93 lines
4.1 KiB
Markdown
93 lines
4.1 KiB
Markdown
T8D – Non-voice and digital communications: image signals and definition of NTSC, CW, packet radio, PSK, APRS, error detection and correction, amateur radio networking, Digital Mobile Radio, WSJT modes, Broadband-Hamnet
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- [[T8D01]] (D)
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Which of the following is a digital communications mode? #card
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- A. Packet radio
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- B. IEEE 802.11
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- C. FT8
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- D. All these choices are correct
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- [[T8D02]] (B)
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What is a “talkgroup” on a DMR repeater? #card
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- A. A group of operators sharing common interests
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- B. A way for groups of users to share a channel at different times without hearing other users on the channel
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- C. A protocol that increases the signal-to-noise ratio when multiple repeaters are linked together
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- D. A net that meets at a specified time
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- [[T8D03]] (D)
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What kind of data can be transmitted by APRS? #card
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- A. GPS position data
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- B. Text messages
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- C. Weather data
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- D. All these choices are correct
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- [[T8D04]] (C)
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What type of transmission is indicated by the term "NTSC?"
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- A. A Normal Transmission mode in Static Circuit
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- B. A special mode for satellite uplink
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- C. An analog fast-scan color TV signal
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- D. A frame compression scheme for TV signals
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- [[T8D05]] (A)
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Which of the following is an application of APRS? #card
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- A. Providing real-time tactical digital communications in conjunction with a map showing the locations of stations
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- B. Showing automatically the number of packets transmitted via PACTOR during a specific time interval
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- C. Providing voice over internet connection between repeaters
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- D. Providing information on the number of stations signed into a repeater
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- [[T8D06]] (B)
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What does the abbreviation "PSK" mean? #card
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- A. Pulse Shift Keying
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- B. Phase Shift Keying
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- C. Packet Short Keying
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- D. Phased Slide Keying
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- [[T8D07]] (A)
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Which of the following describes DMR? #card
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- A. A technique for time-multiplexing two digital voice signals on a single 12.5 kHz repeater channel
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- B. An automatic position tracking mode for FM mobiles communicating through repeaters
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- C. An automatic computer logging technique for hands-off logging when communicating while operating a vehicle
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- D. A digital technique for transmitting on two repeater inputs simultaneously for automatic error correction
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- [[T8D08]] (D)
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Which of the following is included in packet radio transmissions? #card
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- A. A check sum that permits error detection
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- B. A header that contains the call sign of the station to which the information is being sent
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- C. Automatic repeat request in case of error
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- D. All these choices are correct
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- [[T8D09]] (D)
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What is CW? #card
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- A. A type of electromagnetic propagation
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- B. A digital mode used primarily on 2 meter FM
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- C. A technique for coil winding
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- D. Another name for a Morse code transmission
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- [[T8D10]] (D)
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Which of the following operating activities is supported by digital mode software in the WSJT-X software suite?
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- A. Earth-Moon-Earth
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- B. Weak signal propagation beacons
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- C. Meteor scatter
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- D. All these choices are correct
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- [[T8D11]] (C)
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What is an ARQ transmission system? #card
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- A. A special transmission format limited to video signals
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- B. A system used to encrypt command signals to an amateur radio satellite
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- C. An error correction method in which the receiving station detects errors and sends a request for retransmission
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- D. A method of compressing data using autonomous reiterative Q codes prior to final encoding
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- [[T8D12]] (A)
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Which of the following best describes an amateur radio mesh network? #card
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- A. An amateur-radio based data network using commercial Wi-Fi equipment with modified firmware
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- B. A wide-bandwidth digital voice mode employing DMR protocols
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- C. A satellite communications network using modified commercial satellite TV hardware
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- D. An internet linking protocol used to network repeaters
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- [[T8D13]] (B)
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What is FT8? #card
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- A. A wideband FM voice mode
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- B. A digital mode capable of low signal-to-noise operation
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- C. An eight channel multiplex mode for FM repeaters
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- D. A digital slow-scan TV mode with forward error correction and automatic color compensation
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