Operation Bolo, 2 Jan 1967 ~ Led by WW2 ace Colonel Robin Olds ~ analysts in Hanoi became expert in identifying the more vulnerable F-105 "Thuds" from the F-4 Phantoms, from their radio frequencies & call signs. Olds decided to fly Phantom F-4s using the same routes, altitude, & callsigns as the F-105s, ambushing the MiG-21s that would be guided towards them, expecting to find Thunderchiefs, & when they realized the truth, it would be too late for them, 7 Vietnamese MiG-21s were destroyed.
