Lecher wires is a circuit segment consisting of two parallel wires or rods joined by a coupling loop on one end, the other end being open. A shortcircuiting bar is moved along the wires to vary the effective length of the circuit. Radio-frequency energy is inductively coupled into the system through the loop, and the bar is slid along to various response points, as indicated by a meter or lamp coupled to the wires. The frequency can be determined by measuring the distance between adjacent response points. It is used at very-high frequencies (VHF), ultra-high frequencies (UHF), and microwave frequencies. Also called Lecher frame and Lecher lines.