A receiver unit comprising a mixer, a test signal unit, a multiplexer unit, an amplifier unit, a signal strength unit, and a digital control unit is described. The mixer may be arranged to downconvert a received radio-frequency signal to an intermediate frequency, thereby generating a reception signal having the intermediate frequency. The multiplexer unit may be connected to the mixer and to the test signal unit and arranged to select, among the reception signal and a test signal, a multiplexer output signal in dependence on an operating signal. The amplifier unit may be connected to the multiplexer unit and arranged to amplify the multiplexer output signal, thereby generating an amplified signal. The signal strength unit may be connected to the amplifier unit and arranged to generate a signal strength indicator indicative of a signal strength of the amplified signal. The control unit may be connected to the signal strength unit and arranged to generate the operating signal in accordance with an operating cycle, the operating cycle comprising one or more test phases and a reception phase. The test signal unit may be connected to the control unit and arranged to generate the test signal in dependence on the operating signal, the test signal having the intermediate frequency. The control unit may be further arranged to: gather, in each of the test phases, a test value of the signal strength indicator, thus gathering one or more test values; determine a numerical transformation on the basis of the one or more test values; gather, in the reception phase, a reception value of the signal strength indicator WO; and compute a corrected signal strength value by applying the transformation to the reception value.