A method of controlling bandwidth allocation over a communications link comprising detecting, by a processor, a change in a power level of a composite signal transmitted by a transmitter, the composite signal comprising a plurality of carrier signals and having a constant center frequency and spectral allocation, adjusting at least one of a modulation factor and a forward error correction (FEC) rate of one or more of the plurality of carrier signals using a modulator, in response to the change in power level to maintain a predetermined data rate and spectral allocation of the composite signal, and maintaining, by the modulator, an uninterrupted communications link between the transmitter and a remote receiver while the at least one of the modulation factor and the FEC rate is adjusted.