A bit of useful rescue helicopter / PLB info

[north-north-west]

The guys fly with night vision goggles. These magnify light by 6000 times.
This makes night rescue possible. When it's dark, a light source such as that of the backlight of a mobile phone, a cigarette lighter, a small fire, a head torch, whatever... All stand out as really bright hot spots on the night vision. So don't rely on the PLB, if you hear the chopper coming for you, start waving the head torch or the backlight of the mobile phone display, or whatever you have.

My ride out from near Eldon Bluff was in the dark. I was really cheesed off at missing the views, but one of the crew gave me his night vision goggles for the flight. Awesome things. I want a pair.

[tastrax]

Better save your $$$, but you will get free shipping!

https://www.nightvision.com.au/category ... n-goggles/

I was lucky enough to do the course in their use when I worked for Parks - amazing technology!

[north-north-west]

Typical you can't even get the cheap ones ($1,250) any more. But $3,800 for colour night vision . . . only 500g for the dual setup and no more need for headlamps. Think of the fun you could have walking at night.

[Robi]

Sorry to show my lack of knowledge. However, I wondering where garmin devices fit into rescues. Are spot, garmin and plb signals all treated the same way? Any recommnedations on the best source to find out?

[wildwanderer]

Sorry to show my lack of knowledge. However, I wondering where garmin devices fit into rescues. Are spot, garmin and plb signals all treated the same way? Any recommnedations on the best source to find out?

I 'think' how it works is the following

SPOT and Garmin Inreach : On Emergency activation the signal goes via satelite to a 24/7 private rescue organisation. Usually its https://www.geosresponse.com/ The private rescue org communicates with you via your device (if possible) and contacts the closest offical SAR co-ordintion agency to your postion for search and rescue.The SAR agency will activate and dispatch search and rescue services to you.

PLBs: On emergency activation the signal gets sent via satelite to an automated base station which routes it the closest offical (government) SAR co-ordintion agency to your postion. The SAR agency will activate and dispatch search and rescuse services to you

Regarding the actual radio signal.
Thats a bit more complicated.

Generally speaking a PLB sos activation signal has a higher chance of being picked up quicker as they use the global coverage COSPAS SARSAT satelite network thats has geo stationary satelites, low earth orbit satelites and now medium altitude satelites (in a higher orbit). Upon PLB activation SAR SAT satelites provide the detection/routing to rescue serices and location fixing of the PLB. The SAR SAT network is a dedicated search and rescue satelite network/system. http://www.cospas-sarsat.int/en/system- ... sat-system

Garmin uses the global coverage iridium satelite network for SOS and two way messaging. https://en.wikipedia.org/wiki/Iridium_s ... stellation
These satelites are in a low earth orbit which could mean the SOS doesnt get picked up as fast as the PLB signal as there is greater chance of a low earth orbit line of sight to your device being interupted by a mountain or the curviture of the earth (of course if a iridium sat is directly above you or in your devices line of sight then it will get picked up right away)

The other challenge is that the iridium satelites dont offer a postion service. So your garmin device also needs to be in line of sight of a postion fixing satelite such as GPS. (as far as i know they cant use the SAR SAT satelites which have dual sos and postion fixing ability). Of course even if your garmin inreach cant find a GPS satelite you can still tell the private rescue service GEOs your location via the two way messgenger service. Spot uses a similar satelite network that used to be inferior to Garmins in terms of global coverage but im not sure if thats still the case.

One major advantage of most garmin/spot vs a PLB is that you can tell if your SOS activation has been received and help is on the way. (as the private rescuse org will msg you and provide medical info and rescue eta etc). If you dont receive acknowledgment then you know to move to a postion with a better line of sight to more sky. The private rescue org GEOS can also update search and rescue services on your condition and enviroment so SAR deploy the most appropriate assets for a quick and safe rescue.

With a PLB you activate and pray that your signal is getting through. (It probably is but if your down a steep valley it might take a few hours for a SAR SAT satelite to have line of sight to you) And you dont know if help is 3 hours or 13 hours away. If for example your bitten by a snake (where moving after being bitten is bad) then not knowing if the signal has gotten through could be very stressful and cause you to make a potentialy bad decision for your health. (like climbing to the top of the hill to get a better line of sight to the sky...with your movement reducing the time it takes for the venom to reach your vital organs)

[Warin]

Sorry to show my lack of knowledge. However, I wondering where garmin devices fit into rescues. Are spot, garmin and plb signals all treated the same way? Any recommnedations on the best source to find out?

I 'think' how it works is the following

PLBs: On emergency activation the signal gets sent via satelite to an automated base station which routes it the closest offical (government) SAR co-ordintion agency to your postion. The SAR agency will activate and dispatch search and rescuse services to you

Regarding the actual radio signal.
Thats a bit more complicated.

The PLB/EPIRB system uses 2 radio signals. Both signals are transmitted at the same time.

406MHz communicates to satellites. Use is as described above.

121.5MHz is for local ground/air communication. All commercial aircraft carry detectors for this and will communicate that they have received an emergency signal and where the signal strength is strongest. Search and rescue aircraft carry detectors for this signal and can use it to get the general idea of where it is coming from (reflections from things like mountains permitting). Some remote area mines also have detection systems for this signal and their workers are equipped with PLBs for safety reasons. A few gound based searchers have detection systems for this signal too so they can get a general idea of where it is coming from.

[Robi]

Thanks all pretty useful info. I have a Garmin mini as I like the idea of being contacted and knowing my signal got through. Hopefully I will never need it, but I like solo hiking, there are plenty of snakes around and sometimes even with the best preparations things go wrong. I had heard the signal from the mini might not be picked up as easily, so was wondering if there were any situations that might justify adding the additional grams and cost of a plb.

[wildwanderer]

In most circumstances no. While the signal of a plb has a higher chance of getting through to SAR more quickly, the problem remains that you don't know if it has gotten through.

About the only environment where I would consider carrying both plb and Garmin inreach would be if I was spending the majority of the trip at the bottom of a valley that was verynarrow and featured high cliffs (as line of sight to satellites would be more restricted)

[davidmorr]

Having had to be rescued recently, I could add a couple of other notes abbot helicopters.

1. Always put out any fires. Thoroughly. The downdraft will fan the fire into a raging inferno and scatter embers far and wide. I was lucky I was upwind of the fire while the helicopter was hovering overhead or I would have had severe burns as well.

2. If you are in a forested area, the downdraft from the helicopter will have the trees swinging through angles of about 120 degrees. Some trees cannot cope with this, and branches will break off and spear to the ground. A 3 metre branch hit the ground about three metres from me. I saw others 5-10 metres long dropping a little further away. No idea what to do about this. I was not in a state where I could be moved and there were no clearings nearby anyway.

[wildwanderer]

Having had to be rescued recently, I could add a couple of other notes abbot helicopters.

1. Always put out any fires. Thoroughly. The downdraft will fan the fire into a raging inferno and scatter embers far and wide. I was lucky I was upwind of the fire while the helicopter was hovering overhead or I would have had severe burns as well.

2. If you are in a forested area, the downdraft from the helicopter will have the trees swinging through angles of about 120 degrees. Some trees cannot cope with this, and branches will break off and spear to the ground. A 3 metre branch hit the ground about three metres from me. I saw others 5-10 metres long dropping a little further away. No idea what to do about this. I was not in a state where I could be moved and there were no clearings nearby anyway.

Good info. Thanks.

Sorry to hear about your misadventure.

[GregR]

[quote="davidmorr"]Having had to be rescued recently, I could add a couple of other notes abbot helicopters.

Interested to know if you made contact via an older PLB or new fangled Spot/Garmin mini type or Phone??

How long did you have to wait?

Glad you had a happy ending.

Greg

[johnw]

If you are in a forested area, the downdraft from the helicopter will have the trees swinging through angles of about 120 degrees. Some trees cannot cope with this, and branches will break off and spear to the ground. A 3 metre branch hit the ground about three metres from me. I saw others 5-10 metres long dropping a little further away. No idea what to do about this. I was not in a state where I could be moved and there were no clearings nearby anyway.

I hope you were not badly injured and are recovering OK. I can confirm your comments about the force of helicopter rotor downwash, partly from personal experience, and that of a close acquaintance.
Some years ago a parks employee I'd known for a long time was participating in a high profile S&R operation. While they were waiting to be winched into the chopper a tree limb was dislodged by the rotor downwash. Unfortunately this person was struck by the limb which resulted in quite serious arm and shoulder injuries, taking many months to recover, with some residual damage. On another occasion I was bushwalking on the Central Coast. We descended to a popular, but less accessible, beach just as a rescue helicopter came in to land. As we passed it I spoke with some ground based paramedics at the scene, who explained that they were evacuating someone who had experienced a medical episode. He also said "We had better face away from it now" as the (large) chopper started to lift off. I quickly understood why as we were mega-blasted by sand and debris, which was more painful than I would have imagined.

[Warin]

On the PLB/AMSA side of things ...

A family of 4 in a 4WD campervan hits PLB at about 11:00am on Friday. after becoming bogged in the Simpson Desert...
AMSA said a Challenger rescue plane was dispatched from Essendon, dropping water and a satellite phone. AMSA made contact with the heavily bogged campervan about 2:30pm and confirmed there were no injuries.

So ~ 3 1/2 hours to contact. Probably includes said family getting parcel, opening parcel, reading instructions etc. Ground base rescue is being organised probably for Monday. (Comment: If they had waited to Tuesday they may well have driven out and not incurred the rescue. And why a vehicle of that weight and cost does not have a satelite phone I don't know )

[Davros]

Just a bit of information if you’re ever aware that someone is looking for you with night vision or thermal.
Military type night vision is set to magnify the Infra Red spectrum. LED torches, phone screens etc., don’t produce much. Certainly, use them! But an IR (Infra Red) strobe, an IR glow-stick, or a fire, “flaming torch” or even a cigarette lighter, will light up in night vision goggles like a supernova. Old type incandescent bulbs are really great too.
Also consider that searchers may be using thermal imaging. In which case a fire is the best way to attract attention, where safe to do so.
Conversely, if you need to avoid being seen, reducing the amount of IR and heat you put out is important. The military previously advocated red lights to preserve night vision, but some now use blue to reduce NV interception. Also, shielding heat from release can assist detection from thermal imaging.
Dave