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Oct 20/91  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-55-11 Page 401 

H25273
DME Antenna Installation (Typical)  500 
34-55-11  Figure 401  May 15/80 
Page 402 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

I. Apply fillet of aerodynamic smoother around antenna base using sealing gun or tube.
NOTE: Make certain no air is trapped during filling. Overfill to allow for smoothing and leveling.
J. Use spatula to smooth compound to an even 45-degree fillet. Remove excess compound.
K. Perform system Adjustment/Test (Ref 34-55-0).
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Oct 20/91  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-55-11 Page 403 

DME INTERROGATOR - REMOVAL/INSTALLATION
1.  General
A.  The DME Interrogator is installed in the main equipment center on shelf E2. The unit is shock mounted and held in place by two hold down hooks.
2.  Remove DME Interrogator
A.  Open DME 1 and DME 2 (when installed) circuit breakers on P6 and P18 panels.
B.  Disconnect cable connectors on front of interrogator (if required).
C.  Loosen hold-down fasteners at front of unit, and pull out interrogator.
3.  Install DME Interrogator
A.  Slide interrogator into rack and secure.
B.  Connect cable connectors on front of interrogator (if required).
C.  Close circuit breakers opened in step 2.A. above.
D.  Test interrogator for satisfactory operation as follows:
(1)  
Provide electrical power.

(2)  
On appropriate VHF NAV control panel, tune frequency display to local VOR/ILS station. Check captain's and first officer's DME indicator for appropriate readout. If no local VOR/ILS station is available, perform DME system test (Ref 34-55-0 Adjustment/Test).

(3)  
Remove electrical power if no longer required.

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Jun 20/84  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-55-21 Page 401 

AUTOMATIC DIRECTION FINDER SYSTEM - DESCRIPION AND OPERATION
1.  General (Fig. 1, 2)
A.  The automatic direction finder (ADF) system is a navigational aid that receives radio signals and determines the direction of the signals relative to the airplane. Signal sources utilized are standard broadcast and low frequency radio range stations operating in the frequency range of 190 to 1750 kilohertz. The system is used for either automatic or manual determination of compass bearing to a transmitting station, for reception of weather information and other broadcast programs, and for flying radio ranges.
B.  Two separate and completely independent automatic direction finder systems are installed in the airplane. Each system consists of a receiver, sense antenna, sense antenna coupler, fixed loop antenna, quadrantal error corrector and control panel.
C.  Operation and mode selection of each automatic direction finder receiver is remotely controlled from its control panel on the flight deck. The receiver uses signals from both the sense and the fixed loop antennas to compute the compass bearing of the radio station being received and converts the information into a synchro transmitter output.
D.  Each automatic direction finder system interfaces with the flight interphone system (23-52-0) and the captain's and first officer's radio magnetic indicators (RMI's). The RMI bearing pointers display the magnetic bearing to the received ADF station provided by the synchro transmitter output from the automatic direction finder receiver. Additional description, operation, and maintenance instructions for the RMI's are provided in 34-21-0, Compass System. The flight interphone system provides switching and audio monitoring equipment to handle the audio output from the automatic direction finder receiver.
2.  Loop Antenna (Fig. 1)
A.  The fixed loop antenna is a sealed, nonrotating, direction-sensitive rf pick-up device for the automatic direction finder system receiver. The antenna consists of two pairs of ferrite core coils, one pair oriented parallel to and the second pair oriented perpendicular to the fore and aft axis of the airplane. Both coil pairs are coupled to the system receiver through the quadrantal error corrector and loop antenna transmission cable.
B.  The fixed loop antennas are flush-mounted from outside in individual antenna cavities on the bottom center of the fuselage at stations 560 and 600 and have no moving parts.
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Oct 20/84  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-57-01 Page 1 
　
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