The CV1281 (formerly the NR64) receiver valve is a variable μ amplifier beam tetrode equivalent to the KTW61.
Gain controlled amplifier stages are found in RF and IF sections of superhet receivers. The control grid is connected to the top cap.
Serial number?
The beam tetrode construction can be seen with the beam plates covering the ends of the grid axis. The control grid is wound on copper supports for good heat transfer.
The top of the valve with the electrode supports appearing through the slot in the top screen. The tape connecting the control grid to the top cap is visible as is the rectangular cathode tube.
The classic envelope is 38 mm in diameter and, excluding the IO base pins, is 104 mm tall.
