Originally Posted by Richard5
If it were encrypted couldn't a single ideogram be sent rather than an entire block of information. The sender and the intended recipient(s) would know that a single word would mean an entire course of action which does not need to be said.
Yeah... The Old North Church "One if by Land; Two if by Sea" type thing? You're delving into cryptology (one of its aspects,anyway) which is all well and good for certain uses. Example: contacting a submerged submarine via ELF, Extremely Low Frequency, with a freq range of zero to 300 Hz. That needs a transmitting antenna
about 14.0 to 28 miles long, though.
But sound signals, audio, are in the range of 20 Hz to 20,000 Hz. (Plus or minus some, we need not quibble the exact range. To avoid argument let's bump it up to 40,000 Hz.) And sounds can be generated with underwater speakers the size of a child's hand. Heck - no need to repeat the whole concept
of sonar here in the thread.
Still, even with compression
formulas a data bit is a data bit and effective "WiFi" would require, what, a minimum 56 KBytes transfer rate? 56,000 X 8 = 448,000 bits and is just a tad over the 40,000 number for audio.
But to run with your query: using pre-agreed codes? Yes, communications
of a SPECIFIC nature would be possible. EG: "diver in trouble", or, "return to surface ASAP", or "cocktails at 16:30 hrs". But that's not underwater "WiFi" where the diver's hand-held camera
transmits (sans wires) up to the cockpit
some colour, real time, live action images
of the local coral fish
But it's an interesting concept
. And it's a start.