ESTAR experience with RFI at L-band and implications for future passive microwave remote sensing from space

Although the spectral window at 1.413 GHz (L-band) is protected for passive use, radiometers for remote sensing commonly encounter problems with RFI. Experience with the synthetic aperture radiometer, ESTAR, suggests that airports are one source of this RFI. The existence of RFI at L-band could be a problem for future remote sensing from space.