gu-74b

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 (V_a = 1KV, V_g2 = 300V, I_a = 600mA, change in V_g1 = 2.5V), mA/V: 32.5

Anode current (I_a) with V_a = 2.5KV, V_g2 = 300V, A: >1.4

Negative bias (V_g1) with V_a = 1KV, V_g2 = 300V, I_a = 600mA, V: 18-32

Negative cutoff bias (V_g1) with V_a = 1KV, V_g2 = 300V, I_a = 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, V_a = 2KV, V_g1 = -60V, V_g2 = 300V, I_g2 < 50mA, Freq. 0.1-1.0 MHz, W: >550

3rd-order energy relative to carrier, V_a = 2KV, V_g2 = 300V, I_g2 < 50mA, V_g1 = -70V, dB: -28

5th-order energy relative to carrier, V_a = 2KV, V_g2 = 300V, I_g2 < 50mA, V_g1 = -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 (V_a), KV: 2

Maximum Instantaneous value Anode voltage (V_a), KV: 4

"Maximum" Control Grid voltage (V_g1), V -150

Maximum Screen Grid voltage (V_g2), V 300

CW cathode current (I_c), A: 0.75

Peak cathode current (I_c), 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

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



*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 (V_a = 1KV, V_g2 = 300V, I_a = 600mA, change in V_g1 = 2.5V), mA/V:	32.5
Anode current (I_a) with V_a = 2.5KV, V_g2 = 300V, A:	>1.4
Negative bias (V_g1) with V_a = 1KV, V_g2 = 300V, I_a = 600mA, V:	18-32
Negative cutoff bias (V_g1) with V_a = 1KV, V_g2 = 300V, I_a = 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, V_a = 2KV, V_g1 = -60V, V_g2 = 300V, I_g2 < 50mA, Freq. 0.1-1.0 MHz, W:	>550
3rd-order energy relative to carrier, V_a = 2KV, V_g2 = 300V, I_g2 < 50mA, V_g1 = -70V, dB:	-28
5th-order energy relative to carrier, V_a = 2KV, V_g2 = 300V, I_g2 < 50mA, V_g1 = -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 (V_a), KV:	2
Maximum Instantaneous value Anode voltage (V_a), KV:	4
"Maximum" Control Grid voltage (V_g1), V	-150
Maximum Screen Grid voltage (V_g2), V	300
CW cathode current (I_c), A:	0.75
Peak cathode current (I_c), A:	2.5
Anode Dissipation, W:	600
Screen Grid (G2) Dissipation, W:	15
Control Grid (G1) Dissipation, W:	2
Frequency, MHz:	<250