TB 9-6625-003-35
(6) Reduce test oscillator amplitude to minimum and set ratio transformer to
.100000.
(7) Set METER SCALE switch to EXPAND and adjust test oscillator amplitude for -
a 0-dB indication on TI meter 0 to 10 DB scale.
(8) Adjust ratio transformer controls until TI meter indicates 2 on 0 to 2 (2.3) DB
scale. If ratio transformer does not indicate between .061660 and .064565, perform b
below.
NOTE
Steps (9) through (13) pertain to models 415B and 415BR only.
(9) Repeat (6) above.
(10) Set METER SCALE switch to NORMAL and GAIN control fully clockwise.
(11) Adjust test oscillator amplitude, and TI GAIN control if necessary, for a 0-dB
indication on TI meter 0 to 10 DB scale.
(12) Set METER SCALE switch to -5 DB.
(13) Adjust ratio transformer for a 0-dB indication on TI meter 0 to 10 DB scale.
Ratio -transformer will indicate between .309030 and .323594.
b. Adjustments
(1) Set ratio transformer controls to .063096.
(2) Record TI meter error from 2-dB mark on 0 to 2 (2.3) DB scale.
(3) Adjust R33 (R53 for model 351) (fig. 5) until an equal error is indicated on
opposite side of 2-dB mark (R).
21. Attenuator Accuracy (AN/GSM-256 only)
a. Performance Check
(1) Connect equipment as shown in figure 6.
(2) Set attenuators (A1 and A2) to 0 (zero) dB.
(3) Adjust test oscillator (A9) frequency for 1 kHz and amplitude for an up-scale
indication on SWR meter (A8).
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