ACR EPIRB vs Resqlink PLB

[requiem]

Originally Posted by JustCroozin

121.5 MHz is used by aircraft and RDF equipment. The 406 MHz EPIRB signal and associated GPS coordinates are what we rely on to find you.

I had always thought the 406 signal was a burst transmission and not practical for homing, but a week or so ago I ran across the story here (page 25) that suggests homing is now done on the 406 MHz signal. Are you also able to use that, or just relying on the relayed coordinates or doppler location?

[IslandHopper]

Originally Posted by requiem

I had always thought the 406 signal was a burst transmission and not practical for homing, but a week or so ago I ran across the story here (page 25) that suggests homing is now done on the 406 MHz signal. Are you also able to use that, or just relying on the relayed coordinates or doppler location?

I think most SAR units carry equipment capable of homing in on 406 MHz these days, certainly are down here in Aus/NZ and for sure in the US......

EDIT: Old DF-430 https://www.rockwellcollins.com/~/me...a%20sheet.aspx

New DF-500 https://www.rockwellcollins.com/Prod...on-finder.aspx https://www.rockwellcollins.com/-/me...20190117211050

[Username25]

Ocean Signal rescueME PLB1 + Ocean Signal rescueME MOB1(AIS)

Both fits well into life jackets (always on mode). With 2x PLBs on board, signal will be up for 48 hours. PLB is a great last resource in MOB situations. I bet with sat phone onboard coastguard should be able to provide MOB coordinates via PLB in case range of MOB1(AIS) out-of coverage and coastguard chopper is hours away.

[Wotname]

Originally Posted by liferaft

Major differences:
PLB designed to operate for 24 hours at -20, EPIRB is 48 hours at -20

Note, that is -20 C, which about -4 F

PLB has to be switched on manually. EPIRB has a water activated switch (disarmed when in its bracket) so it will start when put in the drink. It can also be manually activated.

Note, not all EPRIBs are water activated, it depends on the category.

PLB will NOT float with its antenna out of the water. Most require an extra buoyant pouch to float adequately but that does not address the antenna. EPIRB is designed to float with the antenna out of the water.

I am now retired but used to sell and service these devices.

Posted in the interests of clarity, not disagreement .

[Wotname]

Originally Posted by requiem

I had always thought the 406 signal was a burst transmission and not practical for homing, but a week or so ago I ran across the story here (page 25) that suggests homing is now done on the 406 MHz signal. Are you also able to use that, or just relying on the relayed coordinates or doppler location?

Ahh... the advances of technology. Yes, some modern homing devices can home very very well on the 406 burst transmissions and due to the much stronger radiated power, the lock on range can be up to 90 or so miles.

Some pilots I know still prefer to use the analogue 121.5 signal when at close range especially as the homing is not as dynamic when using the digital 406 (as the busts are 50 t o 60 seconds apart).

They also decode the 406 transmissions so the beacon identifier (and any embedded GPS co-ordinates) are available to the flight SAR crew.

FWIW, these homing receivers are quite broad banded and can be tuned to a variety frequencies including VHF ch 16.

[a64pilot]

Originally Posted by requiem

I had always thought the 406 signal was a burst transmission and not practical for homing, but a week or so ago I ran across the story here (page 25) that suggests homing is now done on the 406 MHz signal. Are you also able to use that, or just relying on the relayed coordinates or doppler location?

I haven’t article, but your correct the 121.5 signal would be for homing, the 406 is a data burst, and nearly impossible to home on.
Homing takes time, that is why the USCG and others will ask you for a long count and likely several if they are trying to DF your VHF.

However the satellites using I guess Doppler can triangulate a 40t signal, this is not DF or “homing” but they can get a rough idea as to location and I believe after several succeeding passes they can reduce the circle of error.

[Wotname]

Originally Posted by IslandHopper

I think most SAR units carry equipment capable of homing in on 406 MHz these days, certainly are down here in Aus/NZ and for sure in the US......

EDIT: Old DF-430 https://www.rockwellcollins.com/~/me...a%20sheet.aspx

New DF-500 https://www.rockwellcollins.com/Prod...on-finder.aspx https://www.rockwellcollins.com/-/me...20190117211050

Yes this true for airborne SAR in Aus. The Rockwell Collins kit with it's software defined receiver is pretty nice and works very well, way better than earlier generations of discrete analogue receivers - I have installed quite a few different generations of homing devices over the years and if I was sitting in a life raft waiting for help, I know I would be hoping the cavalry had the current technology on board!!!!!!

[Wotname]

Originally Posted by a64pilot

I haven’t article, but your correct the 121.5 signal would be for homing, the 406 is a data burst, and nearly impossible to home on.
Homing takes time, that is why the USCG and others will ask you for a long count and likely several if they are trying to DF your VHF.
.........

This was true back in the day of discreet receivers but fast forward to software defined receivers and computer aided technology and it becomes "easy".

I found it hard to believe when I installed my first 406 homer but they work very well - at least for getting within the last mile or so. In poor visibility (or mountainous terrain) some pilots do revert back to 121.5 as posted above.

[a64pilot]

Well, I guess I’m showing my age, the data burst we sent with Longbow if you were listening to the freq. you would sometimes hear a click, that was it.
I was told it couldn’t be DF’d, but then I Retired from that job 18 years ago.

[Quadrille in JB]

Lots of good discussion on EPIRBs and PLB.
I sat down tonight to order a ACR ResQlink and I found that there's several models, all fairly close in price. I'll only be sailing between FLa and the Bahamas for the next few years so; Which one should I buy?
I have already ordered the ACE buoyant carrying pouch for one.
thanks in advance for your advice.
Bill in JB

[RUSTYNAIL]

EPIRBs meet a different standard than 406 MHz PLBs. Electronically they work the same, but as mentioned before the PLB has a smaller battery. The PLB on its own won't float with the antenna out of the water. That's not a small factor. EPIRBs are designed to float straight up so the antenna can transmit to the satellites. EPIRBs also have a strong strobe light that helps the pilots find you at night. In an emergency situation, that may be the difference between life or death. The float free Cat 1 model is an additional important factor. Most USCG aircraft have the ability to home in on the strong 406 MHz burst. Some aircraft can even receive the gps position on the 406 transmission. Every little bit helps speed up the rescue. If you have an old 406 EPIRB or PLB without gps, get a new one. You might save a couple hours of launch time for the command center. They can't launch until they have a good position, and the new 406 beacons take very little time to lock on to the gps position. You can find a lot of articles about my research on the internet. I carry an EPIRB and PLBs.

[requiem]

Originally Posted by Quadrille in JB

I sat down tonight to order a ACR ResQlink and I found that there's several models, all fairly close in price.

I'm not in marketing but I feel like having a confusing variety of similar products would hurt sales, and ACR's website seems to have been infected by the current trend of content-free design.

As best I can make out, the Aqualink models may have longer battery life and slightly more transmit power. The models with "view" in the name may be able to display your coordinates and are possibly designed to be compatible with a future rollout of "return link" messaging (i.e. you can get a message saying in effect "We got your signal and are coming to help.") Some of them may float, others might not.

Personally I'd get an EPIRB if there's a boat involved, and supplement it with an MOB1 (if you sail with crew and have the electronics onboard) or a PLB1 as backup. I have less experience than most others here, but I suspect that should you need to use one, having to hold a PLB upright in your hand is going to get in the way of attending to other things that might also be important (e.g. bailing).

[IslandHopper]

From the ACR website......

[CarlF]

As others have mentioned, once you are swimming it doesn't really matter if your PLB sinks or you hold it wrong. Your chances of surviving hyperthermia the 4-6 hours until rescue arrives is vanishingly small. Fortunately, almost all EPIRB activations are from the boat or from a liferaft.

In a liferaft, the PLB doesn't need to be held upright. The antenna just has to be out of the water.

You don't need a 48 hour battery because SAR knows your location in about 20 minutes. If the signal continues for a couple of hours, they've also plotted your drift and will keep that plot going without more signals. Unless you are in the 1% who sail in high latitudes or the most remote areas, a plane or chopper will reach you within 12 hours

I believe anyone considering a EPIRB or PLB should also consider an InReach. In most situations, an InReach will get you rescued more quickly and more effectively than an EPIRB or PLB.

This is because over 95% of EPIRB and PLB signals are false alarms. Rescue efforts are delayed by hours while SAR tries to contact the people in the database. The two-way communication of the InReach usually allows immediate confirmation - as well as critical information for SAR such as number of people, nature of distress, and injuries.

That said, any piece of technology can fail - be it an InReach or an EPIRB. That's why I carry an EPIRB as a backup to the InReach.

[Pizzazz]

It is a little bit disconcerting and expensive that marine safety devices are so specialized. EPIRB, PLB, etc. The InReach is an all purpose device, you can text, communicate, broadcast your position and receive confirmation in case of distress. You can send an email to your boat with your position if you fall overboard. It is a great device. I would feel much more comfortable being in touch with friends of family updating them on a potential emergency vs. the on/off nature of a distress beacon. Focus on the benefits not if it is part of GMDSS.

That being said, if you are in are crewing/racing you will be forced by the captain to get an AIS beacon.

If you are sailing solo, it really depends on your tolerance to risk. You can carry a life raft, multiple beacons, SSB, etc. and still not make it or you can get lucky. I carry an Inreach on me and SSB on the boat plus whatever the racing rules require. Some people are more safety conscious.