Which of the following is a digital communications mode?

1. A Packet radio
2. B IEEE 802.11
3. C FT8
4. D All these choices are correct

What is FT8?

1. A A wideband FM voice mode
2. B A digital mode capable of low signal-to-noise operation
3. C An eight-channel multiplex mode for FM repeaters
4. D A digital slow-scan TV mode with forward error correction and automatic color compensation

What kind of data can be transmitted by APRS?

1. A GPS position data
2. B Text messages
3. C Weather data
4. D All these choices are correct

What is meant by the term "NTSC?"

1. A A digital transmission standard for encrypting data
2. B A special mode for satellite uplink
3. C An analog fast-scan color TV signal
4. D A frame compression scheme for TV signals

Which of the following is an application of APRS?

1. A Providing real-time tactical digital communications in conjunction with a map showing the locations of stations
2. B Automatically showing the number of packets transmitted via PACTOR during a specific time interval
3. C Providing voice over internet connection between repeaters
4. D Providing information on the number of stations signed into a repeater

What does the abbreviation "PSK" mean?

1. A Pulse Shift Keying
2. B Phase Shift Keying
3. C Packet Sampled Keying
4. D Power Sampled Keying

Which of the following describes DMR?

1. A A technique for time-multiplexing two digital voice signals on a single 12.5 kHz repeater channel
2. B An automatic position tracking mode for FM mobiles communicating through repeaters
3. C An automatic computer logging technique for hands-off logging when communicating while operating a vehicle
4. D A digital technique for transmitting on two repeater inputs simultaneously for automatic error correction

Which of the following is included in packet radio transmissions?

1. A A checksum that permits error detection
2. B A header that contains the call sign of the station to which the information is being sent
3. C Automatic repeat request in case of error
4. D All these choices are correct

What is CW?

1. A A type of electromagnetic propagation
2. B A digital mode used primarily on 2-meter FM
3. C Error correction for digital transmission using code words
4. D Another name for a Morse code transmission

Which of the following operating activities is supported by digital mode software in the WSJT-X software suite?

1. A Earth-Moon-Earth
2. B Weak signal propagation beacons
3. C Meteor scatter
4. D All these choices are correct

What is the role of ARQ in a transmission system?

1. A A special transmission format limited to video signals
2. B A system used to encrypt command signals to an amateur radio satellite
3. C An error correction method in which the receiving station detects errors and sends a request for retransmission
4. D A method of compressing data using autonomous reiterative Q codes prior to final encoding

Which of the following best describes an amateur radio mesh network?

1. A An amateur-radio data network using commercial Wi-Fi equipment with modified firmware
2. B A wide-bandwidth digital voice mode employing DMR protocols
3. C An amateur-radio satellite communications network using modified commercial satellite TV hardware
4. D An internet linking protocol allowing communication through repeaters around the world