Abstract: The linear position of an elongated element (1) is measured using a transmission medium (2). The transmission medium comprises an emitter (3) of microwaves and a receiver (4) of microwaves and has at its one end the elongated element (1) and at its other end an electrical short-circuit (23). An asymmetrical sawtooth standing wave with substantially linear flanks is generated by reflection of the microwaves on the short-circuit (23) and on the elongated element (1). The position of the elongated element is determined by measuring the amplitude of the longer flank of the standing wave with the receiver. The method may be used in difficult circumstances and is suitable to measure mechanical vibrations of high-frequency.