Vayudoot Aviation

1. Complete the following statement. .....radio signals have a ..... range by ..... wave over ..... than over .....?

MF, shorter, sky, sea, land.

MF, greater, ground, land, sea.

VHF, shorter, sky, sea, land.

MF, greater, ground, sea, land.

2. The frequency at which sky waves should least affect reception?

HF

LF.

VLF.

MF.

3. What is the wavelength corresponding to a frequency of 75 MHz?

7.5 metres.

40 metres.

75 metres.

4 metres.

4. Attenuation of a radio wave is the?

Increase of its power by the combination of multi-path signals.

Change of amplitude by use of sidebands.

Reduction of its power by absorption, scattering or spreading.

Change of its frequency by use of sidebands.

5. The wavelength of a radio signal is 200 metres. What is its frequency?

1.5 kHz.

15 MHz.

1.5 MHz.

1.5 GHz.

6. According to ICAO Annex 10, in which frequency band(s) does a locator transmit?

HF/VHF

HF

LF/MF

MF/HF

7. Comparing a parabolic reflector with a flat plate antenna of the same size?

The flat plate antenna generates less side lobes than the parabolic reflector

The flat plate has a considerably smaller beam width

The parabolic reflector generates less side lobes that the flat plate antenna.

The parabolic reflector has a considerably smaller beam width

8. Feeder lines are of the following types?

Co-axial-up to 300 kHz, wave guides- above 300 kHz.

Co-axial- above 3000 MHz, wave guides- up to 3000 MHz.

Co-axial-up to 3000 MHz, wave guides- above 3000 MHz.

Wave guides - up to 20 MHz, co-axial-above 20 MHz.

9. Reflection from the ionospheric layers is used in the following radio frequencies?

HF.

VHF.

VLF.

UHF.

10.
At night due to the reception of both sky waves and ground waves.

Increase over the sea.

Increase.

Decrease.

Decrease by night only.

11. A Doppler shift will occur?

When the distance between a transmitter and a receiver is changing during a transmission.

If a transmitter is moving during transmission to a fixed position.

All of the options are correct.

If a receiver is moving during reception of transmission from a fixed position transmitter.

12.
In the diagram below what is the phase difference of the higher amplitude signal from the reference signal?

225 degrees

315 degrees

045 degrees.

135 degrees.

13. A radio signal has a frequency of 3 GHz, What is its wavelength?

1.0 centimetres.

10 centimetres.

1 metres

100 centimetres.

14. A radio signal loses strength as the range from the transmitter increases. This effect is called?

Ducting.

Attenuation.

Refraction.

Amplification.

15. Assuming a frequency of 20 MHz, the wavelength will be?

1.25 metres.

80 metres

800 metres

12.5 metres

16. A transmission of RF energy at a wavelength of 18 metres is in which frequency band?

VHF

MF

HF

LF

17. A radio wave with a horizontal magnetic component would be best received by a ......... aerial?

Vertical

Magnetic

Parabolic

Horizontal

18. Fading happens?

At daytime when the signal is received by sky waves only.

At night when the signal is received by ground waves only.

In daytime when ground waves and sky waves interfere with each other.

At night when ground waves and sky waves interfere with each other.

19. What is the lowest frequency where freedom from static interference can be guaranteed?

300 MHz.

30 MHz.

3 GHz.

3 MHz.

20. Skip distance is longest by ..... and with a ..... frequency?

Day, low.

Day, high.

Night, high.

Night, low.

21. The wavelength of a non-directional beacon (NDB) at a frequency of 300 kHz is?

1 metres

100 metres

10 metres

1000 metres

22. The emission characteristics A3E describe?

VHF communications

ILS

HF communications

VOR

23. What is the wavelength of the ILS Localiser signal?

Centimetric

Metric

Hectometric

Myriametric

24. The VHF Direction Finder uses the following wavelengths?

Decimetric

Metric

Centimetric

Hectometric

25. When an LF radio wave passes over the Earth's surface it?

Slows down and is attenuated.

Speeds up, picks up electrons and becomes stronger.

Slows down, picks up electrons and becomes stronger.

Speeds up and is attenuated.

26. The VHF Omnirange (VOR) uses the following wavelengths?

Centimetric

Hectometric

Metric

Decimetric

27. A horizontally polarised electromagnetic wave?

Has the H field horizontal.

Has the E field vertical

Has the Z field horizontal

Has the E field horizontal.

28. What is the frequency corresponding to a wavelength of 12 centimetres is?

360 MHz.

2500MHz.

3600 MHz.

2500 kHz

29. A half wave dipole aerial suitable for transmitting an RF signal at 18 MHz should have an effective length of?

83.33 metres

166.67 metres.

8.33 metres

16.67 metres.

30. What is the wavelength of a radio signal with a frequency of 375 kHz?

1.25 metres

12.5 metres

800 metres

80 metres

31. A radio facility transmits on a wavelength of 2.22 cm. The facility could be a ............. operating on a frequency of ........?

DME, 1350 MHz.

Doppler 13500 MHz.

VDF, 135 MHz.

Radio Altimeter 13500 kHz.

32. The Secondary Surveillance Radar (SSR) uses the following wavelengths?

Decimetric

Centimetric

Hectometric

Myriametric

33. Refraction of an eletromagnetic radiation is?

The bending of its propagation path as it passes through or over areas of different electrical conductivity.

The loss of power as it passes through or over areas of different electrical conductivity.

Bending resultant from reflection from objects.

Loss of power through reflection from objects.

34. An aircraft travelling at 300 metres per second transmits a radio signal at 10 GHz to a stationary receiver. If the aircraft is flying directly towards the receiver and they are approximately at the same height, the received signal frequency will be?

9.999989 GHz.

10.000011 GHz.

11 GHz.

11 MHz.

35. The VHF frequency band is in the?

3 to 30 kHz range.

30 to 300 MHz range.

30 to 300 kHz range.

3 to 30 MHz range

36. In the propagation of MF waves, the phenomenon of FADING is particularly found?

At night and when raining.

At night, due to the combination of sky waves and ground waves.

By day and when raining.

By day due to the combination of sky waves and ground waves.

37. SELCAL is an equipment that?

Functions as a frequency modulator.

Automatically receives incoming signals

Automatically transmits data signals.

Is coupled with TCAS II and is concerned with TA warnings systems.

38. In regard to radio what does the term frequency mean?

The speed of radio waves in metres per second

The number of waveform in one hour.

The number of complete waveform passing a point in one second

The length of a complete waveform in metres.

39. The Marker beacons use the following wavelengths?

Hectometric

Metric

Myriametric

Centimetric

40. Attenuation of radio waves means?

Only the scattering of waves in the troposphere.

Only the absorption of energy by the sea.

The atmospheric bending of waves.

The weakening of radiated waves.

41. The wavelength of a radio signal with a frequency of 121.95 MHz?

2.46 metres.

24.60 centimetres

2.46 centimetres

26.60 metres.

42. Into what range does ILS localiser wavelength fall?

Millimetric

Metric

Nanometric

Kilometric

43. A radio transmitter modulator?

Superimposes an audio frequency signal (AF) onto a radio frequency signal (RF).

Ensures receiver compatibility

Couples the RF signal to an aerial

Tunes the aerial only

44. Decimetric waves correspond to a frequency of?

3000 to 30000 MHz.

3000 to 30000 kHz.

300 to 3000 kHz.

300 to 3000 MHz.

45. The distance Measuring Equipment (DME) uses the following wavelengths?

Metric

Centimetric

Hectometric

Decimetric

46. A wavelength of 8.5 metres corresponds to a frequency of?

2833.3 MHz.

28333 MHz.

3594.4 MHz.

35294 MHz.

47. MF fading is most common?

At night due to the reception of both sky waves and ground waves.

During the day due to the reception of both sky waves and ground waves.

At night and during heavy rain.

During the day and during heavy rain.

48. To establish and maintain effective HF communication, frequency at a given range?

Should only be varied by season, decreased in summer and increased in winter.

Should be decreased at night.

Should be increased at night.

Should remain constant.

49. What is the wavelength of a VOR?

Hectometric

Decimetric

Metric

Centimetric

50. Diffraction is the process by which?

A ground wave is attenuated over rough ground.

A direct wave is bend around the form of the Earth.

Radio waves travel over and around objects.

A space wave penetrates the ionosphere.

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