THIS IS A NEW RUSSIAN POWER TETRODE TUBE GU-74B (4CX800A). IT IS PACKED IN ORIGINAL SOVIET PACKAGE WITH INSTRUCTIONS

Name	GU74B
Type	tetrode
Cathode type	oxide,indirect heating
Application field	power amplification in broadcasting and SSB equipment
Brief application	amplification
Envelope	metall-ceramic
Cooling method	forced air
Dimensions	90mmx71mm
Mass	0.55 kg
Filament voltage	12.6 V
Filament current	3.3 - 3.9 A
Mutual conductance	26 to 38 mA/V
Output power	0.6 kW
Maximum anode voltage	2kV/4kV in peak
Maximum operating frequency	150MHz

ENVIRONMENTAL OPERATING CONDITIONS
Vibration loads:
frequency, Hz	1-200
acceleration, m/s²	49
Multiple impacts with acceleration, m/s²	392
Ambient Conditions:
Temperature, °C	-10 to +55
Relative humidity at up to +35 °C, %	98

NOMINAL ELECTRICAL PARAMETERS
Heater voltage, V	12.6
Heater current, A	3.6
Mutual conductance (Va = 1KV, Vg2 = 300V, Ia = 600mA, change in Vg1 = 2.5V), mA/V:	32.5
Anode current (Ia) with Va = 2.5KV, Vg2 = 300V, A:	>1.4
Negative bias (Vg1) with Va = 1KV, Vg2 = 300V, Ia = 600mA, V:	18-32
Negative cutoff bias (Vg1) with Va = 1KV, Vg2 = 300V, Ia = 15mA, V:	90
input capacitance, pF	51
output capacitance, at most, pF	11
transfer capacitance, pF	<0.09
Warm up time, s:	<150
AB1 Output power, Va = 2KV, Vg1 = -60V, Vg2 = 300V, Ig2 < 50mA, Freq. 0.1-1.0 MHz, W:	>550
3rd-order energy relative to carrier, Va = 2KV, Vg2 = 300V, Ig2 < 50mA, Vg1 = -70V, dB:	-28
5th-order energy relative to carrier, Va = 2KV, Vg2 = 300V, Ig2 < 50mA, Vg1 = -70V, dB:	-28
Designed Tube Life (hours)	>1500