TB 9-6625-2278-24
IDENTIFICATION AND DESCRIPTION
1. Test Instrument Identification.
This bulletin provides instructions for the
calibration of Power Meter, Hewlett-Packard, Model 438A and 438AOPT002. The
manufacturer's 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. None
b. Time and Technique. The time required for this calibration is approximately 4
hours, using the dc and low frequency and microwave technique.
2. Forms, Records, and Reports
a. Forms, records, and reports required for calibration personnel at all levels are
prescribed by TB 750-25.
b. Adjustments to be reported are designated (R) at the end of the sentence in which
they appear. When adjustments are in tables, the (R) follows the designated adjustment.
Report only those adjustments made and designated with (R).
3. Calibration Description. TI parameters and performance specifications which
pertain to this calibration are listed in table 1.
Table 1. Calibration Description
Test instrument
Performance
parameters
specifications
Zero set (digital settability of zero)
0.5% FS (most sensitive range)
Decrease percentage by factor of 10
for each higher range l count)
Range: 3 W to 100 mW
Instrument accuracy single channel
mode
Accuracy: 0.02 dB (within same calibration range)
Plus: 0.02 dB (outside calibration range)
Power reference
Range: 1 mW
Accuracy: 1.2%
Frequency: 50 MHz
Accuracy: 0.5 MHz
EQUIPMENT REQUIREMENTS
calibration procedure. This equipment is issued with Secondary Transfer Calibration
Standards Set AN/GSM-287, and AN/GSM-705. Alternate items may be used by the
calibrating activity. 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
