[HN Gopher] Device offers long-distance, low-power underwater co...
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Device offers long-distance, low-power underwater communication
Author : marban
Score : 44 points
Date : 2023-09-06 16:56 UTC (3 hours ago)
(HTM) web link (news.mit.edu)
(TXT) w3m dump (news.mit.edu)
| mikewarot wrote:
| This sounds like an acoustic analog of the radio tracking device
| that was disclosed by Snowden a decade ago involving a quarter
| wave antenna that was selectively grounded. It was trackable at
| 20 miles, and totally passive.
|
| It could run for months on a single coin cell battery.
| beebeepka wrote:
| I guess I was so enthralled with the rest, that I have missed
| this device. If it's totally passive, what's the battery for?
| myself248 wrote:
| Observing the parameter being monitored and deciding whether
| to ground or not ground the resonant element.
|
| "Passive" in this case meaning that none of the battery power
| was turned into RF. It did not produce any RF. It merely
| absorbed more or less RF to encode information.
| backendanon wrote:
| As a former Submariner and Sonar Technician (trained in
| oceanography and underwater acoustics), it's interesting that
| such low power could be used. Long range underwater transmission
| of sound isn't a new thing. It's possible to passively track
| targets for up to 3000 nautical miles when the audio gets trapped
| in the deep sound channel.
|
| The device discussed in the article has only achieved a distance
| of 300 meters using a slightly modernized version of sonar
| transducers and receivers that have been around for a very long
| time. I've seen MIT ocean projects meet the real world and go
| poof, but it's good to see people are out there trying to figure
| things out again, in the world after the pandemic.
| soperj wrote:
| I'm guessing this will really be hell for whales.
| [deleted]
| Gys wrote:
| [flagged]
| RalfWausE wrote:
| [flagged]
| ck2 wrote:
| Can they use this to stop killing whales when they try to talk to
| military subs halfway around the world?
|
| (the current method is like a person standing next to a jet plane
| taking off to underwater life)
| chrisBob wrote:
| It might work at distances longer than 300m, but "they ran out of
| space on the dock." That seems like such a silly limitation to
| bring up twice in the writeup.
| RobotToaster wrote:
| Sounds like a passive aggressive way of saying "tight ass
| funders didn't give us enough money to test this shit properly"
| jgeada wrote:
| It's an MIT press release. Technique probably doesn't work at
| any interesting distance, but this way they can make it sound
| as if they've discovered something incredible without ever
| having to acknowledge that they know it won't work as
| described.
| hinkley wrote:
| Wow.
|
| If it's "long distance" put the unwieldy piece where you have
| reserved space and move the less complex piece to borrowed
| space. Like another jetty, or a beach, or here's a crazy idea:
| on a seaworthy vessel. You know, to test your marine
| communications device on a marine vehicle?
| dylan604 wrote:
| My natural first reaction is what unknown effect will this have
| on underwater life? We know other types of sonar have had
| negative effects. Knowing that, this should be studied and
| considered when making any new underwater sounding equipment. You
| don't get to go "we never thought about it" now that _we_ know
| about it.
| backendanon wrote:
| At 1 million times less power than existing sound transmission
| systems I'd say it's probably less audio going into the water
| than a baby whale fart.
| awei wrote:
| This was also my first thought.
| EricMausler wrote:
| This is cool. I'm not sure if I missed it, but did they address
| how a signal is generated by the array in the first place?
|
| My current understanding is that the device will echo a signal
| back to the source, not propagate it forward or create a signal.
|
| Is it right to assume low power sensors exist and would be hooked
| up to this array, and then when the sensor triggers the array
| echos the signal to the other receiver?
| IshKebab wrote:
| I'm pretty sure only one side of the communication system is
| "battery free". The other side is a standard phased array.
| Mountain_Skies wrote:
| Wonder how well it would work for things like RC submarines. The
| distance increase isn't all that valuable for RC but the lower
| power required sounds very useful.
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(page generated 2023-09-06 20:00 UTC)