The Man Overboard Indicator (MOBI) system is a personal saltwater-activated man overboard (MOB) alarm system utilized by the US Navy and other mariners. The alarm system includes a transmitter, receiver and direction finder. A DSC (digital selective calling)-capable radio is also used with the TX-106 transmitter (p/n: ORCATX-106).

The TX-106 is worn on the MK-1 float coat and the inherently buoyant life preserver (IBLP) and transmits on 156.525 MHz and 121.5 MHz.  When activated, it emits an RF signal which calls the DSC-capable radio. The radio sounds upon receipt of this signal, indicating the identity and GPS coordinates of the MOB. The transmitter also emits a signal which is processed by the direction finder, providing a continuous bearing to the MOB.



» Weight: 4 oz. (113.398 g)
» Power Source: One (1) CR123 lithium battery
» Battery Life: One year (Armed mode); 24 hours continuous once activated (Transmit mode)
» Activation: Saltwater
» Modulation Frequencies: 156.525 MHz (Channel 70 DSC-VHF); 121.5 MHz (Distress/Direction Finding)
» External antenna with flexible strain relief
» Operating Temperature -20º C (-4º F) to +55º C (131º F)
» Storage Temperature -30º C (-22º F) to +70º C (155º F)
» Meets IP67 watertight standard


TX106-Manual (PDF)