Sensibly equivalent¶ to:
The VR65 ia a WWII military receiving pentode valve made for the RAF. The VR in the designation provides this information. Commercially this is an SP61 that was developed originally for television RF stages. The SP41 is the same electrically but has the pre-war 4.0 Volt standard heater.
With the grid at the top cap, this is the normal pattern for RF and IF amplifier valves of the period. Providing high gain in tuned anode circuit applications. For additional screening the valve is covered with an external metalisation.
The VR65 was used in air-borne radar particularly GEE.
The reverse is plain but has a single S near the base.
The classic envelope is 32 mm in diameter and, excluding the MO base pins, is 81 mm tall.
References: Datasheet & 1043. Type VR65 was first introduced in 1941.
Absolute Maximum Operating Conditions¶
Updated April 03, 2015.