GI-39b
Triode

The GI-39B triode generates and amplifies RF oscillations in pulsed operation with anode modulation. Rated to 1200 MHz at 440W plate dissipation. It is a direct replacement for the older (discontinued) GI-14b, and can also be used to replace the GS-1b and GS-31b at slightly reduced power levels for amateur applications.

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GENERAL
Cathode:  indirectly heated, oxide-coated.
Envelope:  metal-ceramic with ring leads of cathode, heater and grid.
Cooling:  forced air.
Height, mm, at most: 147
Diameter, mm, at most: 100.2
Mass, kg, at most: 1.2
gi-39b side view gi-39b diagram
A - anode; C - grid; KP - cathode and heater; P - heater
ENVIRONMENTAL OPERATING CONDITIONS
Vibration loads:
frequency, Hz 2-2,000
acceleration, m/s² 4.9-98
Multiple impacts with acceleration, m/s² 343
Linear loads with acceleration, m/s² 294
Ambient Conditions:
Temperature, °C -60 to+150
Relative humidity at up to +40 °C, % 95-98

NOMINAL ELECTRICAL PARAMETERS
Heater voltage (AC or DC), V 12.6
Heater current, A 3.7
Mutual conductance, mA/V 30
Operating point (negative Vg with Va = 2KV, Ia = 250mA), V 7
input capacitance, pF 23
transfer capacitance, pF 5.5
Warm up time, s, at most 90
Designed Tube Life (hours) >500

ELECTRICAL PARAMETER LIMITS
Heater voltage, V 12-13.2
Heater current, A 3.4-3.9
Operating point (negative Vg with Va = 2KV, Ia = 250mA), V 4.5-10
input capacitance, pF 21-25
transfer capacitance, pF 4.2-6.3
Mutual conductance, mA/V 27-36
Maximum Peak value Anode voltage (Va), KV: 20
Peak value Anode current (Ia), A 16
Maximum Peak bias (Vg), KV 1
Maximum Peak Grid current (Ig), A 7
Average Anode Dissipation, W: 440
Average Grid Dissipation, W: 5
Temperature at anode terminal, °C 200
Temperature at cathode terminal, °C 150
Temperature at grid terminal, °C 180
Temperature anode insulator, °C 250
Minimum Wavelength, cm 25

gi39b-1
Averaged Peak Characteristic Curves:
Uf = 12.6V; t = 2µs; frequency 1,000 imp/s;
_____ anode;
_ _ _ grid-anode
gi39b-2
Averaged Peak Characteristic Curves Showing Oscillator Output Power versus Anode Current:
Uf = 12.6V; Ua imp = 20kV; t = 2 µs; frequency 1,000 imp/s
gi39b-3
Averaged Peak Characteristic Curves:
Uf = 12.6V; t = 2µs; frequency 1,000 imp/s;
_____ anode-grid;
_ _ _ grid
gi39b-4
Characteristic Curves Showing Flow Rate of Envelope Cooling Air versus Anode Dissipation:
_____ at 100°C;
_ _ _ at 160°C