Description

AUTOMATIC DIRECTION FINDER SYSTEM

Purpose

The automatic direction finder (ADF) system is a navigation aid. The ADF receiver uses amplitude modualted (AM) signals from ground stations to calculate the bearing to the ADF station from the airplane longitudinal axis. The ADF system also receives standard AM radio broadcasts.

Abbreviations and Acronyms

· AC - alternating current

· AM - amplitude modulated

· ACP - audio control panel

· ADF - automatic direction finder

· AM - amplitude modulation

· ant - antenna

· app - approach

· ARINC - Aeronautical Radio, Inc.

· BFO - beat frequency oscillator

· Capt - captain

· DC - direct current

· DEU - display electronics unit

· EFIS - electronic flight instrument system

· F/O - first officer

· gnd - ground

· Hz - hertz

· LCD - liquid crystal display

· LRU - line replaceable unit

· nav - navigation

· NCD - no computed data

· QEC - quadrantal error correction

· RBL - right buttock line

ADF SYSTEM - GENERAL DESCRIPTION

Description

The ADF control panel supplies manual tune inputs to the ADF receiver. The ADF antenna assembly contains the loop antennas and the sense antennas.

The ADF receiver calculates the bearing to the ADF ground stations and sends it to the DEUs for display. The ADF bearing also goes to the radio magnetic indicator (RMI). The ADF receiver processes audio from the ground stations and sends it to the remote electronics unit (REU).