TB 9-4931-321-35
IDENTIFICATION AND DESCRIPTION
This bulletin provides instructions for the
calibration of Standing Wave Ratio Meter Hewlett-Packard Model 415E and PRD Model
277D. The manufacturers' manuals were used as prime data sources in compiling these
instructions. The equipment being calibrated will be referred to as the TI (test instrument)
throughout this bulletin.
a. Model Variations. PRD Model 277D differs from the HP Model 415E in this
bulletin by front panel nomenclature and component designation. Where these differences
occur, the PRD Model 277D information is shown in parenthesis.
b. Time and Technique. The time required for this calibration is approximately 2
hours, using the dc and low frequency technique.
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).
pertain to this calibration are listed in table 1.
Test instrument parameters
Performance specifications
Power input
Satisfactory performance w/line voltage between 105 and 125 V ac
Noise level
7.5 dB below FS at rated sensitivity with input terminated in
optimum source impedance
Bolometer Current: Range
8.7 or 4.5 mA
Accuracy
3% into 200 Ω
Attenuator: Range
0 to 70 dB in 10 dB steps
Accuracy
0 to 8 dB in 2 dB steps
0.05 dB per 10 dB step
0.02 dB per 2 dB step
0.02 dB on expanded scale
EQUIPMENT REQUIREMENTS
calibration procedure. This equipment is issued with Secondary Transfer Calibration
Standards Sets AN/GSM-287 or 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
