TB 9-6625-086-35
SECTION I
IDENTIFICATION AND DESCRIPTION
This bulletin provides instructions for the
1. Test Instrument Identification.
calibration of Power Meter, Hewlett-Packard Models 431B and 431C (AN/USM-260). The
manufacturer's instruction manual was used as the prime data source in compiling these
instructions. The equipment being calibrated will be referred to as the "TI" (test
instrument) throughout this bulletin.
a. Model Variations. Variations among models are described in text.
b. Time and Technique. The time required for this calibration is approximately 1
hour, using the microwave or dc low technique.
2. Calibration Data Card, DA Form 2416. Forms, records, and reports required for
calibration personnel at all levels are prescribed by TB 750-25. DA Form 2416 must be
annotated in accordance with T750-25 for each calibration performed.
3. Calibration Description. TI parameters and performance specifications which
pertain to this calibration are listed in table 1.
Table 1. Calibration Description
Test instrument parameters
Performance specifications
Zero carryover
Less than 0.5% of FS when zeroed on most sensitive scale
Range
0.01 to 10 mw in 7 ranges: -20 to +10 dBm in 5 -dBm steps
Accuracy
Model 431C
From +20C to +35C - .01 mw range, 2% of FS, .03 mw range, 1.5% of
FS; all other ranges, 1% of FS.
From 0C to +55C, 3% of FS on all ranges.
Model 431B
From +20C to +35C, 3% of FS on all ranges.
From 0C to +55C, 5% of FS on all ranges.
SECTION II
EQUIPMENT REQUIREMENTS
calibration procedure. This equipment is issued with the secondary transfer calibration
standards sets 6695-00-621-7877 and 4931-00-525-8175 and maintenance calibration
shelter AN/TSM-55. Alternate items may be used by the calibrating activity when the
equipment listed in table 2 is not available. The items selected must be verified to perform
satisfactorily prior to use and must bear evidence of current calibration. The equipment
must meet or exceed the minimum use specifications listed in table 2. The accuracies listed
in table 2 provide a four-to-one accuracy ratio between the standard and TI. Where the
four-to-one ratio cannot be met, the actual accuracy of the equipment selected is shown in
parenthesis.
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