Sensibly equivalent¶ to:
The VR53 is a WWII lend/lease valve made in the US to a British/European specification. Except for a few majestic types no US domestic valves used metallic spray coatings. This was because from the mid-1930s onwards most new US valve designs were either in metal envelopes or, for RF types, had integral internal shields.
Thus, when the US Government agreed to source British-designed electronic equipment for the war effort the US valve manufacturers had to come to terms with metallic spray coating and the difficulties of getting it (and the base cap) to stick properly under tropical (damp) conditions. That they succeeded rather better than some British manufacturers is evidenced by comparing this exhibit with some of the home-brewed ones! See VR53.
The valve is a screened variable μ pentode designed for radio receiver use. The frequency range of operation would be up to 30 MHz and it was probably used as an IF amplifier. Type EF39 is essentially the same valve specification.
The VR in the designation designates this as a pre-WWII Royal Air Force receiving valve.
The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 82 mm tall.
References: Datasheet & 1040. Type VR53 was first introduced in 1940.
Absolute Maximum Operating Conditions¶
Updated December03, 2012.