Radio locating unit for persons in distress

Claim 2

A radio locating unit for persons in distress comprising a radio signal transmitter provided with an aerial for the transmission of a radio signal with a predetermined frequency and a receiver provided with an omni-directional aerial for the receiving of signals with said predetermined frequency, characterized in that the receiver is further provided with a directional receiving aerial and a first change-over contact movable manually from a rest position at which the receiver input is connected to the omni-directional receiving aerial, so that the unit performs as a transceiver suited to respond to any call signal picked up by the receiver with an answer signal automatically transmitted by the transmitter, to an emergency position at which the receiver input is connected to the directional receiving aerial so that the receiver acts as a radio direction finder adapted to pick up answer signals, whereby the transmitter acts as call transmitter and thereby permitting the tracking and location of signal sources.

Claim 3

A radio locating unit as claimed in claim 1, characterized in that it comprises a power supply, a short term timer coupled to said power supply by a second change-over contact which timer is provided with a control button, a long term timer connected to the power supply provided with a control input coupled to the receiver output by a third change-over contact, an electronic change-over switch control inputs of which are connected to said timers and outputs of which are coupled to supply inputs of the receiver and the transmitter so that the actuation of the timers causes the change-over of the change-over switch, for durations differently established by the two timers, from a normal condition of activation of the receiver by the power supply and of disactivation of the transmitter, to a temporary condition of disactivation of the receiver and of activation of the transmitting by the power supply for the broadcasting of short or long duration radio signals according to which timer is the actuating one, a signalling means connectable to the receiver output by the third change-over contact, a supply input of the signalling means is coupled by the second change-over contact to the power supply for connecting the signalling means to the output of the receiver and to the power supply in the emergency position of the unit.

Claim 4

A radio locating unit according to claim 2, characterized in that it comprises automatic repetition means of the activations of the transmitter for transmitting short duration call signals, which means is composed of an electrical connection between the receiver output and a control input of the short term timer, which connection will cause the actuation of the short term timer every time the receiver detects the cessation of a long duration answer signal received till that moment.