The evidence for the "dodgy radar" is weak. According to Klass' informant, the second F4 was briefly quarantined after the incident and returned to active duty less than a week later, and the only thing they found was some static on the radio. It was called in abouth a month later for radar adjustment.Jupiter is brilliant enough to be seen from 500 million miles. The question is, can it be observed accurately at night by a pilot flying an F-4 with an apparently dodgy radar?
Klass' informant was relating a story he heard from a Shahroki technician, so this information was second hand.
Source: attached file, bottom of page 8 of the pdf.
And yes, Jafari could see Jupiter right from his takeoff. But he first saw the object from 70 NM, i.e., halfway his trip to Tehran.