The DET28 was designed as a Class C RF amplifier with an RF output of 35 Watts and a dissipation of 25 Watts. The drive for the rated output was 1 Watts. The DET28 was built for HF use up to 20 MHz
The side view is of the working anode shell. The fin in the centre is for cooling.
The MWT logo of M-OV was reserved for professional valves.
The glass disc base is close to the bottom mica thus reducing lead inductance.
The wide glass tube envelope is mm in diameter, and excluding the B9G base pins is mm tall.