Similar to this question, a need a wireless transmitter for underwater, both fresh and salt water. Vertical range needs to be a few 100 meters, and underwater depth only 2 meters. The power supply will be a battery and the device needs to be able to run for a few hours.

Receiver will always be above water. And only one-way communication is necessary. The data that is sent is only a few bytes big, or two (decimal) floating points representing coordinates.

Any ideas in which direction I should start searching?

  • \$\begingroup\$ Fresh or salt??? \$\endgroup\$
    – user16324
    Commented Aug 30, 2016 at 13:01
  • \$\begingroup\$ Both fresh and salt. I'll alter the question. \$\endgroup\$ Commented Aug 30, 2016 at 13:02
  • \$\begingroup\$ Only 2m underwater: Could you float an RF transceiver or antenna on a tether to the unit underwater? \$\endgroup\$
    – scorpdaddy
    Commented Aug 30, 2016 at 13:08
  • \$\begingroup\$ I'm confused by your apparently contradictory specs. "Vertical range" "few 100 meters" or "underwater depth only 2 meters". And when you use the term "wireless" do you truly mean any method which doesn't require a wire, or are you implying radio only? Would fiber-optic be acceptable or is that too close to wired? \$\endgroup\$
    – brhans
    Commented Aug 30, 2016 at 13:23
  • \$\begingroup\$ Perhaps you could use an ultrasonic transmission instead? Ultrasonic waves are transmitted much better in the water. Update: Oh, I've missed the part where the receiver is above the water... \$\endgroup\$
    – Eugene Sh.
    Commented Aug 30, 2016 at 14:07

1 Answer 1


Going to need some more details. Will both the transmitter and receiver be located underwater? What sort of power budget do you have? What sort of data rate do you need? Do you need bidirectional communication or only one-way?

RF is probably out due to attenuation in the water, but optical and acoustic may be reasonable options.


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