Here they are again, those amiable a.m. lunatics of the local ether, those darlings of the Board of Trade, those indispensable sources of endless data about closed schools and blocked freeways. Yes, here they are, Jackson Weaver and Frank Harden. Having another anniversary.

Twenty years, and locally they're right up there with Pat and Mike, Shake and Schlomozzle, Gilbert and Sullivan, Rogers and Hammerstein and peanut butter and jelly. Not (discreetly) to mention Mutt and Jeff.

They are a lot more, too, although it's a little difficult to figure out just what . . .

It is 5 a.m. in the Kennedy Center. Mary and Joseph Sandoval from Arlington are sitting in the first of half a dozen rows of folding chairs in the Grand Foyer facing the lobby of the Opera House. They are waiting for Harden and Weaver. The gala 20th anniversary celebration for WMAL's undisputed champions of early-morning radio is still half an hour from its start.

"Oh," says 66-year-old Mary Sandoval, "we're just as crazy as they are.

"You know what they did to me once?" she recalls. "We heard -- this was years ago -- they were at the Statler so my daughter and I just decided to go down. Joe had gone to work. So we went down and they said to me, 'Do you want to say anything?' and I said, 'Well, can I say hello to my husband? And I said, 'Good morning, Joseph.' He heard it in the car. And then one of them said, 'I bet it's the first time she said good morning to him in years.'"

That's the kind of thing they do all the time. They're low-key funny. We've been very careful not to step on toes," Jackson Weaver was saying Wednesday in the pint-sized studio the pair share at WMAL's Jenifer Street, NW headquarters. Switching back and forth with practiced ease from on-air prattle to a sandwiched-in interview, H and W allowed that "we feel when people get up in the morning it's rough enough. As it is, you're tired, draggin', and you don't want to start any unwanted adrenalin flowing . . . If you take a firm stand on anything, the first thing is you've alienated a whole bunch of people, and we're not in the alienation business. We're in the friend-making business.

Several thousand of those friends -- Park Service officials were'nt sure exactly how many -- took advantage of the much-vaunted free Kennedy Center parking and free coffee and doughnuts to share the 20-year celebration yesterday morning.

But free was not the operative word. They'd have come no matter what.

The way it was supposed to work at the Kennedy Center was that people would come and go. Trouble was, though, almost everybody came, but almost nobody went.

Must have been a bit of tardiness around town yesterday.

There were supposed to have been more big names at the broadcast from the Grand Foyer, but (excuses, excuses) Sugar Ray didn't get back in town, and Pearl Bailey had, would you believe, finals . . .

Then there was poor Father Gilbert Hartke, Catholic University's -- and the city's -- dramatic guru-emeritus, as it were. Father Hartke managed to make the show yesterday, all right, but he'd have had more on-air time if the show had been Thursday, because the good father showed up then, too. At 5 a.m.

"The security men saw this man in a long black coat with a white collar and," he said. "Well, you know there's supposed to be a ghost in this theater . . .

"I walked through the whole building from the basement to the atrium looking for the show . . . and then I was blocked in. I got out at 6:25.Still wondering what happened to you guys . . . ."

"Well, think of this way," soothed Jackson Weaver. "It was a great dress rehearsal."

People just love them. Like Dollie Johnson. Mrs. Johnson is 83. She and her son-in-law Frank Hand arrived at about 5:15 and didn't leave until almost 10:30. "They're just great," she enthused. "You know, I was a grade mother in elementary school with Bill Mayhugh's mother."

Bill Mayhugh was there to wish well to Frank and Jack. His WMAL-radio stint directly precedes the H and W show. So were WMAL's Felix Grant, Ed Meyer, Bud Steel, Tom Gauger, Bill Trumbull and Chris Core (the late afternoon boys, waiting in the wings, maybe?).

And there was 22-month-old Rodney Harrell Jr. Well, actually Rodney came to see his mom. Donna Harrell, the H and W sound engineer, is almost as popular with the fans as the stars themselves.

Some statistics from Frank Forrester, Park Service meteorologist: In 20 years Frank Harden and Jackson Weaver have spoken 159,273,000 words. And used up 16,973,000 cubic feet of air.

Some even less reliable statistics provided, in this case, by comedian Mark Russell: "In 20 years they've done 46,520 time checks, 43 of which were correct, 104,328 weather reports, 92 of which were grossly optimistic. They've played 42 records . . ." "No," interrupted Weaver, "only 12."

"And," continued Russell, "142,000 commercials."

"All this," he jibed, "from WMAL on Jenifer Street, NW, heart of the inner city . . . no moving to the suburbs for this station . . . although 20 more feet . . ."

Anytime you're driving along in the morning rush and you see somebody in a nearby car laughing uproariously, Harden and Weaver are probably on the car radio.

Everybody's got a favorite Frank and Jack story. Ardent listener Bob Armstrong recalled how he almost cracked up his car on this one:

Roy Rogers, so Harden and Weaver recounted (as though, recalls Armstrong, "it was real news") received a pair of new boots from Dale Evans. aHe was out riding, got hot and went swimming in a creek. A couger came along and ate up the boots. Roy shot the cougar and took it home, whereupon Dale asked, "parden me, Roy, is that the cat that chewed your new shoes?"

An incomplete listing of the gifts that were showered on the pair include: Two dozen multicolored balloons. Two green bountonnieres. Plaques and certificates of honor beyond count from the likes of county executives Charles W. Gilchrist (Montgomery), Lawrence J. Hogan (Prince Georges) and John F. Herrity (Fairfax). A proclamation sent by Gov. Harry Hughes, and a videotape of the entire show courtesy of the Capital Centre's Abe Pollin.

Also there were four big cakes in assorted shapes, including two small rabbit-shaped cakes and another in the form of an old-fashioned radio with a reclining statue of a nude (Woman) carved out of chocolate on the back. w

Statues of Smokey the Bear from Smokey, whose voice is actually Jackson Weaver's.

A window from Charles Kettler, the builder. The studio doesn't have one, and Kettler thought it was about time H and W stopped saying it was sunny when everybody else could see it was pouring cats and dogs.

And from a local bank came a song. A dispatchee of Eastern Onion arrived on the scene and delivered a paean to H and W to the tune of "76 Trombones" and followed that with a commercial jungle for the Citizens Bank of Maryland.

The program featured three live bands: a combined armed services band, a blues band and "the big band sound" from the four-piece Sammy Farrell group, referred to by Mark Russell as "geriatric punk rockers."

There were four marches instead of the usual one, and were they loud. Also a sensational performance by the University of Maryland choir of Sibelius' Finlandia, as the daily hymn.

Frank Perdue. Laughter. He was really there, the super chicken man himself. Everybody cheered. Did Jackson Weaver really ask him to "show us your numbered parts?"

Well Frank Harden did ask him what he does with feathers. Did you know they use them for the foam they spread on runways when a plane is in trouble?

Never mind that the parts are really tagged, not numbered, there were all the usual references to unsightly hair, legs and breasts. And in a final, dazzling display of noncommunication, Frank Perdue's appearance was followed by a commercial: for Holly Farms.

Jackson Weaver, who is 59, has actually been at WMAL for 37 years, and Frank Harden, 57, has been around for 33. They were staff announcers, and nobody -- them included -- thought their morning show would take.

Now WMAL worries that somebody else will take them, although they've already turned down one bid network bid. Salaries in the ballpark of $150,000, along with their genuine love of Washington, somewhat temper the charms of other pastures.

They are big business. In '78-'79 surveys, they were found to have an average daily audience of 99,200 adults. Some 406,000 people listened at least once. Commercials on their show cost $365 a minute. And advertisers have to wait in line to get one.

At every break in the Kennedy Center broadcast, H and W were mobbed by fans reminiscing, seeking autographs and lavishing gifts, some of them home-made or hand-drawn.

"Sometimes it's embarrassing," Frank Harden had said on Wednesday. "This outpouring of affection."

"You know," said Weaver, "It's not like a rock star. It's more practical than that. We're with these people every morning -- in bed with them (snicker), in their bathrooms, in their cars. It's an intimate situation. We're part of their family . . .

"But our attitude is that we're like a utility. You get up in the morning and you turn on the light, you want light to show. You turn on the coffee pot and you want the damn coffee to start perking, and when you turn on the radio you want to hear Harden and Weaver. They don't want any excuses . . . and they complain when we take a vacation . . . A utility."

Sure, fellas, but when was the last time Pepco got kissed?