Personal locator beacon

[ShinyShoe]

Originally Posted by HDAV

So there can be a delay but this is likely at polar regions not covered by geo orbits. Populated areas likely will be.

Low orbits like you say are the only cover in the poles. But for 99.999% of use here - not an issue we have stationary cover. BUT Low orbits also help when no GPS signal is obtained. Getting a GPS fix on a moving device in the water is not as perfect as you might imagine. If you think getting a fix on an iphone in a moving car is sometimes sluggish... its far worse with no cell tower to help narrow down where you are, an alamanc that is 6 years old and so useless and needs re-downloaded and a receiver that is wobbling in the water. While I'd never buy a PLB without GPS (don't think they are still made anyway) - I think it is usefully re-assuring that a LeoSat can get a fix on you!

However despite all this airlines with far more sophiscated SARSAT kit are lost. PLB are great but not infallible and not a vhf replacement in my opinion carrying a PLB, VHF and flares on your person is the best option if you are solo on the water.

What makes you think an airline has more sophisticated SARSAT kit? For some reason that I fail to fully understand they usually just have a transponder that transmits on 121. No float free EPIRB.

The Malaysian Airline that is still missing didn't have an EPIRB. All the satellite modelling that has been done is from data from its engines that it sent back to Rolls Royce every few minutes.

It should have also had the airline equivalent of AIS. But it was 'switched off' (or failed) part way into the flight.

If you had AIS on your boat, and CG have access to satellite AIS - there would be logic to an EPIRB not really needing to give a position - just identify the boat and locate it on sat AIS... that is the airline theory... unless your AIS mysteriously switched off...

Still not a fan of the personal flare, although I may regret that if I am in the sea one day!

[gpsguru]

Originally Posted by ShinyShoe

BUT its not quite as simple as seeing 3 birds. The shouldalways be possible at sea in UK waters. But the GPS will need to download its almanac as it won't have been "on" recently enough to have one. The alamanac is played on a loop from the sat over 12.5minutes, so in theory you can get a first fix on a completely "cold" start in 12.5 minutes. Provided a wave didn't wobble your PLB position and mean it lost a bit of data. I'm not a GPS expert but I think if there are 3 sats - then in theory the GPS may be able to share the download out so you don't need to wait 12.5 minutes for missed bits to re-appear and might get a first fix in ~4 mins if uninterupted. But that would require the 3 sats to be issueing perfectly co-ordinated messages...

A lot of PLB 66Ch GPS receivers do NOT require the alamanac, even your modern car satnav does not require the alamanac by using 'quick fix'.

...........I actually checked this with Ocean Rescue and they kindly when through the whole process with me from the point of activation, including the timings and embedded hexdata assembly............. I was in the Satellite business before I retired in 2012 .........

[MustRib]

Just going back to the original post, my humble opinion is get the best safety
kit you can afford, make sure anything that is "personal" is securely attached
and carry some redundancy in your methods of raising the alarm.
A PLB would be a must, a handheld VHF, mobile phone in a waterproof bag, pencil flares, laser flare
...if you are in trouble you would be wishing you had the lot believe me.

Shiny Shoe makes a lot of valid points in his post,
and I would guess his timings are probably pretty accurate.
Information and events are still managed at Rescue Control Centres by human beings,
and sometimes things are not so easy for them to interpret.
Despite everything that has been posted so far on this thread,
if your reading this trying to decide whether or not you should
buy a PLB if you don't own one, it is a fantastic piece of technology for the money.
Buy one.
Maybe I am overestimating the boating disposable income of people reading the forum posts,
but I would guess that if you own a boat, you can afford a PLB and a Handheld VHF,
so buy both if you don't have them already.
If you can - I suggest handling as many PLB's as you can before purchasing.
Ask in the chandlery to pick one up and hold it.
If you end up in the water, you may be holding that beacon in your hand for a couple of hours, in the cold.
Smaller may not necessarily be the way to go.

Satellite location technology is more advanced now than that currently
available to the boating community.
With the MEOSAR sats coming online, and advances in beacon design and technology,
the return signal from the beacon is a reality, and the system will no longer be inert.
With that comes remote activation of Beacons, the ability to remotely turn a beacon off and on to conserve battery life,
and to turn on a beacon to locate an overdue vessel or aircraft.
For the manufacturer this technology has to be standardised to receive
approval for civilian use and that compliance isn't as straightforward as one
would imagine. France, the USA, Canada and Russia are the major influential
founder countries behind COPSAS SARSAT.
France and the US had been pushing for different signal modulation - "widespread spectrum"- a wide band
signal,
Canada and Russia wanted to stick with the existing narrow band signal.
Recently all countries agreed to use the widespread spectrum with MEOSAR,
which gives much more bandwidth to send more information.
Currently beacon transmissions are limited to a 60 bit length identifier,
and sending more than that is not possible with the LEOSAR and GEOSAR systems.
MEOSAR allows a larger identifier, more bandwidth , more information.
Government and military entities must adopt the widespread spectrum,
for manufacturers to have a chance of cascading that new technology down to the public.
Existing beacons will still be supported by the Sat System,
don't wait to buy a PLB if your thinking about it - its a small amount of money
for a lot of punch.

[jonp]

We have to carry an epirb by law on any vessel venturing more than 2nm offshore. Plb's don't meet the same requirements for us boating even though you can carry them onboard additionaly. Plb's are considered more a safety precaution for land wilderness exploring.

Epirb's float in the upright position and have far longer lasting batteries.Beacon types and models - Beacons

[MustRib]

Originally Posted by jonp

We have to carry an epirb by law on any vessel venturing more than 2nm offshore. Plb's don't meet the same requirements for us boating even though you can carry them onboard additionaly. Plb's are considered more a safety precaution for land wilderness exploring.

Epirb's float in the upright position and have far longer lasting batteries.Beacon types and models - Beacons

worth noting for all the Australian readership on the forum, but to be clear for the
UK leisure boaters reading this, there is no mandatory requirement for an EPIRB.
The RYA do have some guidance on it all
https://www.rya.org.uk/knowledge-adv...b-and-plb.aspx

[gpsguru]

Originally Posted by MustRib

Just going back to the original post, my humble opinion is get the best safety
kit you can afford, make sure anything that is "personal" is securely attached
and carry some redundancy in your methods of raising the alarm.
A PLB would be a must, a handheld VHF, mobile phone in a waterproof bag, pencil flares, laser flare
...if you are in trouble you would be wishing you had the lot believe me.

Shiny Shoe makes a lot of valid points in his post,
and I would guess his timings are probably pretty accurate.
Information and events are still managed at Rescue Control Centres by human beings,
and sometimes things are not so easy for them to interpret.
Despite everything that has been posted so far on this thread,
if your reading this trying to decide whether or not you should
buy a PLB if you don't own one, it is a fantastic piece of technology for the money.
Buy one.
Maybe I am overestimating the boating disposable income of people reading the forum posts,
but I would guess that if you own a boat, you can afford a PLB and a Handheld VHF,
so buy both if you don't have them already.
If you can - I suggest handling as many PLB's as you can before purchasing.
Ask in the chandlery to pick one up and hold it.
If you end up in the water, you may be holding that beacon in your hand for a couple of hours, in the cold.
Smaller may not necessarily be the way to go.

Satellite location technology is more advanced now than that currently
available to the boating community.
With the MEOSAR sats coming online, and advances in beacon design and technology,
the return signal from the beacon is a reality, and the system will no longer be inert.
With that comes remote activation of Beacons, the ability to remotely turn a beacon off and on to conserve battery life,
and to turn on a beacon to locate an overdue vessel or aircraft.
For the manufacturer this technology has to be standardised to receive
approval for civilian use and that compliance isn't as straightforward as one
would imagine. France, the USA, Canada and Russia are the major influential
founder countries behind COPSAS SARSAT.
France and the US had been pushing for different signal modulation - "widespread spectrum"- a wide band
signal,
Canada and Russia wanted to stick with the existing narrow band signal.
Recently all countries agreed to use the widespread spectrum with MEOSAR,
which gives much more bandwidth to send more information.
Currently beacon transmissions are limited to a 60 bit length identifier,
and sending more than that is not possible with the LEOSAR and GEOSAR systems.
MEOSAR allows a larger identifier, more bandwidth , more information.
Government and military entities must adopt the widespread spectrum,
for manufacturers to have a chance of cascading that new technology down to the public.
Existing beacons will still be supported by the Sat System,
don't wait to buy a PLB if your thinking about it - its a small amount of money
for a lot of punch.

A top post from a man that has used a PLB for its intended purpose


I didnt mention MEOsar / MEOsat as I thought it might confuse the issue, but yes, 'spread spectrum' technology is here now and very successful in other applications, so I guess it will just be a matter of time.


PLB's have dropped in price over the last few years, so it is a relatively small investment.


When I accidently set mine off the response was 15 - 20 mins, both by phone and being called on 16 by both voice and DSC .............. the reason it went off was due to a broken safety switch flap ...... whoops