Fill level measuring device having a control unit, which contains a high-frequency generator for generating a transmission signal, an amplifier, an amplifier and an evaluation unit, and a spatially remote probe, which contains a measuring impedance, a reference impedance, a first rectifier and a second rectifier, as well as a connecting line between the control unit and the probe, wherein the rectifier detects the voltage of the transmission signal in the probe, and this voltage is transmitted to the control unit as a first DC voltage signal, and the rectifier converts the probe current in the probe into a second DC voltage signal via measuring resistors, and both signals are supplied to the control unit for the purpose of determining the fill level, wherein the rectifiers are thermally coupled to one another.