What is the frequency in which the DME transmits?

Aeronautical & Aerospace Engineering : Avionics - Quiz(MCQ)

20Mhz above the received frequency

40Mhz below the received frequency

50Mhz above or below the received frequency

63Mhz above or below the received frequency

Correct Answer : 63Mhz above or below the received frequency

Explanation : The Ground beacon in the DME receives the airborne pulses, and after a 50μs delay, retransmits them back to the aircraft on a frequency 63Mhz above or below the airborne transmitting frequency. Here the frequency received by the DME is the Airborne transmitting frequency.

Recently Updated in Avionics Questions

Which of the following type is not used in an Omega system?

Valley span

Insulated tower

Hanging tower

Grounded tower

Correct Answer : Option (C) : Hanging tower

Explanation : Since the Omega stations transmit in very low frequencies, the antennas are the largest physical structures in the stations. Three types of antennas are employed in the Omega system: grounded tower, insulated tower, and the valley span.

_____ acts as a coarse tuning device for the antenna?

Loop

Helix

Filters

Amplifiers

Correct Answer : Option (B) : Helix

Explanation : The RF signal that is to be transmitted is transferred to the ‘Helix,’ a large helical coil that acts as a coarse tuning device for the antenna. The helix is equipped with separate taps for each signal frequency transmitted.

What type of transmission is used in Omega system?

Phase modulated wave

Continuous wave

Amplitude modulated wave

Frequency modulated wave

Correct Answer : Option (B) : Continuous wave

Explanation : At each Omega station, continuous wave signals on four common frequencies and one station unique frequency. The signal frequencies are time shared among the stations so that a given frequency is transmitted by only one station at any given time.