The STC V246A/1K is a Heil Tube. Named after its German inventor, the Heil tube is a velocity modulated oscillator and the Heil tube was developed by STC during WWII. Unlike the klystron the electron beam in the Heil tube is focused by an external magnet. This refinement was originally added to keep the bunched electrons together as the electric charge would, of course, tend to repel the electrons one from another.
The standard CV designation was CV288 and a selected number were alternatively designated CV485. The copper disc is internally connected to the resonator at pin 6.
The bottom is the shield followed by heater/cathode, grid and screen grid. The copper tube provides the drift space and the anode is at the top.
The shield is in the forground with the heater wires visible on the right.
The support rod in the centre is spot welded to the resonator tube and to the copper disc on the left.
The B7G base.
The anode is shaped and not a flat plate.
The lower end of the copper resonator is connected to base pin six. At the upper right can be seen the heater leads.
The thin glass tube envelope is 19 mm in diameter, and excluding the B7G base pins is 75 mm tall.
Reference: Datasheet. Type V246A/1K was first introduced in 1957.