2007-10-11 07:15:03 · 3 answers · asked by paul p 1 in Science & Mathematics ➔ Engineering
Floating antenna, r/t used at set times
2007-10-11 07:22:33 · answer #1 · answered by Anonymous · 0⤊ 0⤋
In general, they have to surface to receive and transmit. They can pre-arrange certain times to come to the surface to very quickly transmit and recieve (that way they can get back under the water).
Very Low Frequency (30 kHz and lower) radio waves have been used sucessfully underwater, but the power output needed is very great, and the information bandwidth with a 30 kHz carrier is very low also, so it takes a long time to transmit useful information. Also... it is probably one-way communication (receive only at the sub.)
The floating antenna is also used -- the sub remains just below the surface, while deploying the antenna bouy.
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2007-10-11 14:36:52 · answer #2 · answered by tlbs101 7 · 2⤊ 0⤋
They send message attached to the fins of passing sea horses.
2007-10-13 21:00:04 · answer #3 · answered by Anonymous · 0⤊ 0⤋