The PLB’s digital signal can broadcast more data than the old analog signal, including information identifying the sender and, if equipped, Global Positioning System (GPS) coordinates locating the signal source to within 100 yards. The low-orbiting satellites also can find the sender by homing in on the strongest signal, narrowing the search area down to three square miles.
That position is transmitted to a ground station in Maryland. From there, phone numbers registered to that PLB user are automatically dialed. If the person doesn’t answer, staff at the Maryland station contact the appropriate rescue agencies.
What the FCC ruling did was to allow the PLBs to use the higher frequency already used by emergency position-indicating radio beacons, or EPIRBs. The old PLB frequency was cluttered with airline chatter and signals generated by apparatus such as pizza ovens and electronic scoreboards, resulting in hundreds of false emergency alerts every day, Carlson said.
The new frequency has been averaging just a dozen alerts per day and operators can quickly determine the veracity of a rescue call by simply dialing the phone numbers associated with the distinctive serial number embedded in the rescue signal.
Carlson said the biggest concern is that encouraging outdoorsmen and mariners to carry PLBs could open the door to many more false distress calls.
But in Alaska, with its vast tracts of inhospitable wilderness and dangerous seas, the PLB has been in use at the higher frequency since 1994. False alarms just haven’t happened. In 2001, 54 lives were saved using PLBs in Alaska, with only one false distress recorded.
Unlike maydays broadcast over radio, PLBs let rescuers know who has issued the call for help, thanks to each unit’s unique identifying signal. Lack of anonymity has helped deter false reporting.
“For the outdoor market, this is a whole new device. They haven’t seen anything like this before,” said Chris Wahler, director of marketing for ACR Electronics in Fort Lauderdale, Fla., a manufacturer of PLBs.
There are now around 100,000 emergency beacons using the higher frequency, 90 percent of them EPIRBs on ships. Around 400 PLBs are being used in the United States, but Wahler expects the new FCC ruling will increase demand. Carlson said NOAA is prepared to handle another 100,000 or more PLBs.
Right now, prices are high, at between $600 and $1,000 or more per unit, but Wahler said volume could rise to match EPIRBs’, and that would bring down prices.
Search and rescues are also expensive. According to the Coast Guard Search and Rescue Web site, it costs $3,700 per hour to run aircraft, $1,550 per hour for a medium-size ship and $300 to $400 per hour for a small rescue craft.
“Usually the people we’re looking for are in the water. Trying to find a head half the size of a basketball is truly a needle in a haystack,” said Smith, the Chatham harbor master.
He was impressed by the potential of the PLB and had a realistic take on the expense.
“I would think every crew member would want to have one,” he said. “It’s expensive, but it’s somebody’s life.”
Copyright, 2003, Cape Cod Times. All Rights Reserved.