How many of these pretty-faced reporters know ANYTHING about the problems of measuring the height of a flying aircraft (whose transponder is disabled)? This is NOT a trivial problem. Here is an entire 40-page chapter of a radar text devoted to the calculations. The problem of determining height by radar is far more complicated than determining range and bearing. Civil aviation flight controllers around the world rely virtually completely upon the transponders reporting of their altitude.
[clipper - a former AF Radar Electronics Officer]