Description (AMM 34-57-01)

 

A- The ADF (automatic direction finder) 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 kHz.

 

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 ADF systems are installed in the airplane. Each system consists of a receiver, sense antenna, sense antenna coupler, fixed loop antenna, quadrantile error corrector and control panel. Location of the components is shown in Fig. 1.

 

C- ALL EXCEPT AIRPLANES WITH A 614L-13 ADF CONTROL PANEL;

Operation and mode selection of the ADF receiver is remotely controlled by its control panel on the flight deck. The receiver uses signals from both the sense and the fixed loop antenna to compute the compass bearing to the radio station.

 

D- AIRPLANES WITH A 614L-13 ADF CONTROL PANEL;

Both ADF systems are controlled by a common dual-system control panel. Operation and mode selection of each ADF receiver is remotely controlled from its half of the dual control panel on the flight deck. The receiver uses signals from both the sense and the fixed loop antennas to compute the compass bearing to the radio station.

 

E- The ADF system interfaces with two RDDMI's (radio digital distance magnetic indicators) and the flight interphone system. The RDDMI's display the compass bearing to the radio station. The flight interphone system provides switching and audio monitoring equipment to handle the audio output from the automatic direction finder receiver.

 

The ADF system also interfaces with two EFSG's (EFIS symbol generators). When selected, the EHSI's display the compass bearing to the radio station.

 

F- The ADF systems obtain 28 volt dc and 115 volt ac power from circuit breakers on load control centers P18 and P6. ADF No. 1 system power is from the standby bus on load control center P18 and ADF No. 2 system power is from ELEX bus 2 on load control center P6.