This note describes a sensitive, wide-range wavemeter, using a capacitance-loaded coaxial line as the resonator. The concentric line has a sliding central conductor, which serves to vary simultaneously the length of the line and the capacitance loading. The electrodes of the capacitor are so shaped as to produce an almost linear relationship between the position of the central conductor and the resonant frequency of the wavemeter. A crystal detector and galvanometer are used to indicate resonance.