E1188

This was the very early multicavity magnetron designed by E.C.S. Megaw, the leader of the GEC laboratories, starting from the prototype developed by Randall and Boot at the Birmingham University. Megaw himself designed the filament seal assemblies, which supported the filament, and the end enclosures. End spaces were riduced to the minimum, in order to fit the magnetron in an electromagnet with 7 cm. gap.
The six-cavity anode block cylinder was supplied by Birmingham, drilled using a revolver chamber as drilling template. The cathode was of tungsten and the E1188 was basically a water-cooled CW unit, capable of delivering about 500W at 10 cm wavelenght. It needed a 50 lbs bulky electromagnet to operate.
E1188 was designed starting from 10th April 1940 and by May 16 a sample was already working, with performances similar to those of the Birmingham University prototype. No volume production was launched, the tube being redesigned as E1189 for pulsed operation.