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 

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