MIL-PRF-1/1755B
TABLE I. Testing and inspection - Continued.
Limits
Unit
Symbol
Conditions
Test
Notes
Method
Inspection
Min
Max
Conformance
inspection, part 3
hours
---
1,250
29/, 30/
Group D; VSWR = 1.5 cycled
1, 2
Life test 29/ 30/
cycles
---
1,500
through λg every 15 minutes
(approximately)
Life-test end points: 2/
2/
W
---
70
Po
4250
2
Power output
MHz
2.5/tpc
---
BW
4308
1, 2
RF bandwidth 21/
21/
dB
---
6
Ratio
4308
1, 2
Minor lobes 21/
21/
%
0.5
---
MP
4315
2
Stability 17/
17/
1/
Unless otherwise specified, the acceptance level for all tests listed under conformance inspection, part 1, shall be accept on
zero failures.
2/
If during life test, the tube does not meet the specified limits, it shall be recycled for an additional five cycles. At such time, the
tests shall be repeated. The tube will be considered satisfactory if it passes the second test.
3/
The tuning mechanism shall be capable of withstanding a static torque of 75 inch-ounce at the ends of its travel.
4/
The tube shall be capable of normal operation without electrical breakdown with the input bushing in air at normal atmospheric
conditions.
5/
Prior to the application of high voltage, the cathode shall be heated to the required initial operating temperature. This shall be
done by applying 13.75 volts ±5 percent for 150 seconds, minimum. On the application of anode voltage, the heater voltage
shall be reduced in accordance with the following schedule:
Ef = 13.75 (1 - Pi ) ±5 percent; for Pi = 0 to 370 watts; where Pi = epy x Ib.
530
6/
The characteristics of the applied pulse shall be those which result in proper starting and oscillation. The rate of rise of the
voltage pulse, the percentage of pulse voltage ripple, and the rate of pulse voltage fall are among the most important
considerations.
7/
The rate of voltage (rrv) shall be expressed in kilovolts per microsecond (kV/”s) defined by the steepest tangent to the leading
edge of the voltage pulse above the 70 percent amplitude point amplitude point. Any capacitance used in the viewing
(measuring) circuit shall not exceed 6 picofarads (pF).
8/
In handling and mounting the magnetron, care shall be exercised to prevent demagnetization. See figure 1. The use of
magnetic inspection tools is prohibited.
9/
With a total airflow of approximately 20 cfm at approximately 760 mmHg, 25șC divided equally and directed through the cooling
fins toward the body of the tube from two ducts placed 0.750 inch (19.05 mm) maximum from cooling fins, the specified rise
above ambient temperature shall not be exceeded.
10/ Temperature measurements shall be made only after thermal equilibrium has been reached. The frequency shall be measured
at the extremes of any 30șC temperature difference in the specified temperature range.
11/ The tube shall be subjected to five shocks of the specified peak amplitude and duration in each of three mutually perpendicular
directions. Following impact tests, the tube shall show no mechanical failure and shall meet the power output and pulse voltage
requirements of conformance inspection, part 1.
4
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