An early all glass design of amplifier triode. This valve was specified for VHF low power transmitter use. The anode dissipation is 7 Watts and the full power frequency rating is 300 MHz. The maximum frequency that useful power could be obtained was 400 MHz. Quite advanced.
As with all valves produced in this method the pins are short and equi-spaced around a circle. The evacuation seal is concealed within a metal spigot that enables the valve to be accurately located within the valveholder.
The small triode within the much larger envelope. The anode is blackened to radiate heat and the control grid is both wound on good conducting copper supports and has a heat radiating fin at the top.
The crown and AM of the UK Air Ministry.
The purpose of the skirt with a close fitting flange above is clear as this valve arrived complete with removable metal screening can.
The screen has been extruded as can be seen in the small lines on the side.
The screen is substantial with the metal being 0.8 mm thick. The screen is neither aluminium or steel.
The wide glass tube envelope is 32 mm in diameter and, excluding the B9G base pins, is 56 mm tall.
References: Data-sheet, 1040 & 1043. Type VR137 was first introduced in 1946.