Liquivision Lynx and Ultrasonic Frequencies - safe for sea animals?

[Supertylie]

Hey all,

New to this forum and was looking for some insight as well as opinions on the Liquivision Lynx dive computer. I am getting back into diving after roughly a 6 year hiatus and was looking to update and purchase new dive gear, specifically a new dive computer.

After doing further research, I landed on the Liquivision Lynx dive computer and wireless transmitter which appears to be a useful dive comp for my needs and requests. While discussing this computer with a LDS, it came into discussion the ultrasonic frequencies which the Liquivison Lynx uses and how many sea animals actually rely on ultrasonics. That said, does anyone know the impact such a dive computer would have on the sea animals in your dive environment?

To indulge my interest a bit more, I called Liquivision directly to get an opinion as well as the actual frequencies that the Lynx dive computer uses. From discussing the Liquivision Lynx dive computer with their phone rep, it operates at 4 pulses per second at a frequency of 43kHz. That said, this would overlap with the frequency which dolphins, porpoises, orcas, seals, sea lions, and various fish hear and communicate. From their testing, Liquivision found no known disturbances or issues on sea life. To be diving and cause such an intrusion on ones hearing in my opinion would scare animals away or just be bothersome(imagine someone hitting a buzzer 4 times a second and there is just no way to tune it out?).

Not to sound ridiculous, but am I wrong here? I really like the concept behind this dive computer and interested in purchasing one but also have reservations with disturbing the wildlife around me as I dive.

What are your thoughts regarding this dive computer? Am I incorrect here? Any thoughts and opinions would be helpful. Thanks guys

-S

 

[Liquivision]

Hello,

Thanks for your interest in the Liquivision Lynx and thank you for your call. Just to clarify one minor detail, the frequency of pulses is every 4 seconds, not 4 pulses per second. Sorry for the miscommunication.

Cheers.

 

[tursiops]

.... a frequency of 43kHz. That said, this would overlap with the frequency which dolphins, porpoises, orcas, seals, sea lions, and various fish hear and communicate. From their testing, Liquivision found no known disturbances or issues on sea life.

I think your facts are wrong about the animals hearing ranges. Secondly, 43kHz has a very high absorption by sea water, so the propagation is not far....not to mention the power levels are quite low.

i simply would not be concerned. but nice of you to worry about it!

 

[Dr. Lecter]

43kHz has a very high absorption by sea water, so the propagation is not far

What exactly do you consider "not far" about the range of these transmitters? The whole point is that they have excellent range - for finding buddies, for reading remote gas supplies on buddies, and for navigating to a remote transmitter.

 

[tursiops]

What exactly do you consider "not far" about the range of these transmitters? The whole point is that they have excellent range - for finding buddies, for reading remote gas supplies on buddies, and for navigating to a remote transmitter.

There are two losses....sound absorbtion, and spherical/cylindrical spreading losses. The latter dominate. Even at just 100m, you can assume the source level is attenuated a factor of maybe 60 dB. I don't know the source levels. The signal processing is the key; if you match-process to the signal wave form, you can pull an astoundingly weak signal out of the noise, which is probably what they do in the Lynx. Hopefully one of their techs can come on here and tell us. Also, it would be nice to know how they concluded there were no wildlife disturbances.

There is a great site for a lot of this: DOSITS: Home.

 

[Supertylie]

Thank you for your clarification! My apologies on the erroneous posting

 

[Akimbo]

I believe bubbles would interfere a great deal more with other critters senses than this tiny transducer. And then there are the engines on the boat that are about orders of magnitude louder.

 

[tursiops]

I believe bubbles would interfere a great deal more with other critters senses than this tiny transducer. And then there are the engines on the boat that are about orders of magnitude louder.

Agreed on the bubbles. But the engine sounds are at a much lower frequency....

 

[flots am]

After doing further research, I landed on the Liquivision Lynx dive computer and wireless transmitter which appears to be a useful dive comp for my needs and requests. While discussing this computer with a LDS, it came into discussion the ultrasonic frequencies which the Liquivison Lynx uses and how many sea animals actually rely on ultrasonics. That said, does anyone know the impact such a dive computer would have on the sea animals in your dive environment?

I won't have any effect. The amount of power you can get out of a battery that size with an expected life of months or years is insignificant.

If any animals can hear it, at the most, it would be annoying or interesting.

In fact, it's so low power that the FAQ indicates that the air in your drysuit may block the signal.

flots.

 

[Akimbo]

Agreed on the bubbles. But the engine sounds are at a much lower frequency....

Actually, engine, machinery, hull, and prop noise emit a wide wide range of frequencies. A great deal is above 43kHz and a much higher intensity. Of course, the higher frequencies don't travel as far.