Since the SDRplay RSP family of devices ‘thinks’ in terms of ‘gain reduction’ (i.e. attenuation), the values you want to assign to the IF and RF gain are always negative: for instance the IF gain goes from -20 (highest signal gain) to -59 (lowest signal gain); similarly the gain values for the RF gain go from 0 (highest signal gain of the RF chain) to -N, where the value of N depends on the specific RSP device and frequency band, as per the ‘Gain Reduction Tables’ in the SDRplay API Specification guide (https://www.sdrplay.com/docs/SDRplay_API_Specification_v3.09.pdf) on page 38.