Abstract: A pair of contact or capacitive HF couplers for drill stem components. Each of the first and second couplers includes a central conductor, a supplemental conductor, and an annular dielectric mechanism. The dielectric mechanism is disposed between the conductors. The conductors are isolated from each other. The supplemental conductor includes two electrical contact surfaces. The central conductor includes an electrical contact surface or electrode such that the couplers are capacitive. The central conductors of the first and second couplers interact electrically in the coupled state. The supplemental conductors of the first and second couplers are in electrical contact in the coupled state. The supplemental conductors surround the central conductors. In the mounted state, the supplemental conductors form a shielding for the central conductors.

Abstract: A pair of contact or capacitive HF couplers for drill stem components. Each of the first and second couplers includes a central conductor, a supplemental conductor, and an annular dielectric mechanism. The dielectric mechanism is disposed between the conductors. The conductors are isolated from each other. The supplemental conductor includes two electrical contact surfaces. The central conductor includes an electrical contact surface or electrode. The central conductors of the first and second couplers interact electrically in the coupled state. The supplemental conductors of the first and second couplers are in electrical contact in the coupled state. The supplemental conductors surround the central conductors. In the mounted state, the supplemental conductors form a shielding for the central conductors.

Abstract: A system and method for controlling the time occupation of signalling frequencies is disclosed, in a frequency hopping system including a plurality of remote stations communicating under control of transceivers with a transceiver of a base station, such communication being performed over a shared medium through a sequence of frequency hopping periods in a plurality of operating frequencies. The method consists in selecting a set of signalling frequencies among the operating frequencies, and interleaving signalling messages transmitted on each signalling frequency within each frequency hopping period to allow a remote station to enter the network for the first time or by re-acquiring synchronization, by scanning each signalling frequency for receiving a signalling message.