Short-range undersea wireless data transmission (inductive)

I’ve tested this inexpensive setup in both fresh and sea water, and I get about 7 meters range (at least 6 meters reliably): keyless,125Khz evaluate demo board RF125 Low Power 125Khz Instead of AS3933 Wireless Air Wake up And Data Transceiver Module|Replacement Parts & Accessories| - AliExpress

It’s extremely low bandwidth (dozens of bits per second) - so useful for sensors and/or control where you don’t want to run wires and plugs, but no good for video streams etc.

It comes with excellent doc - and communicates via plain serial to anything (I’m using Arduino).

Hi Hi,
Where can I obtain more information on this product?
It might be very useful for a small underwater craft I am working on.

Stay safe,

Dubi

I’ve bought one, tested it (works great) so I’ve bought another. You can ask my anything simple if you like. The seller provides extensive documentation and code if you ask for it (more than enough to easily program them).