One of the first scientific goals of the Allen Telescope Array is the detection of interstellar deuterium through the DI transition at 327 MHz. This is a novel experiment for RFI mitigation since we accumulate the astronomy signal from autocorrelations from each antenna but also compute cross-correlations. These cross-correlations can be used for RFI migitation since they resolve out the deuterium signal. We describe measurements of the interference environment at long wavelengths at the Hat Creek site and our early attempts at measuring the deuterium signal with the ATA.