Externally, the installation of the new radar can be distinguished by the presence of a new radome which has fore and aft strengthening ribs. A new, much taller UHF blade antenna is mounted on the dorsal spine, and the lower UHF antenna on the undercarriage door is larger in size. This pod has a wide range of modules and has reprogrammable software which make it capable of quickly countering new threats. This missile has a launch weight of about 1345 pounds and is powered by a Nissan Motors solid rocket engine. It has midcourse guidance provided by an inertial system acting in conjunction with a radar altimeter which maintains an altitude just above the tops of the waves during the final run-in to the target.
Terminal guidance is provided by an active radar seeker mounted in the nose.
Plans to fit slatted wings to the F-4EJ Kai were ruled out on the basis of cost. A new inertial navigation system was fitted, as well as an infrared reconaissance system, digital cockpit displays, and a VHF radio to replace the existing UHF system. Some confusion has resulted from this conversion, since these aircraft are also designated RF-4EJ Kai. The first example converted was 37-6406. The first F-4EJ Kai flew in 1984, and the 306th Hikotai accepted its first example on November 24, 1989.