The 4CX35,000C is primarily designed for high power transmitter use at frequencies up to 110 MHz and at the 50 kW level. The 4CX35000C is a special version for use as an anode and screen modulated Class C RF amplifier.
The valve is rated for use as an RF linear amplifier and an AF amplifier or modulator as well as for the main design applications.
In 2002 we know that a pair of these valves are in use for the BBC Radio 5 transmitter.
The filament/cathode is of thoriated tungsten. Although the anode rating is given as 20 kV it would be normal to operate it at about 15 kV. The current would likewise be less than the maximum quoted, probably five to ten amps.
The type designation and manufacturer is clearly printed on the side of the cooling fins.
Cooling is by high volume forced air. The nature of the fins can be seen in both the picture of the lower end of the radiator, and the image of the top of the valve.
The handles at the top of the valve are essential as the valve weighs 22.70 kg.
The wide metal tube envelope is 248 mm in diameter and, is 440 mm tall.
Reference: Datasheet. Type 4CX35000C was first introduced in 1962.