CACHE-AS-CATCH-CAN HIGH-TECH SCAVENGER HUNT RAPIDLY GAINING POPULARITY.

Byline: Bill Becher Special to the Daily News

Everyone loves a treasure hunt, and now there's a high-tech version called geocaching that can combine satellite navigation, code breaking and plain old hiking.

Geocaching, pronounced ``geo-cashing,'' is a rapidly growing world-wide sport that uses Global Positioning System (GPS) receivers to locate stashes hidden by others. The hiders post latitude and longitude coordinates on the geocaching.com Web site, along with difficulty ratings, hints and other information.

Once you've found a cache, you can declare your find at geocaching.com. Most caches contain a logbook you can sign and inexpensive trinkets you can exchange. Many caches have themes such as the ``Snake Pit'' cache at Point Mugu State Park, which contains rubber snakes.

Most caches are outdoors, for the simple reason that GPS receivers don't work indoors.

But not all caches are in the wild. Some have been located at shopping malls, such as the ``Mall Rat'' cache at the Northridge Mall. ``Virtual'' caches exist at places where you can't hide something, such as at national parks or public monuments. You ``find'' the virtual cache by going to the site and answering questions about it. There are even underwater caches that require scuba gear to find.

Another variation is the ``travel bug'' - a sort of movable cache. Cachers find the bug, take it some place and post the location at geocaching.com for others to find and take on another trip. Some bugs have traveled around the world this way.

The GPS system uses signals broadcast from satellites launched by the U.S. Department of Defense that are translated into latitude and longitude coordinates by GPS receivers.

Geocaching got a big boost in 2000 when President Clinton directed the Department of Defense to stop scrambling the civilian version of the signals. Previously, its accuracy had deliberately been degraded to avoid aiding military foes. After the change, even a $100 consumer GPS receiver can get you to within 20 to 30 feet of a cache. A land-based supplemental signal called ``WAAS'' will further improve accuracy in some areas.

Except for buying a GPS receiver, the sport is free.

Carolyn Greene of Newbury Park, who's found more than 250 caches, and Steve Hall of Simi Valley are geocaching enthusiasts. Like birders' life lists, geocachers talk about the total number of caches they've found. Both also like to hide caches for others to find.

On a recent five-hour jaunt in Point Mugu State Park with friends Wolf and Ingrid Schmidt, who they met geocaching, Green and Hall located four caches. Green disappeared from the group for a while to hide the ``La Jolla Valley Jewel Cache,'' which contained costume jewelry.

They started at home by entering the zip code for the area they're going to at geocaching.com. This produced a list of the closest sites, which are assigned two ratings: one for the complexity in finding the cache and the other for the difficulty of the terrain where it's located.

Coordinates for the sites can be manually entered into a GPS receiver and stored as ``way points'' or downloaded into the receiver using special software. Links to online maps of the site locations are also shown at geocaching.com.

Most geocachers do some homework before they go into the field: obtaining good topographic maps of the area where they're going and figuring the closest trailhead or access point. Others download satellite photos of the area where the cache is located.

Some caches take months to find and involve intricate puzzle solving or code-breaking to locate, including one that uses a computer emulation of the World War II German ``Enigma'' code machine.

There are some limits to caching. National Parks are off limits to even ``micro caches'' the size of a 35mm film canister. This rule is from the same government that favors opening the Los Padres National Forest and the Arctic National Wildlife Refuge to oil drilling.

The Deseret News in Salt Lake City reported that a cache in an ammo can was investigated and removed by the police bomb squad.

Common sense should dictate where caches are placed say cachers. The Sierra Club suggests avoiding placing them in a bear's den.

CACHING IN

--Geocaching.com is the ``official'' Web site for geocaching. You only need to register (for free) to make use of most of the features. An explanation of geocaching terms and techniques is included.

--A basic GPS receiver that can display coordinates to three decimal places will get you started. Popular brands are Magellan and Garmin, especially the Garmin eTrex series. Some have built-in compasses, others allow downloading and displaying maps.

--GPS Made Easy: Using Global Positioning Systems in the Outdoors by Lawrence Letham is a good guide to using a GPS receiver.

--Be sure to prepare for a geocaching expedition the same way you would a hike: carry a compass, plenty of water, appropriate clothing and a map, and let someone know where you are going and when you will be back. Check the logs at geocaching.com before you leave to make sure the cache is still there. If you take something from the cache, replace it with another similar item.

A guide to some local caches:

--La Jolla Valley Jewel Cache at Point Mugu State Park. GPS coordinates: N 34(cpyrt) 06.319 W 119(cpyrt) 02.224 (WGS84). Difficulty rating: 2.5, Terrain: 3.

La Jolla means ``jewel'' in Spanish and this cache contains jewelry box items. The cache is on the ground, hidden at the base of a coyote bush. Suggested access is from the La Jolla Valley Trail from the Pacific Coast Highway.

--Quarter Cache. GPS Coordinates: N 34(cpyrt) 12.307 W 118(cpyrt) 51.057 (WGS84). Difficulty: 2. Terrain: 1.

This small cache east of the 23 Freeway contains only state quarters. Please bring a state quarter if you take one.

--Cloud City in the Santa Monica Mountains. GPS coordinates: N 34(cpyrt) 06.006 W 118(cpyrt) 38.916 (WGS84). Difficulty: 2.5. Terrain: 3.5.

The hider said, ``It may not be cloud city when you find it ... but on the day we hid the cache it was like we were floating in a misty cloud city.'' Approach from the Red Rock Canyon parking lot or off Stunt Road. You are looking for a clear plastic container with a blue lid.

--Cheeseheads on Dirt Mulholland. GPS coordinates: N 34(cpyrt) 07.631 W 118(cpyrt) 31.331 (WGS84). Difficulty: 1.5. Terrain: 1.5.

This cache is located in San Vicente Mountain Park in a fairly good-sized plastic container.

CAPTION(S):

2 photos, box

Photo:

(1 -- 2) Steve Hall, front, of Simi Valley and Carolyn Green of Newbury Park are avid geocachers. Green has found more than 250 caches since taking up the world-wide sport. Geocaching uses Global Positioning System (GPS) receivers to locate stashes hidden by others, such as the one above, found by Hall at Point Mugu State Park.

Bill Becher/Special to the Daily News

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CACHING IN (see text)