PLBs Can Save Your Life

[DandyDon]

The batteries sold on ebay for the Acr 2881 are third party, unapproved, with claims and warnings.

For service needed only once every 5 years, I think $116 is economical enough. My cost for the last 5½ years of carrying it everywhere, just in case, has been like 75¢ a week. The next 5 years or so will now cost 45¢ a week. I'm satisfied. Plus, if I ever have to use it in a real emergency, just return it to ACR with a good story and get a free replacement, with my story going on their site.

From: NOAA - Search and Rescue Satellite Aided Tracking - Beacon Battery Warning

Cospas-Sarsat type approval is conducted with manufacturer installed battery packs in a beacon. Therefore, NOAA recommends that beacon owners always use manufacturer approved battery packs which have been tested as a part of the original Cospas-Sarsat beacon approval and known to meet operational requirements. Beacon owners should consult their beacon manufacturer or one of their approved service centers to obtain proper battery replacements. Certain aftermarket replacement battery packs that are not approved by the beacon manufacturer have been shown to be of inferior quality and may pose a safety risk and/or result in the failure of the beacon to function properly in a distress situation.

 

[BRT]

I got a response back from Nautilus. It had a legal disclaimer about copying, retransmitting, etc. Suffice it to say that rumor has it that 34 mile range is to an antenna on a cliff while the range with diver in the water and a boat antenna only a few meters above the water is probably 10-15 miles.

I've read a couple of reviews of the device but no actual operational test. It would be easy enough to do using the position verification, vs the emergency transmission. All you'd need is a vessel with AIS to play with.

I kind of think that if Cameron had had a Nautilus the airplanes would have been watching for that signal. Range to an airplane should be fairly good. Am I wrong? Is there some reason a plane can't monitor that?

 

[JohnnyC]

So, traditionally there are certain frequencies that are always monitored. In the air world it’s usually called guard and it’s 121.5 MHz for civilian aircraft, 243 MHz for military aircraft. Maritime assets traditionally use “Channel 16,” 156.8 MHz.

Older emergency locator transmitters used a 121.5 MHz signal in order to allow direction finding equipment to triangulate its position. My original ACR unit does both 406 and 121.5, but it’s my understanding that most modern PLB’s do not dual transmit any more.

Were Cameron to have had a Nautilus Lifeline radio, he would have been able to transmit on 156.8 MHz. Whether or not an airplane would have had radios monitoring this frequency would be dependent on the capabilities of the aircraft radios. That being said, there is no reason an aircraft flying a SAR mission wouldn’t be monitoring for traffic on that frequency, although they would have to contend with all other radio traffic using channel 16.

We’re Cameron to have a PAB such as the current Nautilus offering, the device would have been transmitting on AIS frequencies, in layman’s terms sending a “man overboard” signal to anyone in range with the capability of receiving.

 

[Steelyeyes]

I kind of think that if Cameron had had a Nautilus the airplanes would have been watching for that signal. Range to an airplane should be fairly good. Am I wrong? Is there some reason a plane can't monitor that?

From what I can gather dedicated SAR aircraft have the equipment and monitor AIS. Since it's mostly a maritime system I didn't see anything about other types of aircraft being equipped to do so.

I did see that while the range ship to ship for VHF AIS signals is 45 miles it can be detected from as far up as 250 miles in space (depending on transmitter power). Capabilities to monitor ship traffic and emergency AIS transmissions via satellite appear to be getting better at a pretty rapid pace.

 

[BRT]

My point is that while we can discuss the pros and cons of all the different systems if someone is missing the searchers can watch for any of the signals and airplanes would receive low power signals at a great distance if they were line of sight. At 1000' it wouldn't take that many passes to cover a large area.

 

[DandyDon]

My point is that while we can discuss the pros and cons of all the different systems if someone is missing the searchers can watch for any of the signals and airplanes would receive low power signals at a great distance if they were line of sight. At 1000' it wouldn't take that many passes to cover a large area.

You rationalize. I'm carrying my 5 watt that hits the big system.

 

[JohnnyC]

Maybe it’s the type of diving I do that makes me particularly accepting of additional cost to manage even unlikely risk, but I have a hard time understanding why people will pay $1300 for a Perdix AI, of which for probably 90% of the divers is an entirely convenience driven purchase, but balk at spending $500 for a PLB and a canister to keep it in.

I get that we all like to have flashy, fancy, feature packed stuff, but how many people who own a dive computer that costs more than a beacon actually use all of the mixed gases and custom GF’s and constant PO2 features? How many of those people literally cannot dive without AI and a giant OLED screen?

My point is not to call out people who spend money on things that cost that much because they are full of features that the consumer will literally never use, or are a mere convenience at best, but to highlight the fact that we can quite easily justify significant purchases like a Shearwater, yet make excuses about why we avoid purchasing something that could literally save a life one day. “Buy insurance” is one of the most recommended courses of action on this site, so why are we not recommending this type of insurance as vocally?

 

[letterboy]

Maybe it’s the type of diving I do that makes me particularly accepting of additional cost to manage even unlikely risk, but I have a hard time understanding why people will pay $1300 for a Perdix AI, of which for probably 90% of the divers is an entirely convenience driven purchase, but balk at spending $500 for a PLB and a canister to keep it in.

I get that we all like to have flashy, fancy, feature packed stuff, but how many people who own a dive computer that costs more than a beacon actually use all of the mixed gases and custom GF’s and constant PO2 features? How many of those people literally cannot dive without AI and a giant OLED screen?

My point is not to call out people who spend money on things that cost that much because they are full of features that the consumer will literally never use, or are a mere convenience at best, but to highlight the fact that we can quite easily justify significant purchases like a Shearwater, yet make excuses about why we avoid purchasing something that could literally save a life one day. “Buy insurance” is one of the most recommended courses of action on this site, so why are we not recommending this type of insurance as vocally?

Spot. On.

I have two Zeagle n2itions that I use. Nothing fancy, but it does what it needs to do. Would it be sweet to have one of the touchscreen air integrated computers? Maybe, but I could buy 4 n2itions (or more) for the price of one of them there fancy touchscreen color computers.

 

[seeker242]

Older emergency locator transmitters used a 121.5 MHz signal in order to allow direction finding equipment to triangulate its position. My original ACR unit does both 406 and 121.5, but it’s my understanding that most modern PLB’s do not dual transmit any more.

Near all PLBs still transmit on 121 MHz, but that is secondary to 406 MHz. It's intended for short range direction finding, when SAR is already in the general area looking for you.

 

[GameChanger]

I bought my Perdix AI for it's 2-button simplicity and ease of reading the display (Sucks getting old...). There was/is nothing wrong with my 2 yr old Oceanic OC1 watch style dive computer. I Just found the menu functions a tad difficult and the display was getting harder to read (for me).

I am applying the same logic to my pending PLB/canister purchase. I want something simple to use yet reliable.
JMHO/YMMV