Senior Resident Brubaker in Paddy Chayevsky's "Hospital" I was terrified. The responsibility of playing the most capable, knowledgeable of all residents, the man who had to answer to the Chief of Medicine (George C. Scott) was almost overwhelming. I flunked high school physics.

But I went to the nearest hospital, stopped the first doctor I saw, and within an hour I had handle: chronic fatigue.

Doctors lean all the time.They dont' sit, they col lapse. They walk an average of five miles on their daily rounds, and their life expectancy is five years less than that of the average man.

I spent weeks following them around, but in that first hour I got the clue that affected the staging of that scene with scott. I told him about my research and my wanting to do the scene leaning. He said, "Bob, you'll have a wall if I have to build it for you myself."

When I played a junkie on "Police Woman" I spent the weekend at Synanon in L. A. and learned enough to be specific and somewhat confident using as my handle the symptoms of the worst flu I ever had in my life, a flu with chills and sweats so extreme I thought about making out a will.

I've portrayed lawyers; alcoholics, hillbillies and various subterranean characters, including Donald Segretti in "All the President's Men."

But when I got the part of Joe Rossi, investigative reporter for Lou Grant's paper, I found myself in big trouble.

If I had to define "acting" in one word, it would be "behavior." And up till now every profession I had researched had distinct patterns of behavior common to all its members.

But after I followed some reporters around for a few weeks all I could use was a line from "The Sting": I came here to learn from you, but I already know how to drink."

As the shooting approached, my anxiety increased. Every reporter seemed to have a different style for everything. I had a dozen different ways to "get past the secretary," for example.

To tape or not to tape became a viable question.

"Note-taking sometimes clams people up," I was told, "try to remember and write it down later."

"Take good notes. It'll save your a-," another said.

I pressed on as deadline approached. There seemed to be no rules other than Be Good and Get The Story.

I tried sitting at a desk in the city room of the Los Angeles Times and typing. I had great difficulty concentrating. Not only was it noisy, the room was enormous. And there was no privacy. I felt like a student taking an exam in a gigantic study hall. AHA! Not necessarily "Eureka," but, at least, "Aha."

It was a subtle discovery, but it was something. These people are like students whatever their ages. They sit at desks, do intense research, turn in papers and have them corrected and marked.

Shooting of the "Lou Grant" show began with Rossi and me still somewhat at sea.

I placated myself by continuing my research and observations. Over the past year and a half I learned much. About a passionate, intense, pressurized profession. About a group of people who seem to be on some kind of mission, trying to change the world for the better. At times their egos make actors look like Trappist monks. Alcoholism and "burn-out" are accepted occupational hazards. Most can make much more money in other writing-related fields, like advertising. And they know it. But they don't. They remain journalists as I remain an actor. Why? I guess because they care.

As I sit here at one of their desks with a borrowed typewriter, checking the clock, drying my hands with my hair and kicking myself for getting sucked into this mess in the first place, I ask myself, why?

I guess it's because I care. CAPTION: Picture 1, Robert Walden, by Frank Johnston-The Washington Post; Picture 2, Robert Walden, by Gerald Martineau