An experiment for calibrating the high-frequency Stark effect in a turbulent plasma is presented. The electrostatic turbulence is created by injecting an electron beam into a pulsed low pressure arc discharge. Microwave measurements of the unstable wave yield information on the validity of the applied theoretical model and permit a determination of the field strengths. Spectroscopic observation of plasma satellites as well as of an enhanced inelastic excitation of spectral lines confirm these values.