MIL-PRF-1/1757B
TABLE I. Testing and inspection - Continued.
Conditions
Symbol
Inspection
Limits
Unit
Method
Min
Max
Conformance
inspection, part 3
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No voltages
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Torque 6/ 8/
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Condition A; no voltages;
1042
Shock, specified pulse 6/
fixture
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Torque and shock test
end point:
”A dc
-10
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Ic
1266
Total grid current
1/ All tests listed under conformance inspection, part 1, shall be performed at the conclusion of the holding period.
2/ Test shall be conducted in a power amplifier cavity as shown on figure 2. Driving power is defined as the net power delivered
to the amplifier cavity input terminals and the reflected power shall be subtracted from the incident power to obtain the net
driving power. The output tuning shall be adjusted for maximum power output.
3/ The electrode voltage (2) grid test may be performed alternately in the following manner:
Eb = 600 V dc; Ec/Ib = 1.0 mA dc; and the limit for Eco shall be -18.0 V dc (max).
4/ Grid-anode resonance. Test in cavity. Cavity shall resonate at 1,354 ±2.0 MHz with tuning slug at TA = 25±5șC.
Grid-cathode resonance. Test in cavity. Cavity shall resonate at 1,719 ±2.0 MHz with tuning slug at TA = 25±5șC.
W hen plotted on graphs of resonant frequency versus grid-anode capacitance and resonant frequency versus grid-cathode
capacitance, the tube under test shall be represented by a point within a parallelogram whose four corners are located by the
following points:
Points
Capacitance (pF)
Frequency (MHz)
C-gp
C-gk
F-gp
F-gk
1,740
2,035
6.60
1.65
1
1,770
2,075
6.60
1.65
2
1,705
1,940
7.80
1.90
3
1,735
1,980
7.80
1.90
4
5/ At zero hours, establish the drive conditions necessary to obtain ib = 2.0a (peak anode current) with Eb = 1,000 V dc and a
bias voltage Ec = -40 V dc. the pulse width (tp) of the modulator shall be 2 ”s minimum and the duty (Du) shall be 0.0025
maximum. W ith the drive level determined at zero hours, check the anode current at end of life and measure Cgp. Ćib and
ĆCgp may not exceed the specified limits.
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