GU-74b
Tetrode

The GU-74b tetrode is used in wideband nontunable amplifiers and for single-sideband power amplification in stationary and mobile RF equipment. It is useful at full ratings through 250MHz. The GU-74b tetrode is generally considered to be similar to the 4CX800A, although some users report that it acts more like a tube having 900 or 1000W anode dissipation.


GENERAL
Cathode:  indirectly heated, dispenser, oxide-coated.
Envelope:  metal-ceramic.
Cooling:  forced air.
Height, mm, at most: 90
Diameter, mm, at most: 71
Mass, gm, at most: 550
GU-74b GU-74b
GU-74b
I - contact surfaces; 1 - grid 1; 2, 4, 6 - cathode; 3, 7 - heater; 5, C2 - grid 2; A - anode

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

ELECTRICAL PARAMETER LIMITS
Heater voltage, V 11.9-13.3
Heater current, A 3.3-3.9
input capacitance, pF 46-56
output capacitance, pF 9-13
Maximum CW Anode voltage (Va), KV: 2
Maximum Instantaneous value Anode voltage (Va), KV: 4
"Maximum" Control Grid voltage (Vg1), V -150
Maximum Screen Grid voltage (Vg2), V 300
CW cathode current (Ic), A: 0.75
Peak cathode current (Ic), A: 2.5
Anode Dissipation, W: 600
Screen Grid (G2) Dissipation, W: 15
Control Grid (G1) Dissipation, W: 2
Frequency, MHz: <250

gu-74b
gu-74b

gu-74b
gu-74b

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  gu-74b

gu-74b
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gu-74b
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gu-74b