Winter 2008 Issue

Homing In

Radio Direction Finding for Fun and Public Service

RDF Protects Lives, Provides Fun,
and Promotes Goodwill

By Joe Moell, KØOV

Sam Vigil, WA6NGH (left), with the crew chief of the helicopter team that used RDF to help find a missing Alzheimer’s patient in December. (Photo courtesy of Sam Vigil, WA6NGH)

“Thanks for all of the fun and experience that I have gotten through Amateur Radio Direction Finding (ARDF). It really paid off this week!” That’s what Sam Vigil, WA6NGH, wrote in an e-mail that I received. He was referring to the radio direction finding (RDF) skills he developed in recent years that made him a key player in finding a lost Alzheimer’s patient. When persons with dementia wander away from home, most are recovered within two miles. However, this 83-year-old victim traveled over 16 miles, but I’m getting ahead of the story.

Sam and his wife Eve, KF6NEV, were among the first to volunteer when Project Lifesaver began in their area three years ago. About 35 local citizens with Alzheimer’s disease and developmental disabilities are wearing wristband transmitters that can help searchers quickly find them if they wander away from home. Just like wildlife research radio tags, these transmitters emit 25-milliwatt pulses at about 1-second intervals on individually assigned frequencies near 215 MHz.1 Sam and others have spent many hours in training to rapidly perform RDF on these pulsed signals from the air and on foot.

RDF Rescues a Biker

The San Luis Obispo Project Lifesaver team was called into action on December 10, 2007 to find a Pismo Beach man in the first stage of Alzheimer’s disease. “He is very fit physically,” Sam wrote. “He has good long-term memory, but is deficient in the short term. His wife reported him missing when she came home from work at 5 PM.”

Sam continued, “Eve and I responded with three other direction finding teams, checking for his wristband signal on all streets for a 2-mile radius. We knew that he was on a bike, but didn’t find out until about 30 minutes into the search that his range of biking in the past has been from San Luis Obispo to Santa Maria, which is 35 miles! From past testing, we knew that the range of the transmitters is only about a mile, so we needed air support. Project Lifesaver normally utilizes California Highway Patrol (CHP) or Vandenberg Air Force Base helicopters, but Santa Barbara County came through first this time.

“Eve and I boarded at Oceano County Airport at 9 PM. The orders of Incident Commander Jon Wordsworth were for our pilot to fly south to Santa Maria and work our way back north. As soon as we crossed the Santa Maria River, I picked up a weak signal. For the next 20 minutes, we followed the biker around the north side of town as we called in the three ground teams. Just as the first team got there, we had to leave to refuel, which took about 15 minutes. When we got back over town, the signal was gone!
“As we tried to re-acquire the signal, we got a radio call that one of the ground teams was hearing it weakly to the north of Santa Maria. We headed north across the river and immediately picked it up. We were not able to see the biker, even with the Night Sun searchlight and night-vision goggles. Nevertheless, we were able to vector in the ground teams with our bearings.

“By then, the patient had reversed direction and was heading south again toward the Santa Maria River. The river is pretty dry, but we were concerned that if he went down into the riverbed, the ground teams would have great difficulty finding him safely. Fortunately, he was starting to slow down. At 10:38 PM, a ground team spotted him on a frontage road next to Highway 101. He was in good shape, with mild dehydration, and was medically released to his wife that night.”
There is no question that RDF played a vital and possibly lifesaving role in this rescue. By contrast, Sam tells of another dementia victim in his area who wandered away in 2005: “That subject was not wearing a wristband transmitter. It took three days and two nights, over 120 searchers from four counties, and three helicopters. When found, he was near death from hypothermia and dehydration.”


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