A system to monitor gain in a broadband radio frequency transport system that includes a radio frequency antenna, a remote unit, and a host unit adapted to receive a signal from the remote unit over a transmission link. The remote unit includes a pilot tone generator adapted to generate at least one single-frequency tone having a known power level, a summing circuit operably associated with the pilot tone generator adapted to sum the single-frequency tone with the respective received radio frequency signal. Each host unit includes a pilot tone receiver circuit to receive the transmitted signal and detect the single-frequency tone transmitted over the transmission link. The host unit includes a controller to determine a gain within the transmission link and to determine if the gain is in a preset range of gains based on the power level of the received pilot tone.