TB 11-6625-821-35
11. Direction Finder Control C-6899/ARN-83
a. Performance Procedure
(1) The unit under test is connected to its power source.
(2) Turn the function switch on Direction Finder Control C-6899/ARN-83 to ADF,
and set the DC POWER switch on the unit under test to ON.
(3) Turn the range switch on Direction Finder Control C-6899/ARN-83 to 850-1750,
and rotate the TUNE control until the hairline on the FREQUENCY indicator bisects the
small circle located between 1400 and 1500 kc.
(4) The BEARING INDICATOR on the unit under test should indicate 240 1.0
degrees.
(5) Rotate Direction Finder Control C-6899/ARN-83 TUNE control until the
FREQUENCY indicator indicates 1700 kc.
(6) The BEARING INDICATOR on the unit under test should indicate 204 1.0
degrees.
(7) Rotate Direction Finder Control C-6899/ARN-83 TUNE control until the
FREQUENCY indicator indicates 850 kc.
(8) The BEARING INDICATOR on the unit under test should indicate 344 1.0
degrees.
(9) The tuning meter should be deflected to midscale.
(10) Set the DC POWER switch to OFF.
b. Adjustment
(1) The unit under test is connected to its power source. Connect the AC VTVM to
P-3 Receiver Pendant Cable: positive to Pin 9 and negative to Pin 11. Ground pin E of J1
on Bearing Indicator.
(2) Remove Direction Finder Control C-6899/ARN-83 by loosening the four Dzus
fasteners. Reconnect the cable attached to it after removing the rear cover of Direction
Finder Control C-6899/ARN-83.
(3) Rotate the TUNE control until the hairline on the FREQUENCY indicator
bisects the small circle located between 1400 and 1500 kc.
(4) Set the DC POWER switch on the unit under test to ON.
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