The 4CX150A beam tetrode is VHF power tetrode and is designed to be operated in a special base and chimney structure. The valve holder has holes in it to allow air to pass through. The air is contained by the chimney so that the forced air cooling is directed over the large surface area of the anode ruff. Normally the chassis would be sealed air tight and a blower attached to provide a powerful air blast.

This form of valve was very successful and made by several manufacturers from this, the smallest size, to very large power valves such as the 4CX35000C bases range from pin types to co-axial rings. Internally the heater is surrounded by two concentric cage grids. See QV1-150A for details of construction.

The base is a glass disc with pins protruding through. The evacuation seal is covered by a central metal spigot.

The co-axial envelope is 40 mm in diameter and, excluding the B8F base pins, is 44 mm tall.

 
Absolute Maximum Operating Conditions

Tetrode	Vh	Ah	Va	Vs	mAa	Pout	freq	f.max
	6.0	2.6	1250	300	150	195	165	500

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 02 July 2007 {find valves by name}