So, since HARM seems to have an RCS of ~0,2 m² (https://www.rfwireless-world.com/calculators/Radar-RCS-calculator.html), according to my approximate calculations (including public data of HAWK radars), HAWK site should have a lock onto a HARM at between 6-9 mi (HARM needs 36-50 seconds to travel that distance, which is plenty of time). However in DCS, even "Excellent" difficulty HAWK site (all units "Excellent") doesn't get a single HAWK (MIM-23K TBM) missile of the rail (targeted at an incoming HARM).