A method of determining a level of a product in a tank, using a radar level gauge system comprising: a transceiver; a probe arranged to extend towards and into the product from a first probe end coupled to the transceiver to a second probe end, the probe comprising a first probe conductor and a second probe conductor being conductively coupled to each other by a probe termination arrangement at the second probe end; and processing circuitry, the method comprising the steps of: generating and transmitting, by the transceiver, an electromagnetic transmit signal (S T); guiding, by the probe, the transmit signal (S T) towards and into the product; returning, by the probe, an electromagnetic reflection signal (S R) resulting from reflection of the transmit signal (S T) at the surface of the product and at the second probe end; receiving, by the transceiver, the reflection signal (S R); determining, based on the reflection signal (S R) and a timing relation between the reflection signal (S R) and the transmit signal (S T), an echo signal exhibiting an echo signal strength as a function of a propagation parameter indicative of position along the probe, the echo signal comprising a composite peak formed by a combination of an echo signal from reflection at the surface of the product and an echo signal from reflection at the second probe end; and determining, by the processing circuitry, the level of the surface of the product based on a propagation parameter value indicative of a first threshold position (Z TH1) along the probe for which the composite peak of the echo signal has reached a predetermined threshold signal strength, and an offset indicative of an offset distance (ΔZ) along the probe from the first threshold position (Z TH1) towards the second probe end. a transceiver; a probe arranged to extend towards and into the product from a first probe end coupled to the transceiver to a second probe end, the probe comprising a first probe conductor and a second probe conductor being conductively coupled to each other by a probe termination arrangement at the second probe end; and processing circuitry, the method comprising the steps of: generating and transmitting, by the transceiver, an electromagnetic transmit signal (S T); guiding, by the probe, the transmit signal (S T) towards and into the product; returning, by the probe, an electromagnetic reflection signal (S R) resulting from reflection of the transmit signal (S T) at the surface of the product and at the second probe end; receiving, by the transceiver, the reflection signal (S R); determining, based on the reflection signal (S R) and a timing relation between the reflection signal (S R) and the transmit signal (S T), an echo signal exhibiting an echo signal strength as a function of a propagation parameter indicative of position along the probe, the echo signal comprising a composite peak formed by a combination of an echo signal from reflection at the surface of the product and an echo signal from reflection at the second probe end; and determining, by the processing circuitry, the level of the surface of the product based on a propagation parameter value indicative of a first threshold position (Z TH1) along the probe for which the composite peak of the echo signal has reached a predetermined threshold signal strength, and an offset indicative of an offset distance (ΔZ) along the probe from the first threshold position (Z TH1) towards the second probe end. generating and transmitting, by the transceiver, an electromagnetic transmit signal (S T); guiding, by the probe, the transmit signal (S T) towards and into the product; returning, by the probe, an electromagnetic reflection signal (S R) resulting from reflection of the transmit signal (S T) at the surface of the product and at the second probe end; receiving, by the transceiver, the reflection signal (S R); determining, based on the reflection signal (S R) and a timing relation between the reflection signal (S R) and the transmit signal (S T), an echo signal exhibiting an echo signal strength as a function of a propagation parameter indicative of position along the probe, the echo signal comprising a composite peak formed by a combination of an echo signal from reflection at the surface of the product and an echo signal from reflection at the second probe end; and determining, by the processing circuitry, the level of the surface of the product based on a propagation parameter value indicative of a first threshold position (Z TH1) along the probe for which the composite peak of the echo signal has reached a predetermined threshold signal strength, and an offset indicative of an offset distance (ΔZ) along the probe from the first threshold position (Z TH1) towards the second probe end.