A moisture content sensor comprising a signal source (400) arranged to provide a signal, a probe (9) arranged to inject the signal into a medium (6) in which the moisture content is to be measured, a complex impedance (4) placed between the probe (9) and the signal source (400) and sensing electronics (7) arranged to monitor the signal at a point between the signal source (400) and the complex impedance (4) and generate a primary measurement therefrom which is indicative of the moisture content of the medium (6).