2007-06-27 13:46:54 · 4 answers · asked by elisdad 1 in Cars & Transportation ➔ Boats & Boating
Very low frequency (VLF) and extremely low freq (ELF) are used to continually transmit messages. These freq. and their long wavelengths can penetrate almost 100 below the water's surface. A submarine either has a long permanently mounted antenna or trails a long wire to receive transmissions. Submarines are passive. They do not reply since any electronic signal can be detected.
2007-06-27 17:03:41 · answer #1 · answered by Richard B 4 · 0⤊ 0⤋
Besides the bouy, there is also a very long wire antenna that they can drag behind the sub and make a very low frequency (VLF) transmission.
Subs arent in constant contact with their headquarters. They get their mission and go and do it, there are scheduled times when they surface, or get close to the surface, in order to send and receive data. The sub isself can also stay underwater indefinitely, however, they must also surface in order to get food, mail, supplies, etc.
2007-06-28 00:00:52 · answer #2 · answered by Mike 3 · 1⤊ 0⤋
They are not exactly sent underwater.
The sub raises a tethered bouy with a radio antenna. Messages are transmitted via radio / satellite to the bouy.
2007-06-27 21:01:30 · answer #3 · answered by Firecracker . 7 · 0⤊ 0⤋
It is secret and we would have to kill you if you were to find out. Only low frequency's travel far thru water. So that eliminates radio waves. Whales are said to signal 1,000 miles in water? Try Wood's Hole Oceanographic Institute.
2007-06-27 20:57:28 · answer #4 · answered by John Paul 7 · 0⤊ 1⤋