The 4J33 is an S band pulsed magnetron operating within the range 2.78 to 2.82 GHz. This exhibit is marked with the operating frequency of 2.811 GHz.
The 4J33 was the prototype for the CV1916.
The paper label shows that this valve was withdrawn from service in 1986 after 1,280 hours of operation.
The output probe is shielded by the metal cylinder on the side.
The fibreglass plate with the filament and cathode connections. The anode is connected to the body of the case and held at earth potential.
The safety warning sticker.
The end plate has been replaced with a glass disc and the internal structure can be seen. The output loop can be seen in the cavity on the right. The anti-mode strapping connecting poles of like polarity can be clearly seen.
The heat radiating fins are 128 mm in diameter and 30 mm thick.
The wide metal tube envelope is 50 mm in diameter and, including the base pins, is 260 mm tall.
Reference: Data-sheet. Type 4J33 was first introduced in 1945.