Abstract: Wristwatch equipped with a high-frequency transmitter comprising an extensible antenna in the form of a wire wound up in a first housing and a second antenna forming a counterpoise and wound up, before use, in a second housing. These two antennae are each fastened to a plug by means of which the antennae can be unfurled by pulling, the plugs becoming detached when the antennae are completely unfurled.The transmitter essentially constitutes a distress beacon and the presence of a counterpoise antenna has the effect of significantly amplifying the radiating power of the transmitter without consuming additional energy.