The VR28 is the UK RAF pre-CV code for the commercial 220VSG.
The data-sheet talks of manual control of the bias point. This was at a time before the widespread use of the superhet in UK domestic receivers and the TRF (Tuned Radio Frequency) or straight set was the norm.
This exhibit has the old stores code of 10E/8399 under the Type designation. The up arrow indicates RAF.
The reverse is plain zinc paint screening paint with c code of 805V printed onto it.
The presence of the screw top cap suggests that this was made before 1935. From the early to mid 1930s the metal top had top cap became the norm.
The original box. Plain card with just the stores code.
The balloon envelope is 41 mm in diameter, and excluding the B4 base pins is 111 mm tall.
References: Data-sheet & 1043. Type VR28 was first introduced in 1931. See also1931 adverts.
