A small-size transmitting apparatus for search and rescue operation (SARTR) adapted to be worn by a user for emitting a microwave rescue signal upon a marine accident involving the user. The SARTR includes a power supply, a transmitter unit energizable by the power supply and having a microwave oscillator,...http://www.google.es/patents/US4673936?utm_source=gb-gplus-sharePatente US4673936 - Rescue transmitter apparatus
