GU-74B / 4CX800A
POWER TRANSMITTING TETRODE

     The GU-74B is a ceramic-metal forced-air cooled tetrode intended for use as a linear SSB-signal amplifier with output power up to 550 W at frequencies up to 75 MHz and as a power amplifier in wideband amplifier service at the frequencies up to 250 MHz. The tube can be used in stationary and mobile equipments and it is especially effective at low anode voltage (1 - 2 kV) with high efficiency (>50%) 

CHARACTERISTICS

Anode Dissipation (PD) 600 W
Screen Dissipation (Pg2) 15 W
Grid Dissipation (Pg1) 2 W
Frequency for Max. Ratings (f) 250 MHz
Cathode Oxide coated
Heater voltage (UF) 12.6 V
Heater current (IF) 3.6A
Transconductance at Ua = 1 kV; Ug2 = 300 V; Ia = 600 mA 32 mA/V

Capacitances (ground cathode connection)
     Input, (C1)
     Output, (C2)
     Feed-through, (Cag1)


50 pF
11 pF
<0.09 pF
Max. Seal and Envelope Temperature 200° C
Maximum Length 90 mm
Maximum Diameter 72 mm
Weight (approximate) 550 g
Operating Position Any
Blower 35 m3/h

 

Class of
Operation 		Type of Service Max. Ratings Typical Operation
Anode
Voltage,
kV 		Screen
Voltage,
V 		Cathode
Current,
mA 		Anode
Voltage,
kV 		Screen
Voltage,
V 		Anode
Current,
mA 		Output
Power
W
AB1 RF Linear Amplifier at
75 MHz 		2.2 350 750 2 300 450 550

Intermodulation distortion of the 3rd order - minus 30 dB

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