The A0897 is a metal-ceramic high-μ triode designed for grounded grid operation. The A0897 has an anode dissipation of 10 Watts and operats at a maximum frequency of 2.5 GHz.
This exhibit was rescued from a VHF power amplifier. The valve was mounted in a box section cavity 38 mm square. The depressions seen in the brass anode had circular brass discs sitting in them and these were held in place by wide screw studs into the housing. The connections to the valve were made with circular gold plated finger stock.
The anode has a deep cylindrical hole in it and in use the tuning of the amplifier was achieved by sliding a slug into the the top of the anode.
The picture shows the filament end. There is only three connections besides the anode, thus confirming this valve as a triode. The normal configuration in use would have probably been in the grounded grid mode.
The thin metal tube envelope is 22 mm in diameter at its widest and overall the valve is 76 mm long.