First sealed-off travelling wave tube, made by Rudolf Kompfner, England, 1945-1946.

Rudolph Kompfner, an Austrian-born physicist who emigrated to Britain in 1933, invented the travelling wave tube during 1942 at Birmingham University, and subsequently developed it at Clarendon Laboratories, Oxford, and with J R Pierce at the Bell Telephone Laboratories. The first practical application of travelling wave tubes was in terminal and repeater stations which relayed BBC television programmes between Manchester and Edinburgh. A travelling wave tube was used on board the Telstar satellite, launched in 1963, transmitting the first television pictures across the Atlantic through space.