Under Water Communications

Which communication is suitable through water to detect a particular matter?
asked by varperumal

Answer by Sanjay Mishra
Sound waves are usually used inside water for both communication and detection of objects. Remember submarines use SONAR (sound navigation and ranging). You can either look for sound waves without transmitting (passive SONAR) or transmit sound waves and look for their reflection (active SONAR).

RF travels poorly in water, especially salt water The greater the salt content of water the less RF propagates inside it. Extremely Low Frequency (ELF) and Very Low Frequency (VLF) Waves are used to communicate with submarines while they are submerged in water.

If long distance communication is required from submerged objects a common way is to use an acoustic modem from the submerged object to an acoustic modem on a buoy on the surface. The acoustic modem connects to a RF Modem and sends the data over air to a remote location.

In a hundred years, I hope we will be using neutrino emitters and detectors under water!

Hope this helps Sanjay