She said she was calling from Southeast. She wanted to hear some thing by Stevie Wonder. And she wanted an answer.

"Are you black or white?" she asked Jeff Leonard.

Leonard smiled. "White," he said.

"Now," she scolded, "don't you lie to me . . ."

"Hey, we wouldn't be No. 1 with just black people," says Jeff Leonard, speaking of his employer, WKYS-FM, the city's most-listened-to radio station. "We have a lot of closet white listeners."

Leonard might know. He works in a room no larger than a closet--and though a lot of people think otherwise, he ain't a brother.

He's just heavy.

At 35, and after 10 years on the air in Washington, Leonard is the city's No. 1 radio voice in the afternoon. From 2 until 6 most days, he sits in a tiny studio with walls of scarred acoustic tile and posters of primarily dark-haired, somewhat-clad women, and talks to us. He is both funny and funky, big-time in small doses, his voice a baritone sax weaving playfully among bumptious, black-white music by Diana Ross and the Doobie Brothers, Instant Funk and Elton John.

Leonard goes with the music: sexy and full of brass. He is blessed with a great little casual laugh, which he dispenses at precise intervals in his carefully paced show.

"He's just . . . earthy," says one 27-year-old professional woman, a native Washingtonian who has a button on her car stereo tuned to guess who. "And his voice is very, very seductive."

"Hey, 3:29 on a Friday," Leonard says, sidling over the introductory thump, thump, thump of a song that has him rocking in his chair. "Too warm to snow but it's predicted. This one's by Ambrosia: 'Biggest Part of Me.' " He pulls back from the mike slightly, then tilts in again, two thumps and a cymbal away from the vocal. "Didn't know you could write a song about it . . ."

Leonard, like his fellow deejays at "kiss," as the station likes to advertise itself, thinks radio reflects trends-- it doesn't set them. Of his own on-air, offhanded wryness, he says:

"I may not be the funniest guy in town, but if I can get a half-smile out of somebody, I feel I've done my job. I don't want to be a Howard Stern, to offend as many people as I possibly can. Those kind of guys, in my experience, are hot for a little while, but . . . how long do those guys last? They're in and out of town, ree-yul fast. I decided not to go that route.

"I want to sound intelligent and . . . hip," he says, leaning forward for emphasis. "Hip. Y'know, you can be both hip and intelligent. It always was that you're either an egghead or you're talking jive or something. There's a middle ground, and God, this radio station is the personification of that middle ground. I mean, we're walking right down the black- white thing, y'know? And it's working."

In keeping with WKYS' rise from the ratings cellar six years ago, when its all-disco, no-personality sound was earning just a two percent average audience share, Leonard and the rest of the station's staff will move this summer into new studios-- with windows--that NBC has built at its squat fortress near Ward Circle.

WKYS is one of 14 radio stations owned by NBC. None of the others is a No. 1 station in its market; New York doesn't mess much with WKYS' on-air sound.

yy y

11,.11 Elsewhere in Washington's radioland, stations are fighting a heated, remote-controlled battle for the disposable incomes of the coveted 18- to 34-year-old market. They tickle our fickle natures with dimestore Wolfman Jack and Don Imus impersonators, with commercial- free promises--Never Less Than Three Songs in a Row (but never more)--with a "better music mix," with "Washington's best rock," and with the deejay of the decade, the ubiquitous less talk.

"Nah, we don't do that," says Leonard, who talks--or parries, rather--every hour with newsman Joe De Capua, and whose occasional studio interviews are more memorable than any 10-times-an- hour jingle.

"I wish I could describe the way you're dressed," Leonard said not long ago to George Clinton, Dr. Funkenstein himself, the jive-talking, flak- jacketed singer of Parliament-Funkadelic fame. "There's too many zippers for me to comment--zippers everywhere . . ."

"Oh yeah, the police stop you, see," said Clinton, "they get tired of searchin'."

yy y

11,.11 For about a year, WKYS-- without promising to rock anybody's nation or ever concocting an on-air slogan or a TV-ad campaign--has led the city's nearly 40 other radio signals with close to a 10-percent share of the average audience, according to Arbitron.

The rise apparently was done by capitalizing on the increasinmg number of so- called "crossover" musical artists like Hall and Oates, Al Jarreau, Michael Jackson, and Steely Dan, and yes, the 6-foot-2, basketball-playing crossword-puzzle artist himself, Jeff Leonard. One and all, they work together.

Less than a mile away on Jennifer Street NW, the troops at WMAL-AM are also working-- Harden and Weaver, Trumbull and Core, the Redskins' radio team, one of the city's best broadcast news departments--toward the day they regain the No. 1 spot WMAL has held for most of the last 20 years.

That is a struggle Leonard wants to win.

Both WKYS' staff and listenership are younger, hipper and blacker than both WMAL's staff and listenership, Leonard says. He thinks like WKYS program director and morning man Donnie Simpson, who banished the hype, demanded that deejays be themselves and picked the music that carried WKYS beyond disco into "disdat" ("a little of dis, a little of dat").

"I think we can be the next 20-year winner like WMAL, I really think that," says Leonard. "I don't think we're a flash in the pan. As long as we keep the personalities that we've got, and don't become a swinging door, as long as we keep the music viable--and music changes all the time, you know, we changed so subtly from disco that hardly anybody noticed, but it's totally different."

yy y

11,.11 Leonard grew up with rock 'n' roll--Hendrix, Beatles, Doors, a Woodstock child. At home nowadays, in the comfort of his Arlington condominium, he is likely to lean toward jazz--his idea of a natural progression from rock (which "they don't make like they used to"). He has a fitting fondness for that most sexy of solo instruments: the saxophone.

And over a strutting bass beat, he can wield his voice as well as Grover Washington Jr. can wield an alto.

"That's the kick of radio," says Leonard, talking about talking to the tune. It's as if his voice, says his engineer, Shirley Augustine, "is part of the music."

"And when you do it right," says Leonard, "and you kill that mike and the guy starts singing, and you just take the headphones off and you say"--his voice turns into a parody of itself-- "'Hey, that was dyno-mite. I'm smooth as silk.'"

Of course, the other kick of radio is getting premium pay ("Let's just say I'm still in five figures") for being a regular guy.

A smooth-as-silk regular guy, that is.

yy y

11,.11 "Jeff could always talk, that's for sure," says his mother, Julie Vetos, who remains in the small town outside Fall River, Mass., where her son grew up. "He could convince people of things even if he wasn't sure about it himself."

Leonard talked himself into radio in 1966, when he was in a seminary in St. Mary's, Ky., following Catholic high school in Fall River, days shooting hoops at the playground and billiards at his stepfather's pool parlor.

Leonard left the seminary after two years of struggles with self-doubt, but not before he joined the radio club.

Leonard and some club members put together a makeshift radio station--a bootleg, 25-watt, top-40 outlet helped along by "$1.98 turntables" and a local radio professional Leonard came to admire.

"I used tLeoo just watch this guy, who worked for ABC, and started to realize the magic that goes on between you, sitting in this room, and somebody who may be a hundred miles away--making them laugh, setting a mood, kind of a magic. It's really like circus sawdust; it gets in your veins."

After college in St. Louis, Leonard went to San Francisco to be a famous deejay. "They laughed at me," he says. He stayed in town anyway and became a hippie. "In those days you had to be a hippie," he says, half-seriously, "or otherwise they thought you were in the service or something and you didn't get any good dates."

Leonard was in the service soon enough: drafted. After 18 months in the Army, he went back home and got a job as a $100-a-week newsman near Fall River. In 1973, he landed a deejay slot at a Washington oldies station, WMOD-FM.

Leonard, once married, is attached these days to a '78 T-Bird, a mustache and, in the winter, to some pretty good skis.

He walked away from a head-on motorcycle crash two years ago on 34th Street NW with no more than a cut on his leg and a mouthful of mud--a lucky man.

And a ladies' man.

"You know, all our music is either about sex, or love, or getting love, or not getting love, or trying to get love," says Augustine, 31, who is Leonard's only "live" audience most days, across the thick control-room glass. "So that's Jeff--most of his comments are about the song. He comes across as really very hip and a bit more brash than he is in real life."

"I guess there is a type of sexuality that goes with the job I do," says Leonard, who also guesses his appeal to women is rooted in his upbringing, overseen primarily by women --"my mother, my aunt, my grandmother, my cousin who was my age and she used to hang around with me . . .

"I mean, we gotta say the titles--'Gotta Give It Up,' you know. When we were kids, 'I Wanna Hold Your Hand' was a big thing.

"But there's a difference in being flirtatious and what you do behind closed doors," he says. "Sex of itself has really no characteristics. It's what we make of it--it can be funny; it can be sacred, sleazy. It can be a lot of things. I'm not going to tell you I'm an asexual, or indifferent, or that I don't like the company of women a lot, but I'm not into recreational sex. I'd rather have a good game of chess . . . "

Not long ago, Leonard got a letter from a handicapped girl who said her day begins and ends with his radio show. There were dried teardrops on the pages. She confessed her love for him, and no, he won't show you the letter.

"Those kind of things just make me all rejuvenated," he says.

yy y

11,.11 "We all tend to think not too terribly much about the effect we're having on the audience," says career deejay Dan Ingram, who spouted wit in the afternoon much as Leonard does--except he did it for hundreds of millions of listeners for more than 20 years on New York's WABC, the granddaddy of American pop radio.

"Every once in a while, it comes home to you," says Ingram. There was a huge traffic jam on the Long Island Expressway one day, so I said, 'While you're sitting there, might as well roll down the window and say hello to the driver next door.' Six months later I got an invitation to a wedding."