Melmothtv,
You are probably fond of science fiction and thrillers, aren't you?. There is no such an aircraft as MiG-28, and it never existed. This fictitious index first appeared in a novel ("The Sinkiang Executive" by EllestonTrevor) in late 70's and then migrated to Top Gun and likes.
The reality is the following. As I wrote above, the Soviet air force was indeed impressed by "F-5E vs Mig-21" test results. It is written in the memoires of Col. Kondaurov (an AF test pilot who flew both MiG-21 and F-5E in those tests in 1976) that the immediate reaction was instruction to MiG-21 pilots to avoid maneuvering at a speed less than 800 km/hr (below which F-5E had an advantage). At that time there was a war between Somali and Ethiopia and these aircraft were in the possession of sides.
http://rulibs.com/ru_zar/nonf_biogra...rov/0/j49.html
(sorry it's in Russian, just to show that a proof link exists).
However, its copying made no sense to SU because Mig-29 was already in the development since 1974 (and its maiden flight took place in 1977). Its in-house competitor, Su-27, also first flew in 1977 though the design worked started even earlier, in 1971 (note that F-5E was brought into Russia in 1976). Both MiG-29 and Su-27, even their early versions, were more advanced than F-5E and were purposed to oppose F-16 and F-15 that already appeared in US in mid 70's.
P.S. I heard that Chinese copied F-5 (as they used to copy everything).
Classic ;-).
OK, then I disavow my first para with apologies. However, there are so many "smiles" in the menu to add "colours" for stupid ones like me
No problem A Van, if you were being 'funny' in Russian I probably wouldn't get it either. Best.