My farther Mr Sidney Rodda was one of the EMI engineers who developed the beam tetrode valve.
I understand that while he was with EMI he was also part of the team which designed the EMI television system subsequently used by the BBC.
My father was also the witness in the post war trial concerning who had designed and patented this valve.
After about a year with EMI he returned to Cosmos at Ponders End Enfield makers of the MAZDA valves.
I am not quite sure what my father would have designed during the war as it was all covered by the Official Secrets Act.
My father was formidable mathematician at a time when calculations would take weeks or even months to conclude.