Question 202-1 : Which one of the following disturbances is most likely to cause the greatest inaccuracy in adf bearings ? [ Exam pilot ]

Question 202-2 : The advantage of the use of slotted antennas in modern radar technology is to ?

Virtually eliminate lateral lobes and as a consequence concentrate more energy in the main beam.

The main advantage of a slotted antenna is that it produces a much narrower beam and eliminates most of the lateral lobes therefore more energy can be concentrated in the main beam or you can use less power to transmit

Question 202-3 : The frequency which corresponds to a wavelength of 12 cm is ?

2500 mhz.

Frequency mhz = 300 wavelength m frequency mhz = 300 012 m = 2500 mhz

Question 202-4 : A cumulonimbus cloud in the vicinity of an aeroplane can cause certain navigation systems to give false indications this is particularly true of the ?

Adf.

Question 202-5 : A radio altimeter employing a continuous wave signal would have ?

A directional aerial for transmission and another one for reception.

A radio altimeter is a self contained on board aid which indicates the true height or the lowest wheels with regard to the grounda continuous wave fm radio beam in the shf band 4200 4400 mhz is directed towards the ground in a 30° cone fore and aft and 30° athwartships across the ship from side to side the signal is reflected back to the aircraftcontinuous wave as opposed to pulse radar eliminates minimum target reception range since the time delay for a pulsed signal would be too small to measure properly as well the antennae cannot switch between transmit and receive that quickly as the potential time interval is very small you need separate transmitter and receiver aerial

Question 202-6 : Which statement relating to the stabilization of airborne weather radar antennae is true ?

They are stabilized with respect to the pitch and rollaxis but not with respect to the yaw axis.

Question 202-7 : The antennae of modern airborne weather radars are stabilized by means of ?

Inputs from the aircraft's attitude system.

Automatic antenna stabilization as employed in today's weather avoidance radar systems consists of an electro mechanical means of maintaining a selected beam scan relative to the earth's horizon during moderate aircraft maneuvers to accomplish this a reference is established by the aircraft's vertical gyro usually a component of the autopilot or integrated flight control system

Question 202-8 : The type of modulation used for the ils frequency carrier is ?

Amplitude modulation.

Amplitude modulation the information that is impressed onto the carrier wave by altering the amplitude of the carrier

Question 202-9 : The quadrantal error of an adf ?

Is caused by the refraction from the aircraft's fuselage and is compensated for.

The quadrantal error is a distortion of the incoming signal from the ndb station by re radiation from the airframe this is corrected for during installation of the antenna

Question 202-10 : The skip distance of hf transmission will increase with ?

Higher frequency and higher position of the reflecting ionospheric layer.

Skip distance the distance between the transmitter and the point on the surface of the earth where the first sky return arrivesit will increase for a higher frequencyit will increase for a higher position of the reflecting ionospheric layer

Question 202-11 : Which statement about the errors and effects on ndb radio signals is correct ?

The mountain effect is caused by reflections onto steep slopes of mountainous terrain which may cause big errors in the bearing.

Mountain effect mountain areas can cause reflections and to a lesser extent diffractions and lead to the error direction reading by adfthis effect similar to night effect is obtained in mountainous areas where the energy received from an ndb consists of two or more waves one of them direct and others by reflection from the mountains bearing indications are found to change rapidly until the affected area is passedfor information night effect radio waves take two paths to the radio compass receiver the first and normal path is along the earth's surface if only these waves were received the compass would point directly to the ndb the second path is via one or more wave refracting layers above the earth the ionosphere returning to earth to mix with direct waves complete changes in the nature of the waves take place on this path and produce errors in direction

Question 202-12 : What causes the so called night effect ?

A change in the direction of the plane of polarisation due to reflection in the ionosphere.

night effect is the influence of sky waves and ground waves arriving at the adf receiver lead at a difference of phase and polarisation which introduce bearing errors at nightnight effect predominates around dusk and dawn

Question 202-13 : An amplitude modulation is shown in the figure 2069 ?

A.

Question 202-14 : In his basic type a dipole antenna adapted for a frequency of 110 mhz will have a wire of length of ?

136 cm.

Wavelength in meter = 300 frequency in mhz wavelength in meter = 300 110 = 272 m 272 cm a dipole antenna is a wire of length equal to one half of the wavelength 272 cm 2 = 136 cm

Question 202-15 : How is the unit hertz hz defined ?

The number of electromagnetic oscillations per second.

Frequency is the number of cycles occurring in one second in a radio wave expressed in hertz hz frequency is normally given in hertz hz where 1 hz = 1 cycleseconda cycle is defined as a complete series of values of a periodical process 2549

Question 202-16 : An ndb transmits on 427 khz the corresponding wavelength is ?

7025 m.

Frequency khz = speed of light wavelength m 427 khz = 300000 wavelength m wavelength m = 300000 427 = 70257 m

Question 202-17 : An electromagnetic wave consists of an oscillating electric field e and an oscillating magnetic field h their propagation speed is ?

The speed of light.

Propagation speed is the speed at which radio wave radiates through spacedepending upon the electrical nature of the medium through which it travels the speed varies slightly we can assume a constant speed of light value of 300000000 meters 162000 nm per second

Question 202-18 : The electromagnetic waves refracted from the e and f layers of the ionosphere are called ?

Sky waves.

Question 202-19 : The simplest type of antenna construction is a ?

Dipole antenna which is a wire of length equal to one half of the wavelength.

2550 dipole antenna

Question 202-20 : An electromagnetic wave consists of an oscillating electric field e and an oscillating magnetic field h which statement is correct ?

The e and h fields are perpendicular to each other.

Question 202-21 : The frequency which corresponds to a wavelength of 825 m is ?

3636 mhz.

Frequency mhz = 300 wavelength m frequency = 300 825 mfrequency = 3636 mhz

Question 202-22 : The frequency which corresponds to a wavelength of 3 km is ?

100 khz.

Frequency f in khz = 300000 wavelength m frequency f in khz = 300000 3000 m frequency f in khz = 100 khz

Question 202-23 : Wavelength of frequency 11795 mhz is ?

25 m.

Wavelength m = 300000 frequency khz wavelength m = 300 frequency mhz wavelength m = 300 11795 = 254 m

Question 202-24 : Concerning the wave propagation in the ionosphere we denote three layers those three layers are ?

D e and f layers and their depth varies with time.

2551the ionosphere is the ionized component of the earth's upper atmosphere from 60 to 400 km above the surface which is vertically structured in three regions or layers d e and f

Question 202-25 : Radio waves travel at ?

The speed of light.

Question 202-26 : In accordance with the itu international telecommunication union a radio signal may be classified by three symbols third symbol indicates eg a1a ?

Nature of information to be transmitted.

Radio signal may be classified by three symbols in accordance with the itu first symbol indicates the type of modulation of the main carrier second symbol indicates the nature of the signal modulating the main carrier third symbol indicates the nature of the information to be transmittedfor information only you do not have to know that for the exam a1a telegraphy on off keying without modulation by an audio frequencya double sideband1 single channel containing quantized or digital information without the use of a modulating sub carriera telegraphy for aural reception

Question 202-27 : In accordance with the itu international telecommunication union a radio signal may be classified by three symbols second symbol indicates eg a1a ?

Nature of signal s modulating the main carrier.

A radio signal may be classified by three symbols in accordance with the itu radio regulation volume 1 eg a1a first symbol indicates the type of modulation of the main carrier second symbol indicates the nature of the signal modulating the main carrier third symbol indicates the nature of the information to be transmitted

Question 202-28 : In accordance with the itu international telecommunication union a radio signal may be classified by three symbols first symbol indicates eg a1a ?

Type of modulation of the main carrier.

Radio signal may be classified by three symbols in accordance with the itu first symbol indicates the type of modulation of the main carrier second symbol indicates the nature of the signal modulating the main carrier third symbol indicates the nature of the information to be transmittedfor information only you do not have to know that for the exam a1a telegraphy on off keying without modulation by an audio frequencya double sideband1 single channel containing quantized or digital information without the use of a modulating sub carriera telegraphy for aural reception

Question 202-29 : Vhf very high frequency waves appear in the frequency spectrum ?

30 mhz 300 mhz.

1682

Question 202-30 : With regard to radio waves propagation a cycle is defined as ?

A complete series of values of a periodical process.

This is the official easa definition a cycle is any complete round or series of occurrences that repeats or is repeated 2549

Question 202-31 : Vlf very low frequency waves appear in the frequency spectrum ?

3 khz 30 khz.

1682

Question 202-32 : Lf low frequency waves appear in the frequency spectrum ?

30 khz 300 khz.

1682

Question 202-33 : Mf medium frequency waves appear in the frequency spectrum ?

300 khz 3000 khz.

1682

Question 202-34 : Hf high frequency waves appear in the frequency spectrum ?

3 mhz 30 mhz.

1682

Question 202-35 : Uhf ultra high frequency waves appear in the frequency spectrum ?

300 mhz 3000 mhz.

1682

Question 202-36 : Shf super high frequency waves appear in the frequency spectrum ?

3 ghz 30 ghz.

1682

Question 202-37 : Ehf extremely high frequency waves appear in the frequency spectrum ?

30 ghz 300 ghz.

1682

Question 202-38 : Frequency is defined as the ?

Number of cycles occurring in one second in a radio wave expressed in hertz hz .

A cycle is any complete round or series of occurrences that repeats or is repeated 2549the frequency is the number of cycles occurring in one second in a radio wave expressed in hertz hz

Question 202-39 : Which statement about vhfuhf frequencies is correct ?

For both vhfuhf propagation the space wave is the only propagation path of practical use there is no sky wave under normal conditions.

Radio waves in vhf uhf shf and ehf propagate as space wavesradio waves in vlf lf mf and hf propagate as surfaceground waves and sky waves

Question 202-40 : Diffraction is the process by which ?

Radio wave travel over and around obstacles.

Diffraction is the phenomenon by which wave energy bends around an object