The AV11 is a high voltage half wave rectifier developed in Australia during WWII when supplies of rectifiers became difficult and higher power radar sets were required. The design and manufacture of both sets and valves was completed in Australia. Full details can be found in the attached .PDF file that comes courtesy of the Museum of Victoria.
The maker AWV is the Amalgamated Wireless Valve Company, Sidney, Australia.
Thanks to Dave Small for sending these images.
Another view of the rectifier.
The anode and W shaped horizontal filament.
The ribbon filament and oval anode. The anode supports are fixed to glass rods that emerge from the pinch.
The classic envelope is 51 mm in diameter, and excluding the UX4 base pins is 133 mm tall.
References: www.museumvictoria.com.au. Type AV11 was first introduced in 1941.