Hi, Looking for suggestions on low power, underwater data communications in fresh water. Range can be as low as 14 meters. I understand that most underwater communications use ultrasound, but one reason is slat water conductivity. Maximum amount of data is approximately 20 bytes at a time.
Thank you.

 

VLF is the only way to go through water. Unfortunately that is not conducive to data transfer at any reasonable speed. The required antenna size will knock your socks off.

 

How clear is the water. Perhaps a LED.

 

VLF is the only way to go through water. Unfortunately that is not conducive to data transfer at any reasonable speed. The required antenna size will knock your socks off.

I don't think so. Radio does work in fresh water, and coiled antennas can be used. Interested to see if anyone has direct experience with this.

 

This will get to 5m underwater and appears to be able to use a 2.4GHz wireless camera underwater!
http://seagifts.com/raconewyofi.html

 

Hello,

Have a look at the attached PDF.

Bertus

 

This will get to 5m underwater and appears to be able to use a 2.4GHz wireless camera underwater!
http://seagifts.com/raconewyofi.html

Thank you!

 

Hi WaterRunner,

This is a known and (to an extent) solved problem. The people who did so are the Radio Controlled Submarine enthusiasts. In a nutshell, provided the vhf dipole antenna is COMPLETELY sealed against water ingress, you can get a range of around 50 metres tops, in fresh water.
These links should help you out:
https://en.wikipedia.org/wiki/Radio-controlled_submarine (look at the reference links at the end of this article, which includes the pdf link which Bertus provided in post #6)

http://www.rc-submarines.net/radios.html

 

Hi WaterRunner,

This is a known and (to an extent) solved problem. The people who did so are the Radio Controlled Submarine enthusiasts. In a nutshell, provided the vhf dipole antenna is COMPLETELY sealed against water ingress, you can get a range of around 50 metres tops, in fresh water.
These links should help you out:
https://en.wikipedia.org/wiki/Radio-controlled_submarine (look at the reference links at the end of this article, which includes the pdf link which Bertus provided in post #6)


Thanks Sitara, this is highly relevant.

 

Thanks Sitara, this is highly relevant.