Gain settings on SDR Play’s RSPduo Software Defined Radios

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.