Why can'y we use lower than 30 MHz radar IF?

i've been told by a radar operations and maintainance person that typical Intermediate frequency values for microwave radars are from 30-120 MHz. why can't we use lower frequencies(e.g 500kHz) as that would reduce the required sampling rate for DSP and make real time implementation alot easier(becoz of reduced data rates).

The hight IF is the best beacause the if filter i gaussian and adapted at the pulse duration.

BP=1.2/τ.

this is the best result of signal noise ratio.

the pulse duration depend of the minimal resolution in distance (150m/μs).

agree!