First a horse weighs, cattle more than a guitar, strumming "Get Along Little Dogies." Then the voice, light-chocolate, Milky Way tones, nassal, somewhere between tenor and light baritone:" "Howdy, partners."

It was Frank Luther, riding the range with his bockaroos across our radio bands and inviting us to "put on your somebreros, your cowboy boots, your chaps, saddle up your cow ponies and here we go, up the trail . . ."

You could almost wrap that voice around you like a coverlet. It mesmerized us.

And The Shadow, scaring the bejesus out of kids so they'd have to walk each other home in the hovering evening weirdness.

The trill of unseen terror, conjured beauty. Now those children's children, span clouds in dream-wakefulness, across celluloid space with color rayguns. Now it's Fang Face, Godzilla, Groovie Goolies careening into our Saturday consciousness.

We radio babies, glimpsing them, sigh: Our children seem not so much mesmerized as, say, glassy-eyed from all the confection. Will the Looney Tunes turn our children into loomy tuners? Ah, the innocence and color of glorious days, forever gone . . .

Well, not forever. In fact, take heart: You can still share that well-stocked reserve of imagination with your kids, and probably jog their creativity as well. Gather them and some of their friends, up to about age 13, and have a Saturday-morning radio party. It's simple and won't cost much in supplies of money, only a little of your time.

The only materials you need are a well-oiled radio, something for the kids to eat before the radio hour - hot chocolate and plain doughnuts are usually winners, or hot apple cider and croissants - and a few props, since the kids are beginners at enjoying audio and may need a little push.

There are a couple of possible themes. One might be a story party. For that, you'll need drawing paper, crayons or markers, scissors, paste and colored paper. And maybe some envelopes and stamps.

Or you could have a musical theme and have each child make or bring a simple instrument. Pie plate, spoons, comb-and-tissue are good. Drums and kazoos work well.

Next select a program, date and time. You may need to check with the stations, since there's a dearth here of programs for children, but there are a few surprise packages.

The most noteworthy is Children's Radio Theater, a monthy series broadcast Saturday mornings, usually from 9 to 10, on WPFW (89.3 PM) Pacifica radio.

The series is the brainchild of two actresses/producers/businesswomen, Doris Indyke and Joan Bellsey, who say they both love to be involved in live drama and, even more, love to play to children.

Their shows are fairy tales, science fiction and adventures done with professional actors, using original scripts or adaptations of classics. Music and songs are original too.

Currently, the stories are pre-recorded for broadcast, ussually the last Saturday of each month, but kids are invited to call in to chat with the characters, right on the radio.

"The response . . . is absolutely terrific," says Bellsey. "Sometimes we ask them to sing with us, or send us pictures of how they think we look, in character. We've even stopped the play right at a crucial time, and asked them to finish it for us. The phones just light up," she says, gesturing broadly.

"They have to imagine what's going on. They have to participate in the fantasy. That makes them stay active. Television is so passive: It does everything for you. I think kids would have a chance to enjoy their fantasies. Like with more radio."

Doris Indyke adds, "Children already have the fantastic imagination. They're primed for the action. They love the calling in, and that we invite them to write to us, and they get to be on the radio."

So far, shows have included a novel Henny Penny, a Halloween spook show and one production - "The Velveteen Rabbit," by Margery Williams - that left at least one adult, listening to a replay alone in her office, in tears. It tells of a toy rabbit who, in the very end, "becomes real" after he is ordered burned, when his little master develops scarlet fever. A two-hankie, that one.

For a Saturday party, this series is ideal.

The kids can move along with the story, making characters the way they "see" them.

In the next few weeks, right about the time the weather starts to get out of hand and the kids will be inside, there will be some excellent themes. Shows will range from one called "Let's Hear It for the Queen," with an all-teen cast, to "A Christmas Carol," "Diary of Anne Frank" and "The Witch's Tale" - the story of Hansel and Gretel as seen through the eyes of the witch. There'll also be a bilingual show (in Spanish) and one written by 11-year-olds at Gallaudet, on the experience of being deaf.

Perhaps best of all, though, is the play-writing contest running from now to December 31, for children between five and 13.

After you've listened to a good story and drawn pictures, and talked to the characters, let the group try their hand at an original script (with dialogue, if possible) or story. Make a trial run, then get them to make a neat, clean copy, and send your entry to the "Henny penny Playwriting Contest," c/o Children's Radio Theater, 1742 Kilbourne Place NW, D.C. 20010. The best five shows will be produced in the spring, and the authors invited to be in the studio for the airing.

If you're in a musical mood, classical-music station WGMS (570 AM & 103.5 FM) will begin a series called "Tropic" around mid-January. According to program director Paul Teare, the series will run for 20 weeks, tentatively at 8 a.m. Saturdays.

Lessons cover music, beginning with the basic properties - pitch, rhythm, dynamics - and moving into such themes as suites, movements and opera forms. In between there'll be about five weeks of good material for you and your group. With home-made-instruments, you can practice any number of properties mentioned in the series.

Teare says WGMS recently dropped the weekly children's story show it had been carrying because "We found ourselves repeating the same material too often. And we can't produce anything like that in-studio. It would be too expensive and, really, it doesn't fit the rest of our format."

Actually, WGMS is one of the few commercial stations to even venture into children's programming: most others are looked into strict formats that don't allow for break-away "theme" shows because of loss of revenue during commercial time. Some say, simply, that children's shows won't sell.

If you're waiting for National Public Radio, you'd better start the party without them. Program director Sam Holt says the network "hopes to put together something . . . a children's drama series, within a year. We have, in fact, just finished a series of meetings with other radio and television people involved in kids' shows, to help determine our market and their needs. There does seem to be a real vacuum there."

In January, Holt says, NPR will begin distributing "The Spider's Web," a collection of children's stories. Unfortunately, right now neither of NPR's two Washington affiliates, WAMU (88.5 FM) and WETA (90.9 FM), plans to carry the show.

For now, then, plug into one of our local offerings, skimpy though the choices are, and help the kids to some quality listering.