Communication means for communicating wireless signals within a hydrocarbon well, the communication means comprising: - at least one first communication means (107, 302) configured to be located in a first portion within the well, the first communication means (107, 302) comprising at least one signal transmitter or at least one signal transceiver (107, 302); and - at least one second communication means (103, 301) configured to be located in a second portion of the well, at least one of said first (107, 302) or second (103, 301) communication means being configured for association with an activation system for a downhole device, wherein the at least one signal transmitter (107, 301) or at least one signal transceiver (107, 302) is defined by a connector, a housing and a flexible membrane, said flexible membrane being arranged for transferring to a well fluid oscillations provided by an actuator located in a portion of the housing, characterized in that the flexible membrane is coupled to the actuator via a coupler device, the coupler device being a hydraulic device comprising a piston with a micro orifice and a cylinder filled with hydraulic oil, the oscillations being transferable from the actuator into the hydraulic oil via the piston and from the hydraulic oil into the cylinder, said cylinder body being arranged to transfer said oscillations into the flexible membrane, the micro orifice being configured to allow for sufficient fluid flow to match the relatively slow deflection movement of the membrane so as to compensate for deflections of the membrane as the transmitter (107, 301) is run into the well whereby the coupler device enables a controlled deflection of the membrane without imposing damaging stresses to the actuator, but still providing an optimal transfer of oscillations from the actuator to the membrane. - at least one first communication means (107, 302) configured to be located in a first portion within the well, the first communication means (107, 302) comprising at least one signal transmitter or at least one signal transceiver (107, 302); and - at least one second communication means (103, 301) configured to be located in a second portion of the well, at least one of said first (107, 302) or second (103, 301) communication means being configured for association with an activation system for a downhole device, wherein the at least one signal transmitter (107, 301) or at least one signal transceiver (107, 302) is defined by a connector, a housing and a flexible membrane, said flexible membrane being arranged for transferring to a well fluid oscillations provided by an actuator located in a portion of the housing, characterized in that the flexible membrane is coupled to the actuator via a coupler device, the coupler device being a hydraulic device comprising a piston with a micro orifice and a cylinder filled with hydraulic oil, the oscillations being transferable from the actuator into the hydraulic oil via the piston and from the hydraulic oil into the cylinder, said cylinder body being arranged to transfer said oscillations into the flexible membrane, the micro orifice being configured to allow for sufficient fluid flow to match the relatively slow deflection movement of the membrane so as to compensate for deflections of the membrane as the transmitter (107, 301) is run into the well whereby the coupler device enables a controlled deflection of the membrane without imposing damaging stresses to the actuator, but still providing an optimal transfer of oscillations from the actuator to the membrane.