MUCH OF today's bad television might be considerably more enjoyable if it were worse. Gone are such ghastly subterranean delights as Joe Pyne, the Amateur Hour and "You Asked for It" -- fascinating oddities that could be sources for rich amusement and derision. Now trash-seekers are left with little more than an occasional satin-suited evangelist and between-match interviews on the wrestling and roller derby shows. "The Gong Show" doesn't count -- it's awful on purpose.

Now and then, however, a staunchly raunchy TV movie approaches the state of reverse perfection -- perfect terribleness. NBC has been specializing in the form this season, never with more mawkishly lurid success than in "Aspen," a boiling-pot of Fun Pulp that was totally accessible because there wasn't a soul in the world who didn't feel superior to it. And wasn't correct.

Tonight and for two more nights running, NBC challenges the depths plumbed by "Aspen" with "Loose Change," the TV-novel version of Sara Davidson's bestseller about three girl friends of the '60s and how they grew up and apart. NBC plays literal havoc with the book, abandoning it to bounce from bedroom to protest demonstration and back to the bedroom again -- all that's lacking is a protest demonstration staged in a bedroom. This is producer-director Jules Irving's and a pack of feckless writers' idea of relevant drama, with plenty of lip-smacking sexual innuendo for audience appeal. Part of the fun of watching it is that every predictable act of calculation can be spotted easily.

Topical details, to give us a sense of the times and their passions, are dropped in with thundering thuds. The three key women -- whose names have even been changed from the book, though it was presented as fiction -- and the peripheral and generally loathsome men in their lives wander through the issues and events of several eras like mechanical Dorothys on a yellow brick road through Berkeley, Birmingham, Chicago (1968), Vietnam, Haight-Ashbury and you-name-it.

The consistency is not so much foolish as foolproof; almost never is there a hint of authenticity, whether the scene is a Doodletown Pipers version of an SDS meeting (where the fresh-faced rebels suddenly leap up to cheer "What do we want? Freedom! When do we want it? Now!") or the home of some latter-day activists circa '68, where wife Kate advises husband Joe to cool it with those hot answers to a nosy reporter's questions.

"Joe, that's not good propaganda," she says.

"Some radical you turned out to be!" counters Joe. "Look at this place -- you don't even keep it clean!"

It soon becomes evident that if "Change" were to suddenly burst into realism, it would stop being a treat. The original plan of the producers was to punctuate the film with authenticating newsreels; almost all traces of this are out, and just as well.

The first half hour gives an indication of where we are headed. It is allegedly set at Berkeley during the first stirrings of '60s political unrest, and one perky little politico has a red-spotted fish she's named "Karl Marx" swimming around in her aquarium. It is pointed out that there are "25,000 students" enrolled at the university, only a short time after a young woman is warned that if she chooses to live with a boy without benefit of matrimony, "Everybody on campus will be talking about it." All 25,000 of them?

"What is truth?" that wild and crazy kind of a poetry teacher John Campbell (played by the unsavory John Getz) asks his class, promptly dropping his pants to illustrate a point about D. H. Lawrence. Later he deflowers a student named Tanya (played by Season Hubley and called "Tasha" in the book) at the seashore by reciting his Bohemian verse at her: "Spring crows, a dizzy black above my head, et the seeds of love. . ."

Novelist Davidson saw the TV version of her book and found it disappointing but not heartbreaking. She'd been hoping to sell the book to the movies but that didn't come through. "Then television comes along and says, 'We'll take it and here's a lot of money.' I haven't given up the hope, though, that someday somebody will make a decent movie out of it," she says from Los Angeles.

Davidson actually finds much about the TV version to admire, including the actresses who play the three lead roles -- especially Christian Raines as Kate Evans. "What I had hoped," Davidson says, "is that it would be at a slightly more elevated level than the average television program." But production was rushed, so much so that Pocket Books had to race to meet the air date with the paperback version of the novel, which originally wasn't supposed to appear until May. It's now being hawked in the hope the TV production will boost sales.

"They did a very fast job; they did it in a rush. But I didn't see any evil at work," Davidson says. She doesn't care how "faithful" the film is or isn't to her book, but she says she's sorry that entire themes got dropped -- like the importance of the women's movement to her characters, and to women and men, and the "whole element of celebration that went with the hippie movement in the '60s, the whole communal feeling that happened when thousands of people got together and became instant friends, family even, who shared the same values, thoughts and goals. Later, that proved illusory, but at the time it was exhilarating."

People who were offended by such docu-dramas as "King" will not be by this, because fidelity to reality isn't feigned. "Loose Change" could even be considered a success. "King" aimed high and missed; "Change" aims low and scores a bulls-eye.

There are pleasures to be had in squalid bilge, traditionally from sleazy movies like "Valley of the Dolls" and "The Carpetbaggers." But now not even the makers of such movies seem to have the true trash knack; audiences flocking to "The Betsy" surely must be disappointed with its stately to deadly whispered tone, even though the picture's origin is a merrily steamy novel.

"Loose Change" is more fun than "The Betsy" -- though its sex scenes are not nearly so explicit, of course --partly because it is riper, less pretentious and more unashamed.

But it could have been much, much better; it could have been a contender, something more than a six-hour time-killer with sex scenes scattered around to keep folks interested. It could have been more than a camp pageant that uses its "turbulent '60s" setting the way Grace Metallious used that little town called Peyton Place.

"I hung around the set for a few days," Davidson recalls. "They would ask me what I thought and I would tell them. They would shake their heads 'yes' -- and then do exactly what they wanted.

"But they were all very nice," she says.