A SiC single crystal is produced by the solution growth method in which a seed crystal attached to a seed shaft is immersed in a solution of SiC dissolved in a melt of Si or a Si alloy and a SiC single crystal is allowed to grow on the seed crystal by gradually cooling the solution or by providing a temperature gradient therein. Further, the distal end can include an end formation forming a curved contact surface at the distal end, and the end formation can be displaced to one side of the principal longitudinal axis. The relay stations include means for receiving and sending telecommunications signals from and to said ground stations and from and to other relay stations.