Design Constraints for RFI Nulling at the ATA
Gerry Harp (SETI Inst.) gharp@seti.org

The Allen Telescope Array is a new 350-element radio telescope currently under construction in Northern California. Single-tap beamformers combine signals from all these elements to provide 16 simultaneous dual-polarization beams on the sky. We intend to leverage the large-N aspect of this array to perform RFI nulling in the beamforming process, and have developed new techniques that operate in a single-tap beamformer. We point out that for moving RFI sources, beamformer coefficients must be controlled on a surprisingly fast time scale and have a complex temporal structure. Because the SKA is larger and may observe at shorter wavelengths, beamformer constraints there will be even tighter.