Module 1

30問 • 2年前

問題一覧

is a marine or aircraft radio-navigation instrument that automatically and continuously displays the relative bearing from the ship or aircraft to a suitable radio station.

Automatic Direction Finder (ADF)

ADF (Automatic Direction Finder) is the radio signals in the ___________ frequency band of ____________

low to medium 190 Khz. to 1750 Khz.

The ADF can receives on both ____ radio station and ________ station.

AM NDB (Non-Directional Beacon)

is a radio transmitter at a known location, used as an aviation or marine navigational aid.

Non-Directional Beacon

NDB signals follow the ________ of the Earth.

curvature

Each NDB is identified by a one, two, or three-letter __________ callsign.

Morse code

The oldest form of radio navigation

Automatic Direction Finder

Commercial AM radio stations broadcast on _______________

540 to 1620 Khz

Non-Directional Beacon operate in the frequency band of ______________

190 to 535 Khz

ADF AND NDB EQUIPMENT (3)

ADF Indicator NDB Station Antenna

Types of ADF Indicator

Fixed Card Indicator Movable/Rotable Card Indicator Radio Magnetic Indicator

• Compass is fixed in place • Nose of the aircraft always points to a heading of 0 degree • MB= RB+ MH

Fixed Card Indicator

• The compass card canbe manually rotated • No need for calculations

Movable/Rotatable Card Indicator

• Compass card is automatically rotated by a slaved compass • The arrow will always point to current MH

Radio Magnetic Indicator

Most advanced and most efficient system

Radio Magnetic Indicator

Magnetic Heading to Radio Station

Relative Bearing

Magnetic North to Radio Station

Magnetic Bearing

2 types of Antenna in ADF

Loop Antenna Sense Antenna

The ____________ is a directional antenna that can be rotated to point in different directions. It receives the signal from the _______ station and generates a magnetic field in response.

loop antenna NDB

____________ is an omnidirectional antenna that receives the signal from all directions. It is used to provide a reference signal that helps to eliminate the effect of the aircraft's own magnetic fields on the directional information obtained from the loop antenna. The sense antenna is typically mounted on the aircraft's _________.

Sense antenna tail

It is used to provide a reference signal that helps to eliminate the effect of the aircraft's own magnetic fields on the directional information obtained from the loop antenna.

Sense Antenna

HOW ADF AND NDB WORKS?

• NDB station radiates non directional signal in all directions around its antenna • Station Identification code (Call sign) in the form of Morse Code is also transmitted by the NDB • ADF Selector in aircraft will tune to NDB's frequency in order to search its signals. After NDB call sign is identified, the direction of aircraft in bearing to the NDB station will be indicated

Filtering Device for Loop Antenna= __________ Filter device for Sense Antenna= ___________

Quadrantal Error Corrector Sense Coupler

nnagsesend ng angle kung nasan si NDB station

Goniometer

NDB/ADF Limitations

Night Effect Coastal Refraction (Shoreline effect) Interference Effect Thunderstorm Effect Mountain Effect

low signal/ no signal during night time because contamination of radio waves

Night effect

Surface wave travel in one direction over land, but another direction is over water (refraction). Can cause error reading in ADF Indicator

Coastal refraction (Shoreline effect)

interference when ADF receives two/ more NDB signals

Interference effect

very powerful discharges of static electricity that can interrupt the NDB signal

Thunderstorm effect

due to reflections/diffraction and lead to error direction

Mountain effect

MICROPROCESSOR MIDTERM MODULE 1

Annaricha Mae Dalag · 28問 · 2年前

MICROPROCESSOR MIDTERM MODULE 1