The radio compartment is aft of the bomb bay section, and is reached from the flight deck by a catwalk through the bomb bay.
This is a view of the firewall at the rear of the radio compartment - looking toward the rear of the plane. The cranks on the wall are to manually crank down the landing gear and the wingflaps. The units on the left are transmitters used to jam enemy radar. Once a signal was picked up, one transmitter was used to jam that signal as others were received and jammed simultanesouly. Each operator was capable of jamming three signals at the same time.