The Microwave Filter Series 7893D C-Band bandpass filter is installed between a TVRO feedhorn and the LNA or LNB to suppress strong out-of band interference caused by marine or airport radar systems. Coastal and marine navigational radar frequencies (2.9-3.65 GHz) are just below the TVRO band and frequently wipe-out transponders 1-5 in TVRO’s installed near harbors. The airport altimeter band (4.25-4.40 GHz) will affect channels 22-24 at TVRO sites near airports. The Microwave Filter model 7893D interference filter operates at RF before down conversion. This prevents the generation of undesirable mixer products and receiver “desensitization” due to strong out of band signals.