New York — ''The cutting edge of television evening news'' marks its first anniversary Sept. 5. That's what executive producer Lester M. Crystal calls America's only nationwide hour of evening news, ''The MacNeil/Lehrer NewsHour'' (PBS, weekdays, check local listings, since times vary). Already nominated for Emmy Awards for its coverage of events in Lebanon and Grenada, ''NewsHour'' has created a tasty if heavy format that consists of a highly nutritious blend of interviews, discussions, documentaries, essays, profiles, book reviews, and now, talking political cartoons.
If it has a major weakness, it is in spot news: ''NewsHour'' simply does not have the broad range of correspondents at the ready to pop onto the screen with coverage of every major regional event. So it covers them with a verbal summary, often accompanied by graphics.
Although most of the on-screen participants on ''NewsHour'' are capable news people, the fact is that none of them have developed the kind of electronic charisma that keeps some viewers coming back. And there is a kind of deadly seriousness to all the goings-on, as if the heaviness of world events rests a bit too heavily on the shoulders of ''NewsHour.'' Viewers who have given up on the show seem to recognize that it is sometimes a bit like spinach, good for you but a bit boring if you indulge too often.
Perhaps the talking political cartoons (a dramatized review of cartoonists' work) will add a smile to the too-often sour visage of ''NewsHour.''
Robert (Robin) MacNeil and Jim Lehrer co-anchor the program from New York and Washington, with Judy Woodruff, Charlayne Hunter-Gault, Kwame Holman, Elizabeth Brackett, and Charles Krause functioning as correspondents.
Production units from more than 30 public-television stations contributed material to ''NewsHour'' this year, and there are plans to use them even more in the future. ''They have helped us accomplish greater diversity and national scope,'' Les Crystal explained at a recent breakfast interview at the Park Lane Hotel, only a few blocks from the New York headquarters of WNET, which co-produces the series with WETA, Washington.
Mr. Crystal, who previously spent 20 years with NBC News, does not believe the commercial networks will be able to expand their evening news to a full hour. ''They are locked into the half hour because local stations are never going to give up their own half hour. I think the only chance for an expansion of news coverage to an hour on networks lies in the prime-time magazine format - if they develop in a way that would permit them to go on a daily basis.''
According to Mr. Crystal, the biggest problem facing ''NewsHour'' is scheduling. ''There are some PBS stations around the country which air us early in the evening. It would be much better later, when more people are home with more time to watch. Ideal time would be 8 p.m., and there are a couple of stations running it around that time and doing quite well.'' For PBS, quite well means a 9 or 10 percent share of the sets in use, which is less than half of what most network news shows attract.
Does Crystal regard ''NewsHour'' as a supplement to network news or as an alternative?
''Of course, there are those who look at it as a supplement. Especially in areas where we air after the network evening news or, as in New York, at the same time. Many people tune in to us for the second half hour. But those who watch us from the start have begun to understand that they will be getting all the major news. The most significant difference is that we take major stories and spend as much time on them as is called for - sometimes as much as 20 minutes. So, while we report spot sories, too, we don't feel we have to cover all of them, which gives us enough time to expand on the bigger stories. Our viewers come away with a lot better sense of what it's all about.''
Although the viewership of ''NewsHour's'' first half hour is sometimes smaller than the viewership of the old ''MacNeil/Lehrer'' half-hour report, that for the second half hour now tops the total for the old show. According to Mr. Crystal, there is around a 13 percent overall increase. Does he consider that a success?
''When I look back at the major stories of the year, I believe we proved our capability of reporting what is happening and staying on top of the major stories of the year, giving them analysis and doing more than one story per night. We've been able to cover three or four times the number of stories the old report could cover. On those days, if you didn't have a 22-minute story, you just didn't do it. Now we do stories of any length.
''But in the coming year, the measure of success will be our ability to continue to do that and at the same time to add diversity in the way of special features, some overseas bureaus, an increase in arts coverage, and a larger audience. I would say my idea of success for next year would be a gradual, steady growth as we continue to achieve our editorial objectives.''
The underwriter of the series is AT&T. Has it interfered with program content?
''Absolutely not,'' Crystal says. ''No editorial interference at all. But they have been extremely supportive in terms of promotion and advertising.''
Will new technology be affecting TV news in the near future?
''Teletext and videotext are specialized and limited. Unless news is part of your life style or business, the majority of viewers will be more casual in the way they get news. But with the expansion of the use of VCRs (videocassette recorders), you can't tell how viewing habits will be shaped in the future. I foresee the day soon when the VCR will be part of the standard TV set.''
So Crystal believes that basically television news is alive and well?
''Fairly alive and well. But it needs to come to grips with the need to go beyond headline service. With the networks getting more influence through more stations than they ever had, it's a great challenge to see if they can break out of where they are. They simply cannot stay the same.
''Within the time constraints of network news, they can give the public what's happened but very little of the hows and whys - and they are most important. 'NewsHour' always manages to find time for the hows and the whys. Network news must do more of that sooner or later.''
Both John Chancellor of NBC and Daniel Schorr of CNN credit the influence of ''NewsHour'' to a tendency to try to do longer, more comprehensive pieces on their networks.
Lawrence Grossman, NBC News president, who headed PBS when ''NewsHour'' was inaugurated on PBS, admits: ''Many of our own correspondents watch or tape it. They use it for background in developing their own stories.''
What's next for veteran newsman Les Crystal?
''I've been lucky, in that my jobs in TV news have allowed me to do a lot of stimulating things. But this has been the most stimulating and satisfying job ever, and I intend to stay with it.
''I go home every night pleased that our show has covered stories well and that we have all made a contribution to understanding. People who watch are actually saying, 'I never really knew that before.'
''And that makes me feel good.''