On the other hand, the American side committed several mistakes which make it easier for the Vietnamese to detect and track the aircraft.
And not all of the planes had the same jamming capability.

"(…)Charcoal 01 was at the head of nine B-52Gs in three cells attacking the Yen Vien railroad. Charcoal 01 was one of the ‘unmodified’ G models with the lower powered ALT-6B jammers; this was the first time the North Vietnamese SAM operators had seen the lower powered system, and they were to exploit it with a vengeance."