The FM-CW technique is used to perform a partial reflection experiment. This method seems to be the only possibility to overcome the enormous noise level in the frequency range 2–6 MHz in middle Europe. A frequency near 4 MHz is swept by 100 kHz in 1 second and a transmitter power of 50 W is used. The technique, the operation and the data reduction are described. The possibility of measuring the electron density and the collision frequency profiles simultaneously is discussed. Some examples of deduced collision frequency profiles and electron density distributions under normal and anomalous conditions are presented.