GI39b 
Triode 
The GI39B 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) GI14b, and can also be used to replace
the GS1b and GS31b at slightly reduced power levels for amateur applications.

GENERAL  
Cathode: indirectly heated, oxidecoated.  
Envelope: metalceramic 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 
A  anode; C  grid; KP  cathode and heater; P  heater 
ENVIRONMENTAL OPERATING CONDITIONS  
Vibration loads:  
frequency, Hz  22,000 
acceleration, m/s²  4.998 
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, %  9598 
NOMINAL ELECTRICAL PARAMETERS  
Heater voltage (AC or DC), V  12.6 
Heater current, A  3.7 
Mutual conductance, mA/V  30 
Operating point (negative V_{g} with V_{a} = 2KV, I_{a} = 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  1213.2 
Heater current, A  3.43.9 
Operating point (negative V_{g} with V_{a} = 2KV, I_{a} = 250mA), V  4.510 
input capacitance, pF  2125 
transfer capacitance, pF  4.26.3 
Mutual conductance, mA/V  2736 
Maximum Peak value Anode voltage (V_{a}), KV:  20 
Peak value Anode current (I_{a}), A  16 
Maximum Peak bias (V_{g}), KV  1 
Maximum Peak Grid current (I_{g}), 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 
Averaged Peak Characteristic Curves: U_{f} = 12.6V; t = 2µs; frequency 1,000 imp/s; _____ anode; _ _ _ gridanode 
Averaged Peak Characteristic Curves Showing Oscillator Output Power versus Anode Current: U_{f} = 12.6V; U_{a imp} = 20kV; t = 2 µs; frequency 1,000 imp/s 
Averaged Peak Characteristic Curves: U_{f} = 12.6V; t = 2µs; frequency 1,000 imp/s; _____ anodegrid; _ _ _ grid 
Characteristic Curves Showing Flow Rate of Envelope Cooling Air versus Anode Dissipation: _____ at 100°C; _ _ _ at 160°C 