The CV57 is a beam tetrode designed as a pulse modulator for WWII radar magnetrons. This type of duty places great demands on the cathode and subsequent developments in 1942 replaced these beam tetrodes with the CV85 trigatron for magnetron modulation.
These high values for voltage and current are peak values. The maximum anode dissipation is 15 Watts and the screen dissipates up to 0.5 Watts.
We understand that the CV57 was used in pairs connected in parallel to pulse modulate the AI Mk VIII Radar in late 1941. The magnetron used in this Radar was the CV64.
The construction is substantial with a ceramic lower insulator/support. The filament is a coated wire that passes through a pair of flat faced box cathodes.
The anode is blackened for good heat radiation. Inside the anode is a bright box structure and this is the beam plates.
Looking into the side of the anode cavity the beam plates passing up from the bottom is clearly visible. Also visible is the screen grid. Note that the screen grid is wound with substantial wire.
The base pins are set in a ceramic filling to the bottom of the valve. Note the side pin that locates in the skirt of the base unit.
The base unit is a ceramic ring with a metal support skirt for the bayonet fitting valve. The ceramic ring is 87 mm in diameter and 20 mm high. The metal skirt is 50 mm in diameter and overall the base is 59 mm tall.
The pins rotate in the socket and are held between the ceramic side wall and the metal spring.
This magnificent exhibit was donated by Marcel van de Gevel from the Netherlands. Many thanks.
The classic envelope is 51 mm in diameter, and excluding the special base pins is 173 mm tall.
