LURAY, Va. - If a GPS unit talks in the woods, will anybody hear it?

Not my family, apparently. On a recent hike down to Dark Hollow Falls in Shenandoah National Park, I poked haplessly at the gadget slung around my neck, trying to watch a video on the small screen, while my mother and my boyfriend loped along ahead of my father and me on the trail. My father, meanwhile, was half-listening to the chipper female voice coming from the device, but mostly he was checking out the scenery, not the screen.

My family and I were at the park for our annual Father's Day getaway, and I roped them into trying out GPS Rangers, which the park introduced last summer. Each paperback-size Global Positioning System device, created by a company named BarZ Adventures, contains recorded tours of four popular hikes: to the top of Hawksbill Mountain, down a hill to Dark Hollow Falls, along a one-mile portion of the Appalachian Trail, and on a ramble through Big Meadows.

They were all hikes I'd been on before, most of them with the park's human rangers, whose frankness, humor, and expertise make guided hikes the highlight of every trip.

So I'll admit it: I was biased when I rented my first GPS Ranger at the Harry F. Byrd Sr. Visitor Center, across from Big Meadows. Could these gadgets truly replace or match the experience of a ranger walk?

"Our product complements, it doesn't replace, the rangers," says Lee Little, who designed the GPS Rangers and runs BarZ Adventures.

Little conceived the idea after traveling around Europe and Asia and U.S. national parks.

"I was amazed by how little information was available to tourists to answer questions like, 'What am I looking at?' " he says. Other common questions: "Where are the bathrooms?" and "Where can I get a Coca-Cola and a T-shirt?"

"There is a place for technology" in the parks, Little says. "A one-to-one relationship is always preferred, but it's not always possible."

GPS Rangers fill in gaps in park rangers' busy schedules, since the devices are available all day. One snag is that the battery lasts only three to four hours. (We had one that conked out after two, unfortunately.)

Another hitch is the cost: Ranger walks are free, but you have to shell out $9.95 for a GPS Ranger. And where a real ranger can project his or her voice to a big crowd, the mechanical version is better suited to smaller groups or individuals.

The technology, though, is cutting-edge. As you walk along a trail, your location cues videos on the roughly 4-by-2-inch screen through a GPS antenna on the back of the device, which gets signals from orbiting satellites. The videos, which feature park rangers, historical photos, and music, correspond to sites along a trail - a pile of rocks where a house used to be, for example - and the on-screen maps tell you how far you are from the next stop and the next video. (That's as the crow flies, though, so if the trail is winding, the distances won't be exact.)

When you miss a point, you can manually play the videos from anywhere in the park. That ended up being helpful, because we missed points on all three walks, probably because we didn't follow directions and watch the whole introduction. (See "Escape Keys" for tips on getting the most out of your electronic guide.)

Our first GPS Ranger outing was the Meadows Mysteries tour, which features 17 points scattered throughout the 137-acre Big Meadows. There's information about the camp where members of the Depression-era Civilian Conservation Corps lived, the soldiers who trained there for World War II, and the Weakley family, who had to leave their land when the park was established in 1935.

Some of the natural history points were interesting, too, and pertinent - we listened to facts about the meadow's marshy area as our shoes sank into the mud. My father pointed out, though, that some meadow features, such as the wildflowers, are seasonal, which the programmed message can't address as thoroughly as a ranger could.

The GPS Rangers are better suited to more linear trails than to the meadow. The Appalachian Trail tour includes history about the trail and stories from people who hiked it. And it mentions the people who lived nearby, including the Weakleys, the Corbins, and the Nicholsons, which is fitting, because the tour ends at a well-tended cemetery where some of them are buried.

The Dark Hollow Falls tour is all about water, from the trickle in the stream near the trailhead to the gushing waterfall at the bottom. The Hawksbill tour covers the park's geological history, plus the peregrine falcons that nest atop the mountain.

More often than not, we ended up just listening to the narration as we walked, eschewing the screen for old-fashioned scenery-gazing. It's not the kind of ranger walk I'm used to, but it's a novel way to learn about Shenandoah - a high-tech guide to the park's low-tech charms.

Taking a Walk in Shenandoah National Park

Shenandoah National Park, 75 miles southwest of Washington, D.C., has more than 500 miles of trails, including 101 miles of the Appalachian Trail. Many trails are accessed from Skyline Drive. Some short trails lead to a waterfall or viewpoint; longer and more difficult trails penetrate deep into the forest and wilderness.

More than 300 of the park's structures are listed in the National Register of Historic Places, ranging from Big Meadows and Massanutten lodges to bridges, stone-lined ditches, and log comfort stations.

Admission to the park is $15 per car, good for seven days. There's a fee-free weekend scheduled for Aug. 15-16.

Places to stay

Lodging in the park ranges from campsites ($20 a night) to full-service cabins ($259 for summer weekend nights). Make reservations at www.visitshenandoah.com/lodging-food/index.cfm or by calling 1-888-896-3833.

Places to eat

The Big Meadows Wayside restaurant near the Byrd Visitor Center has comfort food such as fried chicken ($8.95 for a two-piece meal) and hot dogs ($6.95), plus fancier fare including the Antipasto Vegetable Wrap ($7.95). For a post-hike pick-me-up, a scoop of blackberry ice cream ($1.75) or a milkshake ($3.50) can't be beat. The Skyland and Big Meadows lodges also have more formal, full-service dining rooms with a variety of options (dinner entrees, $13 to $30).

GPS Rangers

Rent a unit from the Byrd Visitor Center, which is open daily, 8:30 a.m. to

6 p.m. You must return the units that day, so plan accordingly. Units are $9.95 apiece and have about 31/2 hours of battery life.

Tips on the devices

Watch the introduction and tutorial. It takes a few minutes to access a strong GPS signal, so don't try to start the tour right away.

Have the antenna up.

Use the "hold" button to save battery power when you're not on the trail.

More information

Shenandoah National Park

540-999-3500, www.nps.gov/shen

- Christina Talcott

SOURCE: National Park Service