A method and an apparatus for implementing the method for providing transmission of an uninterrupted pilot signal covering the whole antenna sector. The method uses at least two primary pilot signals orthogonal relative to each other in a radio system comprising adjacent directional antenna beams. In the method, primary pilot signals are transmitted in main antenna beams of the antenna pattern in such a way that adjacent main antenna beams have primary pilot signals orthogonal relative to each other, and the widths and directions of the antenna beams are adjusted in such a way that the beams having the same primary pilot signal do not overlap.