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Electronics

Lifeguards in the Sky Page 2

Electronics — January 2004
By Ben Ellison

Lifeguards in the Sky
Part 2: “Despite some current limitations, SARSAT will really save your keister when needed.”
   
 
 More of this Feature
• Part 1: SARSAT
• Part 2: SARSAT
• Show Time!
• McMurdo Pains Wessex
• BeaconSure
• Sea Marshall US
• Northstar

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If you do go EPIRB shopping, you’re going to find a lot of choices. For one thing, as of last July, Personal Location Beacons (PLBs) were approved for use in the United States. These portable units are capable of a full 406/121.5 transmissions (see writeup on McMurdo Fastfind, opposite page) and can be carried on land adventures like hiking and backcountry skiing where calamities can have that same awful two-stage nature. Regular EPIRBs designed specifically for boats have twice the battery life (48 hours), float upright, and are equipped with a strobe and, in Category I models, automatically activate when they hit the water. However, Daniel Karlson of NOAA’s SARSAT center says his agency doesn’t mind that some boaters will opt for the flexibility and affordability of PLBs, noting that in the situations when SARSAT is meant to be used, i.e. when self-rescue or other communications like VHF are futile, a PLB is way better than nothing.

Then there’s the GPS business, and this is where the going gets sticky. Back in 1998 SARSAT was modified so that a lat/lon position could be encoded into the 406-MHz distress signal, meaning that rescue centers could get your nearly exact position within a few minutes instead of the 30 to 90 minutes for a rough position typical of the Doppler technique. Manufacturers like ACR and McMurdo Pains Wessex began producing EPIRBs and even PLBs that either interfaced with a GPS or had one built in. It sounds like a “must have” option, but it’s also a technically tricky proposition. GPS signals are notoriously weak, and an EPIRB with one inside, often dubbed a GPIRB, has to do a cold start while possibly in rough water and definitely in close proximity to RF transmissions. The alternative of firing up a dedicated GPS, getting position, and then activating the attached EPIRB or PLB may not be practicable, especially when the poop hits the fan.

In the course of researching this column, I discovered that the Coast Guard and NOAA, concerned about the low number of successful GPS-assisted SARSAT calls, did some real-world testing off Key West, Florida, last year. I’ve read the report, and it’s disturbing. Some models seemed to deliver GPS position poorly, if at all. But the report is also brand confidential and controversial. Only ACR, proud of the apparent high performance of models like the GlobalFix (pictured on opposite page), has identified its own coded test units; other manufacturers say that the whole test procedure was flawed. I’ve also spoken with experts who say that EPIRB and PLB certification standards are weak, and hence we need to worry about claimed battery lives and transmit powers. Ugh! I am not happy to report this possible messiness in what I believe is an amazing safety system, but I can add some good news.

The Equipped to Survive Foundation is planning on launching a better-designed program (with more public testing), which will be sponsored in part by West Marine and the BoatUS Foundation that may have taken place by the time this issue prints. Everyone involved is hopeful that the Key West results turn out to have been an anomaly, but whatever the outcome, I’ll at least summarize the results in this column when they’re available.

For now I’ll close with the words of NOAA’s Karlson: “Despite some current limitations, SARSAT will really save your keister when needed.” However, this tool has a lot of responsibilities that come along with it.” So true! Shop carefully for an EPIRB or PLB, register it properly, and keep the contact information current (both now possible online at www.sarsat.noaa.gov). Then learn how to test it, how to use it most effectively—like giving it a good sky view—and how to avoid false alarms (and what to do if you don’t avoid them). Chances are good that you’ll never need it, but...

Next page > Show Time! > Page 1, 2, 3, 4, 5, 6, 7

This article originally appeared in the December 2003 issue of Power & Motoryacht magazine.

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