Radio Altimeter Bandpass Filter The MFC 21043 is a radio altimeter bandpass filter that is optimized for the Frequency Modulated Continuous Wave Applications from 4245-4365 MHz. It has a measured insertion loss of 1.4 dB with 47.1 dB of attenuation. It is available in a 5 x 1 x 0.75 inch package and weighs 0.65 lbs. Microwave Filter Company