Speech Frequency Ranges

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What is the minimum frequency range required for the transmission of speech?

500 Hz to 2000 Hz (correct)

250 Hz to 2750 Hz

200 Hz to 4000 Hz

300 Hz to 3 kHz

Why is it not practical to transmit human voice frequencies via radio circuits?

Because of the low power consumption

Because of the extremely long wavelengths (correct)

Because of the high antenna dimensions

Because of the high frequency range

What is the typical range of radiating elements in antennas?

1/10, 1/5, 1/2, or more full wavelengths

1/8, 1/4, 1/2, or more full wavelengths

1/2, 1, 2, or more full wavelengths

1/4, 1/2, 1, or more full wavelengths (correct)

What is the process called that impresses the voice signal onto a radiofrequency wave?

Modulation Signup and view all the answers

Why is a carrier wave used in radiotelephone circuits?

To have a wavelength short enough to be radiated from an antenna of practical dimensions Signup and view all the answers

What is the wavelength of the frequency 250 Hz on radiotelephone circuits?

1 200 000 meters Signup and view all the answers

What is the primary factor that affects the range of HF communications?

Frequency selected and time of day Signup and view all the answers

Why do HF transmitters produce a higher output power compared to VHF transmitters?

To achieve longer communication ranges Signup and view all the answers

What is the primary reason why jet aircraft rarely have long wire HF antennas?

Vibration and increased risk of damage at high speeds Signup and view all the answers

Why do long wire antennas on light aircraft have a weak point?

To prevent the antenna from wrapping around the aircraft and causing damage Signup and view all the answers

What is the maximum range of VHF communications?

About 400 km (air to ground) Signup and view all the answers

Why do aircraft sometimes lose communication over the middle of an ocean?

Due to atmospheric interference from thunderstorms Signup and view all the answers

What is the primary purpose of the ARINC Control and Reporting System (ACARS) in aircraft operations?

To reduce reliance on voice communications for routine information transmission Signup and view all the answers

What system is used by the aircraft to transmit data to the Airline Operations Controllers (AOC) facilities?

VHF radio system Signup and view all the answers

What is the purpose of the ACARS computer on the aircraft?

To receive and demodulate the ACARS encoded data from the VHF radio system Signup and view all the answers

What is the benefit of using ACARS in terms of aircraft turnaround planning?

It enables more efficient planning of logistics support Signup and view all the answers

What type of information is typically transmitted between the aircraft and Airline Operations Controllers (AOC) using ACARS?

Routine information such as aircraft status and logistics requirements Signup and view all the answers

What organization developed and implemented the ARINC Control and Reporting System (ACARS)?

Aeronautical Radio Incorporated (ARINC) Signup and view all the answers

What happens to the receiver function when the push-to-transmit button is pressed?

It is replaced by the transmitter function Signup and view all the answers

Why are two separate receiver/transmitter systems required for full duplex transmission?

To allow simultaneous transmission and reception Signup and view all the answers

What is a characteristic of radio transmissions?

They can be received by any radio receiver within the broadcast area Signup and view all the answers

What is the function of the radio control panel?

To interface system components and control radio system functions Signup and view all the answers

What is normally remotely located on the control column?

The press-to-transmit button Signup and view all the answers

What is displayed on the radio control panel?

The carrier frequency being modulated by the audio Signup and view all the answers

What is the primary function of the Management Unit in an ACARS system?

To control the transmission and reception of air-to-ground and ground-to-air messages Signup and view all the answers

What type of signal is formatted by the Management Unit for transmission to the ground?

Digital Signup and view all the answers

What is the purpose of the Control Unit in an ACARS system?

To allow the flight crew to enter information into the data link system Signup and view all the answers

What type of messages are typically printed out by the printer in an ACARS system?

Weather reports and dispatch messages Signup and view all the answers

What is the term for the radio transmission path upward from the earth to the aircraft?

Uplink Signup and view all the answers

What triggers the Management Unit to collect data from the Control Unit and various aircraft systems?

Clearing the gate and being ready to taxi Signup and view all the answers