APG-66(V)2 - upgrade of base radar. New signal processor, higher output power, improved reliability. Range in clutter/jamming environment increased to 83 km.
APG-66(V)2A - AN/APG-66(V)2 with a new combined signal and data processor that provides seven times the speed and 20 times the memory of the older radar computer and digital signal processor line replaceable units. In this new variant, the displayed resolution in ground-mapping mode is quadrupled, and is reported to be close to that offered by Sar techniques. Used for modernization of F-16A/B fleet of Belgium, Denmark, Norway and the Netherlands in the mid-1990s.
APG-66(V)3 - as APG-66(V)2 but with CW illumination capability, possibly for export to Taiwan.
APG-66(V)X - improved version of the APG-66(V)2/3 radar with greater detection range.