The presence of this minimum creates a special channel known as Deep Sound Channel, previously known as the SOFAR ( sound fixing and ranging ) channel, permitting guided propagation of underwater sound for thousands of kilometres without interaction with the sea surface or the seabed.
2.
The Garpun-Bal radar combines active and passive channels and in the active target designation mode, it operates in X-band ( I / J-band ) and can handle up to 150 targets at ranges between-, although it is possible to obtain ranges of more than in wave-guide propagation conditions.
मोबाइल