Would Foxhunter not fit on a F-15?
By the time the early FOXHUNTER had come on line, the USAF had ironed out the issues with APG-63. Even then it took the FOXHUNTER to get to Stage 1 to become an effective system by the early 90s - but vastly improved with Stage 2 and Stage 3 in the late 90s and at the turn of the 21st Century. By then the APG-63(V)1 had come into service on the F15C/D. Both RADAR systems had their advantages and disadvantages, and even shared some technology, but when ASR 395 was being considered the APG-63 was unreliable and had demonstrated poor performance. It took an upgrade in 1979 to iron out the initial issues with the
programmable signal processor (PSP) - by then the competition had closed. One Brit exchange Pilot reported that it was not any better than the F4’s RADAR’s performance that he had just come from, but better than the Lightning that he had flown prior to that. It certainly wasn’t showing the performance, in those early days, that it finally proved to have later on the C and D models after the introduction of PSP and other modifications/upgrades.