The VT-158 is an unusual American transmitting triode. It was designed for pulse operation at 500 MHz, and would produce 200 kW pulses. It was used in the TPS3 radar.
The envelope contains four valves in two pairs. The anodes are connected together but brought out to twin connections. Tuned lines were fitted to the anode connections, but these have been removed from our specimen.
The inset picture shows the bright helical filament in one cavity. Surrounding the filament is a dull grey wire cage grid. The anode is finned and substantial.
The wide glass tube envelope is 87 mm in diameter and, excluding the base pins, is 200 mm tall.
References: Private communication.
Updated December27, 2011.