The CV9785 has a 26 Volt heater and is built to resist vibration in service. Electrically it is a robust cousin of the 6 Volt 4X150A. For operation beyond 165 MHz it needs to be derated and the anode voltage maximum drops to 1,250.
The CV9785 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.
The spigot has a key to guide the valve into the socket. The control grid connects to the spigot.
The looped tape provides a great surface area for the forced air cooling. Note that the tape is formed with holes and ridges for maximum efficiency.
The grids are of the concentric cage type. A internal view of the QV1-150A can be found here and matches the construction of the CV9875.
The co-axial envelope is 32 mm in diameter and, excluding the B8F base pins, is 46 mm tall.
