Brian Hodgson operates the keying unit and checks the frequency of the signal produced by the appropriate Jason oscillator. This keying unit is possibly a modified form of the model that originally lacked any controls. Every oscillator had to be tuned by hand. To his left is the wobbulator. The long box above the oscillators is a simply a power distribution board fitted with special E＆S mains power plugs, used by the BBC because they were less likely to be stolen.