Frequency Modulated Continuous Wave radars used for most civilian radar altimeters sweep most of 200 MHz bandwidth, largest known case is 196 MHz. Transmit power ranges between 0.1 to 100W.[1]

As another commenter mentioned, making a broadband filter for such wide bandwidth is... problematic, and it's one of those devices where you might want to use fixed function rather than SDR.

[1] https://www.icao.int/NACC/Documents/Meetings/2018/RPG/RPGITU...