Winter 2008 Issue
Radio Direction Finding for Fun and Public Service
Protects Lives, Provides Fun,
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.
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!
“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
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