GU39A1
TETRODE
The GU39A1 tetrode is used as a power amplifier in stationary shortwave transmitters
GENERAL
Cathode: directly heated, carbonized thoriated tungsten.
Envelope: glasstometal
Cooling: forced (water for anode, air for stem and envelope)
Height: at most 292 mm.
Diameter: at most 128 mm.
Mass: at most 4 kg
OPERATING ENVIRONMENTAL CONDITIONS  
Ambient temperature, °C  10 to +55 
Relative humidity at up to +25 °C, %  98 
BASIC DATA Electrical Parameters 

Filament voltage, V  6.3 
Filament current, A  85105 
Mutual conductance (at anode voltage 3 kV, grid 2 voltage 1 kV, anode currents 1.5 and 2 A), mA/V  2028 
Gain coefficient (grid 1  grid 2) (at anode voltage 3 kV, grid 2 voltages 1 and 1.2 kV, anode current 1.5 A)  69 
Anode current (at anode voltage 3 kV, grid 1 voltage 100 V, grid 2 voltage 1 kV), A  1 
Negative bias voltage (at anode voltage 8.5 kV, grid 2 voltage 1.2 kV, anode current 0.5 A), V  130190 
Interelectrode capacitance, pF:  
input, at most  80 
output, at most  29 
transfer, at most  0.7 
grid 2cathode, at least  50 
Output power (at anode voltage 10 kV, operating frequency 30 MHz), kW, at least  13 
Limit Operating Values  
Filament voltage, V  66.6 
Anode voltage (DC), kV  10 
Negative grid 1 voltage, V  800 
Grid 2 voltage (DC), kV  2 
Filament starting current, A  150 
Dissipation, W:  
anode  8x10³ 
grid 2  450 
grid 1  200 
Operating frequency (at output power at least 13kW),MHz  30 
Operating frequency (limit value), MHz  100 
Temperature at envelope, stem and seals, °C  150 
Averaged Anode Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1 kV
Averaged Anode Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1.5kV
Averaged AnodeGrid Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1 kV
Averaged AnodeGrid Characteristic Curves:
U_{f} = 6.3V; U_{g2}= 1.5kV
Averaged Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1kV;
_____ grid 1anode;
   grid 2anode
Averaged Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1.5kV;
_____ grid 1anode;
   grid 2anode
Averaged Grid 1 Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1kV
Averaged Grid 1 Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1.5kV
Averaged Grid 2 Characteristic Curves:
U_{f} = 6.3V; U_{g2} = 1 kV
Averaged Grid 2 Characteristic Curves:
U_{f}=6.3V; U_{g2} = 1.5kV