Abstract: An interference signal canceling system for communications protection is described for canceling interference signals from earth station received signals using a two input adaptive cancellation network. The present invention addresses terrestrial, co-channel and adjacent satellite interference sources resulting from emitting, isolated, frequency re-use and polarized sources. Main and auxiliary signals are derived directly or by coherent conversion to intermediate frequency using an auxiliary antenna, cross-polarized feed, or auxiliary squinted feed. Filters set receive and canceling bands. Cancellation combines the main signal with a phase, amplitude and time modulated sample of the auxiliary signal. A receiver correlates the auxiliary signal with a sample of the combined output to minimize interference. A control drives the modulator from internal measurements, or satellite receiver measurements, i.e., BER, C/No, SNR, etc., or both.