The lamp G-811 is a triode with a high gain

Glow voltage    6.3V
Incandescent current   4.0±0.25A
The maximum anode voltage is   1250 V
Gain factor (Ia=20mA U s=-2..0V)   144..176
The current in the anode circuit is   16..36 m A
The maximum anode current is      125mA
The steepness of the characteristic is 3.4 m A/V
The internal resistance is 10 Kohm
Output power
((Ua=1.5 KV Ia=150 mA)
135W (15 MHz)
125W (60 MHz)
The maximum power dissipated by the anode is 40W
Input capacity 5.0±1.5pF
Output capacity 0.6±0.2pF
The passing capacity is 4.8..6.2pF