The CV187 is high voltage rectifier designed for high power applications. The maximum reservoir capacitor that can be fed is 4 µF and the valve needs a minimum effective series resistance of 600 Ohms.
A pair of these valves would be able to supply sufficient power of a reasonably sized transmitter.
The GEC brand was reserved for valves for professional applications. The ceramic insulators are present because of the high voltages involved.
The top view showing the anode connection to the top cap and the two filament tension springs.
The pinch end. The filament is a coated ribbon in an m formation. The outer ends are in parallel and the centre is the other connection.
The classic envelope is 50 mm in diameter and, excluding the B4 base pins, is 164 mm tall.
References: Data-sheet. Type CV187 was first introduced in 1947. See also1947 adverts.
