RADIO THEORY – Air – DGCA Question Bank For Politics

#1. Why is an X band weather radar used rather than a C band?

The C band critical ray is too small.

The C band sky ray is too weak.

C band wavelength is too long.

The C band reflected ray is too weak.

#2. What is the First returning skywave called?

The critical ray.

The B-ray.

The Wave.

The sound wave.

#3. When does the maximum fading of an HF wave occur?

When the waves are more than 90 degrees out of phase.

When the waves are 90 degrees out of phase.

When the waves are in phase.

When the waves are 180 degrees out of phase.

#4. What is the metric distance of an NDB wavelength?

Decimetric

Centmetric

Metric

Metric or Kilometric

#5. Which radio frequency employs the refraction properties of the ionosphere?

EHF.

HF.

VHF.

UHF.

#6. VOR wavelength is?

2.46 cm.

24.6 cm.

2.46 m.

24.6m

#7. VOR wavelength is?

Millimetric.

Centimetric.

Decimetric.

Metric.

#8. When is fading in the medium frequency band most likely to occur?

During the day with ground and sky waves.

During rainy days.

During the night with ground and sky waves.

During rainy nights.

#9. What is the wavelength and waveband of a radio aid that uses a frequency of 19 cm?

15.79 Hz. ELF.

15.79 Khz. VLF.

1.579 Mhz. VHF.

1.579 Ghz. UHF.

#10. Fading is greatest?

Over land during the day.

Over land at night.

Over the sea during the day.

Over the sea at night.

#11. The wavelength of a 121.95 MHz signal is?

24.6 cm.

2.46 m.

24.6 m.

2.46 km.

#12. What is skip distance?

The distance between a receiver and the first and second fundamentals.

The distance between the transmitter and the first returning skywave.

The distance between the receiver and the first returning fundamental.

The distance between the first fundamental returning to the ground, and the receiver.

#13. The skip distance is increased by .......... the wavelength and ...... the frequency?

Decreasing, decreasing.

Decreasing, increasing.

Increasing, increasing.

Increasing, decreasing.

#14. The wavelength of HF is?

Centimetric.

Decimetric.

Metric.

Kilometric.

#15. Weather radar is?

Centimetric.

Decimetric.

Metric.

Kilometric.

#16. ADF uses the.................frequency?

190 to 1750 Hz.

190 to 1750 KHz.

190 to 1750 MHz.

190 to 1750 GHz.

#17. The wavelength of VHF radio signals is?

Millimetric.

Centimetric.

Decimetric.

Metric.

#18. The wavelength of ILS is ?

Millimetric.

Centimetric.

Decimetric.

Metric.

#19. What is the wavelength of a 243 MHz radio signal.

123.4 cm.

12.34 cm.

1.234 km.

12.34 m.

#20. What is the frequency of a 95.5 cm radio wave.

3.14 MHz.

31.4 MHz.

31.4 GKz.

314 MHz.

#21. The least attenuation of a skywave is likely to occur at?

Midnight and high frequency.

Midday and high frequency.

Midnight and low frequency.

Midday and low frequency.

#22. An ELT is capable of transmitting between?

121.5 and 243 MHz for 24 hours at a temperature of -25°C.

121.5 and 243 MHz for 48 hours at a temperature of -20°C.

100 and 243 MHz for 24 hours at a temperature of -20°C.

100 and 243 MHz for 48 hours at a temperature of -25°C.

#23. Atmospheric ducting close to the earth, is most likely?

In an inversion with constant humidity at all altitudes.

In an inversion with humidity decreasing with increasing altitudes.

Over land.

Over the sea.

#24. The BFO in an ADF?

Produces a signal that differs from the received signal by approximately 2 KHz.

Produces a 2 KHz signal.

Minimise static interference.

To identify beacons when the signals are very weak.

#25. What is the frequency band and wavelength of a 4 GHz radio signal?

75 mm EHF.

7.5 cm UHF.

7.5 cm SHF.

75 cm VHF.

#26. Diffraction of radio waves?

Increases with increasing frequency.

Decreases with increasing frequency.

Is constant at all frequencies.

Varies with latitude, but not with longitude.

#27. Skywaves at day or night are least likely with?

VLF.

LF.

HF.

VHF.

#28. The optimum HF frequency puts the receiver?

Just inside the minimum skip distance.

Just outside the minimum skip distance.

Just within the surface wave coverage area.

Just outside the surface wave coverage area.

#29. Surface wave range?

Decreases with increasing frequency.

Is independent of frequency.

Decreases with decreasing frequency.

Increases with increasing amplitude.

#30. Loran operates in the ?

HF band at 300 m wavelength and 150 Khz frequency.

LF band at 3000 m wavelength and 100 Khz frequency.

VLF band at 30000 m wavelngth at 100 Hz frequency.

LF band at 3500 m wavelngth at 100 Khz frequency.

Dgca Question Bank For Pilots

Results

#1. Why is an X band weather radar used rather than a C band?

#2. What is the First returning skywave called?

#3. When does the maximum fading of an HF wave occur?

#4. What is the metric distance of an NDB wavelength?

#5. Which radio frequency employs the refraction properties of the ionosphere?

#6. VOR wavelength is?

#7. VOR wavelength is?

#8. When is fading in the medium frequency band most likely to occur?

#9. What is the wavelength and waveband of a radio aid that uses a frequency of 19 cm?

#10. Fading is greatest?

#11. The wavelength of a 121.95 MHz signal is?

#12. What is skip distance?

#13. The skip distance is increased by .......... the wavelength and ...... the frequency?

#14. The wavelength of HF is?

#15. Weather radar is?

#16. ADF uses the.................frequency?

#17. The wavelength of VHF radio signals is?

#18. The wavelength of ILS is ?

#19. What is the wavelength of a 243 MHz radio signal.

#20. What is the frequency of a 95.5 cm radio wave.

#21. The least attenuation of a skywave is likely to occur at?

#22. An ELT is capable of transmitting between?

#23. Atmospheric ducting close to the earth, is most likely?

#24. The BFO in an ADF?

#25. What is the frequency band and wavelength of a 4 GHz radio signal?

#26. Diffraction of radio waves?

#27. Skywaves at day or night are least likely with?

#28. The optimum HF frequency puts the receiver?

#29. Surface wave range?

#30. Loran operates in the ?