In this version of the radar measuring the high-frequency microwave pulses are sent along a probe in the form of a cable, rod or coaxial waveguide and reflected from the surface of the measured product. The microwave guide probe of the level gauge allows microwave pulses to reach the measured medium, avoiding interference from process conditions and internal tank designs. The received echoes are processed by the electronics of the transmitter and converted to a level value. If necessary, the rod or cable probe can be shortened on site.