Microwave Filter's 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 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.