The CV2933 (commercially the 2C46) is a disc seal valve where the grid connects to an external ring. This separates the valve into two distinct regions, the cathode below the grid and the anode above. The spacing between the electrodes is small to allow operation at UHF and above.
In the USA such valves are called lighthouse valves because of their construction. The disc seal valves are used at UHF frequencies as grounded grid amplifiers. In use the valve would be sealed in a resonant cavity.
The KB/DF identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the DF identifies the maker as Mullard Radio Valve Co., Waddon.
There are no markings on this side.
The grid is made in two parts. The centre part has the fine wires tightly stretched across the centre hole. In effect this forms a frame grid.
The planar envelope is 18 mm in diameter, and excluding the IO base pins is 52 mm tall.
