TIMBERLINE LODGE, Ore. (AP) _ An electronic signal system to find lost climbers was unveiled Monday and dedicated to nine people who died on Mount Hood two years ago.

Two young climbers who survived the state's worst mountaineering disaster attended the ceremony. The frustrating search for survivors led to an effort to develop and pay for the tiny signal devices to be worn by climbers.

''Every now and then it unfortunately takes a tragedy to make us aware of needs that always existed,'' U.S. Sen. Bob Packwood, R-Ore., said at the ceremony.

Seven teen-agers and two faculty members from the Oregon Episcopal School in Portland died in May 1986 after getting lost in a blizzard near the summit of the 11,235-foot peek about 50 miles east of Portland. Four climbers survived.

The U.S. Forest Service estimates more than 10,000 people climb Mount Hood each year. Since 1896, more than 50 people have died on the mountain.

The signal system, called the Mount Hood Locator Unit, consists of a small, 8-ounce transmitter that is worn on a harness over the climber's torso. When the climber is lost, he or she pulls a cord to activate a continuous beep over a VHF radio frequency.

When the climber is reported overdue, search and rescue groups can use special receivers to pick up the beep, which grows louder the closer the receiver gets to the transmitter.

The battery-powered transmitter will send the signal at least 20 miles and can be picked up under 6 feet of snow and as deep as 75 feet in an open crevasse.

Brinton Clark, now 17, made her first public statement since the tragedy and thanked those who took part in the search two years ago. ''Your dedication is the reason I'm here today,'' she said.

Giles Thompson, now 18, of Longview, Wash., lost both legs to frostbite and was interrupted by applause when he announced he planned to go skiing.

''And I wouldn't be going skiing if it wasn't for the efforts of a lot of people,'' he added.

A hundred transmitters will be available for climbers to rent for a maximum of $5 at any of six mountaineering shops in the Portland area, said Scott Russell, co-chairman of the Mountain Signal Memorial Fund. Use of the device is not mandatory.

The device was developed by Telonics Inc. of Phoenix, Ariz. Although similar devices have been used to track wildlife, companies had not adapted one for human use because of the potential liability if the device should fail.

Organizers of the signal fund convinced the Oregon Legislature to pass a liability exemption last year.