Type VT-232 (E1138) is a WWII VHF/UHF power amplifier/oscillator. The VT- indicates a valve specified by the USA Government.
Essentially this valve is a development of type 6J5GT (q.v.) with grid and anode taken out through short and stubby low-inductance leads. To improve the operating frequency two top caps are used, one for anode and one for the grid.
In the UK the same design process resulted in the DET20 which was named type CV6 for government procurement. In both cases the need was for a VHF/UHF oscillator triode that became widely used in WWII radars. The μ value is 20, which is about favourite for RF oscillators.
The triode section is mounted horizontally above the pinch to give best access to the top caps.
The single thread oxide coated heater connects at each side.
Looking down, the anode is stitched together and is blackened for better heat radiation.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 73 mm tall.
References: Private communication & Data-sheet. Type VT-232 was first introduced in 1943. See also1943 adverts.
