GU44A
TETRODE
The GU44A tetrode is used as a RF power in amplifier shortwave transmitters
GENERAL
Cathode: directly heated, carbonized thoriated tungsten
Envelope: glasstometal
Cooling: forced (water for anode, air for envelope,
stem and seals).
Height: at most 506 mm.
Diameter: at most 182 mm.
Mass: almost 13kg
OPERATING ENVIRONMENTAL CONDITIONS  
Ambient temperature, °C  10 to +55 
Relative humidity at up to +25 °C, %  98 
BASIC DATA Electrical Parameters 

Filament voltage, V  12.6 
Filament current, A  170200 
Mutual conductance (at anode voltage 1.5 kV, grid 2 voltage 1 kV, anode currents 8 and 12A),mA/V  5575 
Gain coefficient (grid 1  grid 2) (at anode voltage 1.5 kV, grid 2 voltages 1 and 1.4 kV, anode current 8 A)  4.26.2 
Interelectrode capacitance, pF:  
input, at most  300 
output, at most  55 
transfer, at most  4 
Negative cutoff voltage (at anode voltage 10 kV, grid 2 voltage 2 kV, anode current 0.5 A), V, at most  700 
Limit Operating Values 

Filament voltage, V  1213 
Anode voltage (DC), kV  12 
Negative grid 1 voltage, kV  1.5 
Grid 2 voltage (DC), kV  2 
Filament starting current, A  300 
Dissipation, kW:  
anode  50 
grid 2  3.2 
grid 1  1.2 
Operating frequency (at output power 70kW), MHz  32 
Temperature at envelope, stem and seals, °C  150 
Averaged Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 1.5kV;
_____ anode;
_ _ _ grid 2anode;
— x — P_{a max} (GU44A);
— . — P_{a max} (GU44B)
Averaged Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 2kV;
_____ anode;
_ _ _ grid 2anode;
— x — P_{a max} (GU44A);
— . — P_{a max} (GU44B)
Averaged Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 1.5kV;
_____ anodegrid;
— . — grid 1;
_ _ _ grid 2
Averaged Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 2kV;
_____ anodegrid;
_ . _ grid1;
_ _ _ grid 2