Personal Locator Beacons
Join Date: Mar 2007
Location: australia
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The specs for your GPS acquisition times are pretty much as per this guide
So I wouldn't be to concerned. Any gps requires a small amount of time to start up
http://www.gme.net.au/public/pdf/bro...lb_epirb_b.pdf
The cospas system doesnt allow for the immediate transmission of position data anyway to ensure a GPS has found its real location - so there will also be a few minutes of delay anyway.
The beacon will transmit its unique code from the first transmission though so your registration details will be transmitted - it won't wait till it gets your gps position - so you don't need to get your money back
So I wouldn't be to concerned. Any gps requires a small amount of time to start up
http://www.gme.net.au/public/pdf/bro...lb_epirb_b.pdf
The cospas system doesnt allow for the immediate transmission of position data anyway to ensure a GPS has found its real location - so there will also be a few minutes of delay anyway.
The beacon will transmit its unique code from the first transmission though so your registration details will be transmitted - it won't wait till it gets your gps position - so you don't need to get your money back
Last edited by onemore; 31st Dec 2012 at 02:18.
Join Date: Jul 2006
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For any of the SAR boys out there ......
Which is the best signal / homing device you prefer to "see" to be assured of rescuing several and possibly widely spread passengers in the sea in poor visibilty if all were carrying any of these devices?
SAR T, 121.5 homer, 406?, strobe, streamer, smoke ......
How does person in water (not life-raft) ensure good signal - attach to life-vest / head, or floating device?
Which is the best signal / homing device you prefer to "see" to be assured of rescuing several and possibly widely spread passengers in the sea in poor visibilty if all were carrying any of these devices?
SAR T, 121.5 homer, 406?, strobe, streamer, smoke ......
How does person in water (not life-raft) ensure good signal - attach to life-vest / head, or floating device?
Join Date: Feb 2007
Location: Darwin, Australia
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I'd say this Australian made PLBs selected by AMSA is management's answer.
Last edited by werbil; 22nd Jan 2013 at 22:18.
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In my SAR experience, going back a little ways, obviously the best thing is an EPIRB/PLB. From an operator perspective type doesn't really matter - RCC will provide a lat/long from the GPS or triangulation, then the rescue aircraft will home on the 121.5. But following that, a heliograph (signalling mirror) is your best friend. Not so good in poor weather, admittedly, but it can't break, it's waterproof, it doesn't need batteries and I've personally spotted them at something like 12nm and heard of people seeing them from much further than that.
In poor weather, flares and bright clothing are your best bet. As for beacon placement, I'm sorry but I don't know; however in the water my understanding is it's not crucial. Different story on land - spent quite a long time trying to home to a beacon in remote NT - we ended up finding the persons in distress from their heliograph in the end. The EPIRB was on the floor of their aluminium dinghy and between a little terrain masking and that, it made DFing it hard work.
In poor weather, flares and bright clothing are your best bet. As for beacon placement, I'm sorry but I don't know; however in the water my understanding is it's not crucial. Different story on land - spent quite a long time trying to home to a beacon in remote NT - we ended up finding the persons in distress from their heliograph in the end. The EPIRB was on the floor of their aluminium dinghy and between a little terrain masking and that, it made DFing it hard work.
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Homing is helpful but the key difference between GPS/Non GPS is time. Crudely minutes to hours.
Initial 406 transmission is (instant) mostly picked up first time id'd and AUSSAR hit the phones. By the time this procedure is followed the GPS has locked on and they have a position (3 sec lat, long say 130m) within a few minutes. Without GPS they will get the 5nm doppler position in hopefully within 3 hours.
Initial 406 transmission is (instant) mostly picked up first time id'd and AUSSAR hit the phones. By the time this procedure is followed the GPS has locked on and they have a position (3 sec lat, long say 130m) within a few minutes. Without GPS they will get the 5nm doppler position in hopefully within 3 hours.
A beacon in the water should ideally float UPRIGHT.
Most PLBs/ELTs float, but any which way, generally on their sides. The homing signal from a beacon in this position can be severely attenuated, I have sat over the top of beacons in these positions and they have been nearly impossible to home to with something less than a 5nm range signal and heavily lobed at that. Throw in any sort of sea state to regularly block out what signal there is and you can be working very hard to home those last few hundred meters, a head in the water is a dismally small target regardless of how good the Lat/Long initially supplied is. (which is usually excellent)
An EPIRB (marine) is best if you think an in water scenario is likely, they float upright and boom out a great homing signal.
Next best would probably any beacon attached to life jacket so the antenna is out of the water, guys that mess around with RC boats would know how important this is.
The question about multiple targets in the water is a good one. Lots of beacons in the water can create a sonic blancmange, it's a scenario I know has been mulled over by offshore energy companies and there is good knowledge in AMSA on potential/existing technologies, it is well worth asking them.
My personal summation would be, for an in water scenario, rescue is improbable without a beacon, too small a target, far too much water.
With a beacon, regardless of type, location is highly likely. Do the rescuers a favour by having your antenna out of the water as best you can, sea dye works very well in a moderate sea state, smoke markers are quite short range and generally very short lived, mirrors are great if you know how to use them.
Most PLBs/ELTs float, but any which way, generally on their sides. The homing signal from a beacon in this position can be severely attenuated, I have sat over the top of beacons in these positions and they have been nearly impossible to home to with something less than a 5nm range signal and heavily lobed at that. Throw in any sort of sea state to regularly block out what signal there is and you can be working very hard to home those last few hundred meters, a head in the water is a dismally small target regardless of how good the Lat/Long initially supplied is. (which is usually excellent)
An EPIRB (marine) is best if you think an in water scenario is likely, they float upright and boom out a great homing signal.
Next best would probably any beacon attached to life jacket so the antenna is out of the water, guys that mess around with RC boats would know how important this is.
The question about multiple targets in the water is a good one. Lots of beacons in the water can create a sonic blancmange, it's a scenario I know has been mulled over by offshore energy companies and there is good knowledge in AMSA on potential/existing technologies, it is well worth asking them.
My personal summation would be, for an in water scenario, rescue is improbable without a beacon, too small a target, far too much water.
With a beacon, regardless of type, location is highly likely. Do the rescuers a favour by having your antenna out of the water as best you can, sea dye works very well in a moderate sea state, smoke markers are quite short range and generally very short lived, mirrors are great if you know how to use them.
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I did some research of the options a couple of years ago and bought the GME unit with a GPS.
Can't really comment if it's good or bad because I've never had to use it.
It is very small and light so I can just carry it in my nav bag. It seems to meet all of the requirements and is not very expensive. I'd recommend it.
Can't really comment if it's good or bad because I've never had to use it.
It is very small and light so I can just carry it in my nav bag. It seems to meet all of the requirements and is not very expensive. I'd recommend it.
