The 5A/163K is an HF pentode with a high mutual conductance and high anode current. The high current would aid in the attaining of a low noise figure. The valve, CV1635, was used by the UK GPO.
Through the outer screen the strap connecting the two anode plates can be seen. Below the lower mica is an additional screen.
looking along the grid axis shows clearly the two anode plates some distance from the central grids and cathode. The grids pass flat across the face of the cathode.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 46 mm tall.
References: Data-sheet & 1040. Type 5A/163K was first introduced in 1956. See also1956 adverts.
