The CV5397 lighthouse planar triode was designed to provide RF power in broadband microwave circuits. The commercial equivalent was the Mullard EC157. The circuit topography that the CV5397 was designed for was grounded grid. The grid sits across the width of the valve and the grid connection is fitted with a screw thread for direct fixing into a cavity based enclosure.
The numbers on the base shell.
The mesh seen at the lower end of the glass tube is just a support for the long cathode tube. The heater and flat emissive surface is at the top of this closed tube. The dimensions are such that it was not possible to image the grid structure.
The anode connection and below the screw thread of the grid connection.
The thin glass tube envelope is 18 mm in diameter, and excluding the base pins is 45 mm tall.
