The CV5116 is the commercial 3B241M and this one was made by STC and the envelope carries both Type designation.
The CV51116 is an RF power triode designed to work at VHF up to 200 MHz in the grounded grid configuration. The anode dissipation is 15 Watts and the full power output (Class C) is 16 Watts.
The central cathode and grid with shaped anodes either side. The working face of the anode is set to be the width of the grid with wider heat sink sections beyond.
Each half of the anode looks to be subdivided into two with all four parts connecting the the top cap.
The wide glass tube envelope is 29 mm in diameter and, excluding the B8B base pins, is 65 mm tall.
Reference: 3002. Type CV5116 was first introduced in 1958. See also1958 adverts.
