This read-only integer reports the terminal's fade margin in dB, calculated from the Automatic Gain Control as the difference between the receiver's minimum usable signal level and the current wvRxSignalLevel reading. An RF engineer uses this value to judge how much additional signal loss, from rain fade or other attenuation, the link could tolerate before service is affected. For example, a fade margin that has shrunk from 30 dB to 10 dB over time would warn an engineer that the link has much less headroom against a coming storm than it used to.