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Questions and Answers
What is the purpose of the transformer rectifier unit (TRU)?
What is the purpose of the transformer rectifier unit (TRU)?
What determines the resonant frequency of an antenna?
What determines the resonant frequency of an antenna?
What is the function of an antenna tuner in an airborne HF communication system?
What is the function of an antenna tuner in an airborne HF communication system?
What type of antenna is the Yagi antenna?
What type of antenna is the Yagi antenna?
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What layer of the ionosphere reflects HF radio waves?
What layer of the ionosphere reflects HF radio waves?
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What phenomenon can deteriorate HF communication quality?
What phenomenon can deteriorate HF communication quality?
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What is the purpose of the side tone circuit in a radio system?
What is the purpose of the side tone circuit in a radio system?
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What frequency band does the VOR operate on?
What frequency band does the VOR operate on?
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Study Notes
Radio Equipment Power
- Radio equipment requires DC power to operate.
Transformer Rectifier Unit (TRU)
- AC output of the engine driven generator is converted to DC by the TRU.
- TRU consists of a transformer, a rectifier, and a smoothing circuit.
Antenna Characteristics
- The resonant frequency of an antenna is determined by the antenna element length.
- The antenna's characteristic (resonant) frequency is electrically adjustable.
- Insertion of coils in antenna elements lowers the resonant frequency.
- Insertion of capacitors makes the resonant frequency higher.
Antenna Tuner
- Airborne HF communication system has an antenna tuner in the antenna circuit.
- The antenna tuner adjusts the resonant frequency and performs impedance matching.
Antenna Types
- Sleeve antenna, Brown antenna, and Yagi antenna are used for VHF and UHF equipment.
- Yagi antenna is a directional antenna.
Ionosphere and HF Communication
- The F layer in the ionosphere reflects HF radio waves.
- HF communication quality can be deteriorated by magnetic storm, Dellinger phenomenon, and fading depending on the strength of Sun's activity.
Radio Wave Transmission
- A carrier wave is generated by an oscillator.
- The carrier wave is modulated with a signal wave (audio), and the modulated carrier wave is amplified to the required power for transmission.
Side Tone Circuit
- The side tone circuit allows pilots to monitor their own transmission.
- Transmission signal is partially fed back to the receiving system for this purpose.
Radar Frequencies
- Detection capability of a high-frequency microwave is excellent, but its attenuation is high.
- The airport surface detection equipment (ASDE) operates on SHF (Super High Frequency).
- The air route surveillance radar (ARSR) and the airport surveillance radar (ASR) operate on UHF.
SSR Modes
- SSR mode A is capable of discriminating a "squawk" code selected on the aircraft's transponder panel.
- Mode C has a capability of automatic altitude reporting.
- Mode S is capable of addressing a single specific aircraft with its unique mode-S address.
Navigation Systems
- VOR operates on VHF, providing excellent accuracy of bearing but with limited coverage to line of sight.
- DME is commonly co-located at VOR stations to provide aircraft with bearing and distance information.
- RNAV routes are established along waypoints based on the bearing and distance information from VOR/DME.
ILS Components
- Basic ILS components are a localizer for lateral guidance, a glide slope for vertical guidance, and marker beacons for position information.
MTSAT and Satellite-Based Augmentation System
- MTSAT provided SBAS (Satellite-Based Augmentation System) for improved accuracy and reliability of GPS navigation.
- MTSAT also provided Controller Pilot Data-Link Communication (CPDLC) and Automatic Dependent Surveillance (ADS) for oceanic flights.
- SBAS function is being transferred to QSS (Quasi-Zenith Satellite System).
INMARSAT Communication
- The quality and coverage of communication by INMARSAT are much better than HF voice communication, except in polar regions.
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Description
This quiz covers the basics of radio communication, including power conversion, transformer rectifier units, and antenna properties such as resonant frequency and its electrical adjustability.