Telephonics RDR-1600 - Check and Adjust Antenna Stabilization

TM106601_(7/01) 2-20
USE OR DISCLOSURE OF DATA CONTAINED ON THIS PAGE IS SUBJECT TO THE
RESTRICTION ON THE TITLE PAGE OF THIS DOCUMENT.
COMMAND SYSTEMS DIVISION
2.8.2.2 Check And Adjust Antenna Stabilization
Note
+ The pitch and roll output levels from the
vertical gyro are governed by the 115 volt, 400
Hz excitation, the linearity of the gyro, plus the
ability of the gyro to follow the motion of the
aircraft. The accuracy contributed by the
antenna is its ability to respond to the gyro
outputs. As a result of these factors, the
stabilization system accuracy can vary up to
±10% of the pitch or roll angle of the aircraft.
This accuracy can be tested in flight by
performing the following procedure.
(1) Fly to a convenient altitude above 10,000 feet.
(2) Select a range of 80 nautical miles, or 40-mile range for 12-inch antennas. Set the mode to
SRCH 3.
(3) Pull the PULL STAB OFF switch (on tilt control pot) out on the Radar Control Panel to
remove antenna stabilization.
(4) While flying level (0° pitch, 0° roll), adjust the TILT control on the Radar Control Panel to
obtain the video pattern shown in Figure 2.9-1, then note TILT control setting. The terrain
band should be displayed about the third range mark.
If the inner ring of video is not parallel to the range mark, the error is caused by mechanical
displacement of the antenna about the roll axis of the aircraft. Use TILT control to determine
exact error. Correction on the ground, if necessary, must be performed prior to further in-flight
calibration.
(5) Push the PULL STAB OFF switch (on tilt control pot) in on the Radar Control Panel to restore
antenna stabilization.
(6) The pattern observed in step (4) should not change. If the pattern shifts as in Figure 2.9-2 or
Figure 2.9-3, it will be necessary to ground-check leveling of the gyro and accuracy of the
Horizon Situation Indicator. Use TILT control to find exact error.
(7) Roll the aircraft 20° right. For perfect stabilization, the terrain band shown in Figure 2.9-1
should not shift.
(8) In step (7), if the terrain band shifts as shown in Figure 2.9-2, increase the tilt angle, by means
of the TILT control on the Radar Control Panel, until the pattern is similar to Figure 2.9-1.
Note
+ Note the new position of the TILT control. It
should not be more than two degrees above
that noted in step (4).