The 6SA7GT is a heptode and was designed as a self oscillating mixer for radio reception, also known in the US as a pentagrid converter.
The base carries the National Union name and Logo. Grid two, oscillator anode, is made from the supports and small strips of metal. The strips appear to be foldes at 90 degrees and so face the inner grid at 45 degrees either side of the support. The g3 support is at right angles to the line of the other grids.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 62 mm tall.
References: Datasheet & 1043. Type 6SA7GT was first introduced in 1940.
Absolute Maximum Operating Conditions¶
Updated March 12, 2015. shape:wide.glass.tube construction:pinch type:heptode age:1940.1950 base:io heater:6.3v pins:8 pin:1.m pin:2.h pin:3.a pin:4.g2.g4 pin:5.g1 pin:6.k.g5 pin:7.h pin:8.g3