create a scenario in the editor.
place a Cheetah or Tigris somewhere (manned/unmanned)
place an enemy helicopter with guided rockets in some distances between 1-4km around the cheetah or tigris.
try the following while sitting in the cheetah or helicopter:
change the OVD between 1-4km and look at the radar for every setting.
press the key for switching between targets and try to lock the cheetah/tigris/helicopter.
press the normal locking key instead.