MIL-PRF-1/1753C
TABLE I. Testing and inspection - Continued.
19/ The tube shall be mounted such that the high-voltage bushing is shielded and the waveguide output is connected
to a length of waveguide. The mounting plate shall have a thermal mass equal to 5 pounds of aluminum.
The tube shall be operated until thermal equilibrium is reached and the body temperature is at least 90șC. All
power and cooling shall be removed. After a period of no greater than 2 minutes, the tube shall be immersed in
water at 4șC and left for a period of 3 minutes. This test shall be repeated 3 times. During immersion water shall
not be allowed to enter the waveguide nor touch the high-voltage bushing.
2
20/ The vibration amplitude shall be 0.0125 g /Hz, 10 Hz to 2 kHz. The maximum number of missing pulses shall be
0.25 percent when measured as stated in note 17/, except the load shall be matched.
21/ The radio frequency bandwidth and side lobes shall be within the limits specified when a VSWR of 1.5:1
minimum is introduced in the load and the phase is adjusted at the start of each measurement to produce
maximum degradation. A satisfactory spectrum is one whose slope does not change sign more than once for
power levels greater than 6 dB below its peak.
22/ The seal formed by clamping the tube mounting plate against a suitable tube test fixture shall be hermetically
tight for 1 minute minimum with the specified air pressure applied so as to surround the entire input bushing
below the mounting plate.
23/ The seal formed by clamping the tube output flange against a suitable tube test fixture shall be hermetically tight
for 1 minute minimum with the specified air pressure applied internally to the test fixture.
24/ The tube shall be coupled directly to M3922/59-007 choke flange modified so that mounting holes provide
clearance for No. 8 bolts.
25/ The modulator shall be such that energy per pulse delivered to the tube, if arcing occurs, shall not greatly exceed
the normal energy per pulse. The tube heater shall be protected against arcing by use of a connector that places
a minimum of 4,000 pF across the heater directly at the input terminals.
26/ At the completion of this test, the tube shall meet the power output and pulse voltage requirements of
conformance inspection, part 1.
27/ The pushing factor shall be measure in steps of at least 4 amperes each and no value shall exceed the limits
specified herein. The peak current through the tube shall alternately be the limits as specified under this test
condition. These tests shall be run to exclude the effects of thermal drift and frequency instability not due to
pushing.
28/ In addition to regular markings the tuner dial settings for the following frequencies shall be marked on the tube.
The accuracy of these settings shall be ±5 MHz at the start of life under conditions of test condition (2) with the
anode temperature approximately 80șC as measured at the point specified on figure 1 when tuning is performed
in the order of increasing the frequency.
Frequency code Dial setting
F1
----
F2
----
F3
----
29/ Starting at F1 and increasing to F3, then decreasing to F1, the frequency of the tube will be changed in 200 MHz
increments (approximately) after each 50 hours (approximately) of high-voltage operation. The duration of the
switching interval between test conditions 1 and 2 shall not exceed 5 seconds. The following cycle shall be used
for life test:
Condition
Duration (minutes)
Standby
2.5
Test condition 1 5/
25.0
Test condition 2 5/
25.0
Off
7.5
6
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business