The 6SA7 is a heptode designed as a self oscillating mixer for radio reception. This exhibit is the original metal version. The heptode is known in America as a Pentagrid converter.
The USA Government procurement code of VT-150 is also on the can.
Test results.
The RCA logo and Made in USA.
The thin metal tube envelope is 25 mm in diameter and, excluding the IO base pins, is 51 mm tall.
References: Data-sheet, 1040 & 1043. Type 6SA7 was first introduced in 1937. See also1937 adverts.
