The BR189 is an air cooled transmitting triode that can produce up to 80 kW output as a Class C amplifier at up to 5 MHz. For operation at reduced ratings the maximum operating frequency is 50 MHz. The valve has a thoriated tungsten filament and the peak cathode current can be 70 Amps.
EEV is an abbreviation of English Electric Valve.
The copper to glass seal can be seen. The two discs are anti-corona rings and designed to evenly distribute the electric field so as to prevent a corona discharge when HT is present.
Within the glass is the bright copper anode and the inverted cone holding the grid.
The base of the copper anode with cooling fins attached.
The makers label. Strange that the word magnetron is present on a forced air cooled triode.
The wide metal tube envelope is 256 mm in diameter, and excluding the base pins is 448 mm tall.