12 COVERAGE - IF AT MRA, 50 NM - RECEPTION DISTANCE IS 1.23 x √ ALTITUDE
13 PRINCIPLES OF OPERATION Operation of the VOR is based on a phase difference between two signals – a reference phase and a variable phase. The reference phase, which is omni directional, radiates from the station in a circular pattern, the phase being constant throughout 360 degrees. The variable phase rotates uniformly at 1800 rpm causing its phase to vary at a constant rate.
14 Magnetic North is the reference datum for measuring the phase difference between the two signals. At Magnetic North, the two signals are exactly in phase. At other points around the compass, the phase difference varies accordingly. The aircraft equipment resolves the phase difference and displays it primarily in the form of angular displacement from Magnetic North as measured from the VOR station.
21 VOR RELIABILITYAt the VOR facility, a monitoring system and two transmitters insure continuous reliable service. If the VOR signal is interrupted or the phasing is changed, the monitor system turns off defective equipment, turns on the stand-by transmitter, and excites an alarm at the remote control station. When a VOR is “on the air” while servicing is taking place, the station identification is removed.
25 ADF – Automatic Direction Finder Receiver tune and identifyLF/MF 2 or 3 letter Morse codeILS locator 1 letter Morse codeSignal also powers bearing indicatorAntennaeLoop senses direction of stationSense provides info if bearing to or from stationBearing indicatorPoints to station relative to nose or axisFixed card 0o is nose and 180o is tail
26 ADF FUNCTIONS AIRWAYS AIR ROUTES ILS LOCATORS – MARKER BEACONS MARINE BEACONSNDB APPROACHESCOMMERCIAL BROADCAST
28 ADF LIMITATIONS TWILIGHT EFFECT TERRAIN or MOUNTAIN EFFECT JUST BEFORE/AFTER SUNSET/SUNRISE - fly highGREATER AT GREAT DISTANCE – use less than 350 khzTERRAIN or MOUNTAIN EFFECTSHORELINE – signals crossing at less than 30oELECTRICAL STORMSBANK ERROR – ALL TURNSLOOP ANTENNAE ROTATES TO SENSE DIRECTION OF INCOMING SIGNAL AND IS MOUNTED PARALLEL TO NORMAL AXIS
29 ADF ADVANTAGES LOW COST INSTALLATION AND MAINTENANCE NOT LINE OF LINE OF SIGHT SO GIVES GREATER RECEPTION AT LOWER ALTITUDES THAN VORPRIMARY NAVIGATION OVER LONG DISTANCE IN REMOTE AREAS
30 TRACKING TO THE STATION PARALLEL TRACKDESIRED TO HEADDETERMINES THE TURNLEFT TURNDESIRED TRACK – INTERCEPT ANGLE = INTERCEPT HEADINGRIGHT TURNDESIRED TRACK + INTERCEPT ANGLE = INTERCEPT HEADING
31 TRACKING FROM THE STATION PARALLEL TRACKTAIL TO DESIREDDETERMINES THE TURNLEFT TURNDESIRED TRACK – INTERCEPT ANGLE = INTERCEPT HEADINGRIGHT TURNDESIRED TRACK + INTERCEPT ANGLE = INTERCEPT HEADING
32 SOME RULESWHEN INTERCEPTING A TRACK TO OR FROM A STATION, BEARING INDICATOR ALWAYS AWAYFROM 0 OR TOWARDS 1802. WHEN TURNING, IF HEADING INDICATOR INCREASES, THEN ADF BEARINGINDICATOR (VALUE) DECREASESHI LESS, ADF MOREWHEN TRACKING, NEEDLE RIGHT? YES, THEN WIND IS FROM THE RIGHT SO TURN RIGHT, ETC.MAGNETIC HEADING + RELATIVE BEARING = MAGNETIC BEARING TO THE STATIONMH + RB = MB TO THE STATIONMH = MB – RBRB = MB - MH