Dive computer with integrated PLB

[Dogbowl]

My husband wears a Garmin golf watch. He likes it cause it tells him how far he hit the ball. When I heard that Garmin released a dive computer with GPS, I immediately tried to interest him in it. I thought it would be an easy sell.

His first question was, "It has GPS?"

I said "Yup!"

He says, "Can it locate me if I'm lost at sea? Cause if it could, I'd buy one for sure."

I scratch my head and, not knowing the answer, went and did some research.

I tell him, "Nope, it can't locate you. It's not a personal locator beacon or PLB."

He says, "So what's the GPS for then?"

I say, "I guess it tells you how far you went during your dive."

He says, "Why would I want to know that?"

I say, kinda deflated by now, "I dunno. I guess some people wanna know!"

Then we discussed how Garmin was this big, big manufacturer with deep pockets, and how they're all into GPS technology, and how they're getting into the dive industry, and how the technology for an integrated PLB probably already exists, but just waiting for someone with deep pockets to get interested...yada yada yada...

I know how much some people love AI technology. I can see how useful it is, but for me I can use a traditional SPG and it doesn't bother me at all. I could live without AI. But, if you wanna talk about groundbreaking technology, I think a dive computer with integrated PLB would be such a technology. I mean, think about the current alternative...a stand-alone PLB in a waterproof canister - expensive, unwieldy and many people don't want to go through the hassle.

So what do you think? I'm not knowledgeable about GPS or PLB technology but do you think Garmin could do this for us?

 

[Lorenzoid]

I estimate that in a few minutes an electrical engineer with radio frequency knowledge will chime in here to further enlighten us, but it appears to me that the current PLB/EPIRB technology requires an antenna that is much longer than anything that will fit within a watch-sized device. Not to mention the power supply requirements. But like anything else electronic, perhaps it is only a matter of time.

It appears the challenges are already being worked on. For example: Patent US20090121931 - Wrist Worn Communication Device coupled with Antenna Extendable by the Arm

 

[dmaziuk]

If you get lost at sea with your cellphone within the watch's bluetooth range, and a cellphone tower within your cellphone's range, then it'll be a piece of cake. If you get lost at an actual sea, powering a signal strong enough to reach anywhere off a watch battery may not be feasible just yet. You'll have to give it a decade or three.

PS. IANAEE but I think you can get away with "only" a 6" antenna if you aim for a satellite instead of a land-based receiver.

 

[kelemvor]

The antenna size is part of it, also you'd need enough power to transmit the emergency signal. That's going to be a problem in a watch, too. Even in the other larger dive computers that have GPS integrated it would probably be a concern.

PLB's operate at 506mhz and have a wavelength of 0.73841. So with a quarter wave antenna you'd need 0.1846025meters or about 7.27 inches of antenna. Of course since it's an emergency device you could presumably use a thin wire that could be pulled out and unwound from some kind of mechanism to keep size down but I don't think that would be enough to make such a thing doable.

 

[Dogbowl]

If you get lost at sea with your cellphone within the watch's bluetooth range, and a cellphone tower within your cellphone's range, then it'll be a piece of cake. If you get lost at an actual sea, powering a signal strong enough to reach anywhere off a watch battery may not be feasible just yet. You'll have to give it a decade or three.

PS. IANAEE but I think you can get away with "only" a 6" antenna if you aim for a satellite instead of a land-based receiver.

So, does that mean that the GPS on the Garmin Descent will only work near shore?

 

[Lorenzoid]

So, does that mean that the GPS on the Garmin Descent will only work near shore?

The Garmin is a GPS receiver. No problem receiving from satellites. The difficult part is transmitting TO satellites, as in the case of a PLB.

 

[tbone1004]

The antenna size is part of it, also you'd need enough power to transmit the emergency signal. That's going to be a problem in a watch, too. Even in the other larger dive computers that have GPS integrated it would probably be a concern.

PLB's operate at 506mhz and have a wavelength of 0.73841. So with a quarter wave antenna you'd need 0.1846025meters or about 7.27 inches of antenna. Of course since it's an emergency device you could presumably use a thin wire that could be pulled out and unwound from some kind of mechanism to keep size down but I don't think that would be enough to make such a thing doable.

Top Gear had an episode with a watch with said retractable antenna. That said, adding that function into a dive computer with everything else that has to go in is probably not practical and would likely increase the cost by about the same amount as a standalone plb.

@Dogbowl no, it just is receive only, can't transmit. It should work anywhere at the surface because it's just receiving gps signals

 

[Dogbowl]

The Garmin is a GPS receiver. No problem receiving from satellites. The difficult part is transmitting TO satellites, as in the case of a PLB.

I see...it's a one-way street...

 

[Lorenzoid]

So it seems that for $16,000 or so, you can already have a watch with a PLB: Breitling Emergency - Swiss watch with personal locator beacon

Check out the Presentation link for technical details, including the manually deployed antennas.

 

[Dogbowl]

So it seems that for $16,000 or so, you can already have a watch with a PLB: Breitling Emergency - Swiss watch with personal locator beacon

Check out the Presentation link for technical details, including the manually deployed antennas.

Before I whip out my credit card, the question is: Can I take wear it diving?

All jokes aside, the technology already exists...now if Garmin can "harness" that technology, then I might see a dive computer with integrated PLB in my lifetime! (that doesn't cost 2 arms and a leg)


Apparently, Breitling sold 40,000 of the first version of this watch between 1995 and 2010, so an average of 2,667 units per year. So there is a market out there, despite its price tag. And the technology has existed since 1995. And 20 people were rescued...see this article: After Years Of FCC Red Tape, The Potentially Life-Saving Breitling Emergency II Watch Arrives In US

Here's another article with more details of the mechanics of how the antenna works: Cleared for Takeoff: The Breitling Emergency II Lands at U.S. Retailers This Summer

It is water resistant to 50m and comes with a "Diver Pro" strap or steel bracelet.