Sutton tube was the name given to the first reflex klystron, developed in 1940 by Robert W. Sutton of Signal School group at the Bristol University. The Sutton tube was developed as a local oscillator for the receiver of 10cm microwave radar sets. Due to its geometry and long drift space, it suffered from mode jumping through the tuning range. For this reason, from late 1941 onward, it was replaced in many sets by the Western Electric 707A (also known as McNally tube, named by its developer).
The reflex klystron is a type of vacuum tube used to generate microwaves. It is a low-power device used primarily for two purposes: one is to provide a tuneable low-power frequency source for the local oscillators in receiver circuits, and the other, with minor modifications, as a switch that could turn on and off another microwave source. The second use, sometimes known as a soft Sutton tube or rhumbatron switch, was a key component in the development of microwave radar by Britain during World War II. Microwave switches of all designs, including these, are more generally known as T/R tubes or T/R cells.
The Sutton tube is named for one of its inventors, Robert Sutton, an expert in vacuum tube design. The original klystron designs had been developed in the late 1930s in the US, and Sutton was asked to develop a tuneable version. He developed the first models in late 1940 while working at the Admiralty Signals and Radar Establishment. Sutton tubes were widely used in a variety of forms during World War II and through the 1960s. Their role has since been taken over by solid state devices like the Gunn diode, which started to become available in the 1970s. "Rhumbatron" refers to the resonant cavity design that was part of many klystrons, referring to the rhumba because of the dance-like motion of the electrons.