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Technician exam T8: Modulation and Signals

All 47 questions in subelement T8. The exam asks 4 of them, one from each group (T8A, T8B, T8C, T8D). Answers are hidden until you open them.

Drill these 47 questions Full practice exam

T8A

  1. T8A01 Which of the following is a form of amplitude modulation?

    1. Spread spectrum
    2. Packet radio
    3. Single sideband
    4. Phase shift keying (PSK)
    Show answer

    C. Single sideband

  2. T8A02 What type of modulation is commonly used for VHF packet radio transmissions?

    1. FM or PM
    2. SSB
    3. AM
    4. PSK
    Show answer

    A. FM or PM

  3. T8A03 Which type of voice mode is often used for long-distance (weak signal) contacts on the VHF and UHF bands?

    1. FM
    2. DRM
    3. SSB
    4. PM
    Show answer

    C. SSB

  4. T8A04 Which type of modulation is commonly used for VHF and UHF voice repeaters?

    1. AM
    2. SSB
    3. PSK
    4. FM or PM
    Show answer

    D. FM or PM

  5. T8A05 Which of the following signal types has the narrowest bandwidth?

    1. FM voice
    2. SSB voice
    3. CW
    4. Slow-scan TV
    Show answer

    C. CW

  6. T8A06 Which sideband is normally used for 10-meter HF, VHF, and UHF single-sideband communications?

    1. Upper sideband
    2. Lower sideband
    3. Suppressed sideband
    4. Inverted sideband
    Show answer

    A. Upper sideband

  7. T8A07 What is one characteristic of single sideband (SSB) compared to FM?

    1. SSB signals are easier to tune in correctly
    2. SSB signals are less susceptible to interference
    3. SSB signals have narrower bandwidth
    4. SSB signals are less susceptible to high SWR
    Show answer

    C. SSB signals have narrower bandwidth

  8. T8A08 What is the approximate bandwidth of a typical single sideband (SSB) voice signal?

    1. 1 kHz
    2. 3 kHz
    3. 6 kHz
    4. 15 kHz
    Show answer

    B. 3 kHz

  9. T8A09 What is the approximate bandwidth of an FM voice signal on VHF repeaters?

    1. Less than 500 Hz
    2. About 150 kHz
    3. Between 10 and 15 kHz
    4. Between 50 and 125 kHz
    Show answer

    C. Between 10 and 15 kHz

  10. T8A10 What is the approximate bandwidth of AM fast-scan TV transmissions?

    1. More than 10 MHz
    2. About 6 MHz
    3. About 3 MHz
    4. About 1 MHz
    Show answer

    B. About 6 MHz

  11. T8A11 What is the approximate bandwidth required to transmit a CW signal?

    1. 2.4 kHz
    2. 150 Hz
    3. 1000 Hz
    4. 15 kHz
    Show answer

    B. 150 Hz

  12. T8A12 Which of the following is a disadvantage of FM compared with single sideband?

    1. Voice quality is poorer
    2. Only one signal can be received at a time
    3. FM signals are harder to tune
    4. FM signals are more susceptible to high SWR
    Show answer

    B. Only one signal can be received at a time

T8B

  1. T8B01 What telemetry information is typically transmitted by satellite beacons?

    1. The signal strength of received signals
    2. Time of day accurate to plus or minus 1/10 second
    3. Health and status of the satellite
    4. All these choices are correct
    Show answer

    C. Health and status of the satellite

  2. T8B02 What is the impact of using excessive effective radiated power on a satellite uplink?

    1. Possibility of commanding the satellite to an improper mode
    2. Blocking access by other users
    3. Overloading the satellite batteries
    4. Possibility of rebooting the satellite control computer
    Show answer

    B. Blocking access by other users

  3. T8B03 Which of the following are provided by satellite tracking programs?

    1. Maps showing the real-time position of the satellite track over Earth
    2. The time, azimuth, and elevation of the start, maximum altitude, and end of a pass
    3. The apparent frequency of the satellite transmission, including effects of Doppler shift
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  4. T8B04 What mode of transmission is commonly used by amateur radio satellites?

    1. SSB
    2. FM
    3. CW/data
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  5. T8B05 What is a satellite beacon?

    1. The primary transmit antenna on the satellite
    2. An indicator light that shows where to point your antenna
    3. A reflective surface on the satellite
    4. A transmission from a satellite that contains status information
    Show answer

    D. A transmission from a satellite that contains status information

  6. T8B06 Which of the following are inputs to a satellite tracking program?

    1. The satellite transmitted power
    2. The Keplerian elements
    3. The last observed time of zero Doppler shift
    4. All these choices are correct
    Show answer

    B. The Keplerian elements

  7. T8B07 What is Doppler shift in reference to satellite communications?

    1. A change in the satellite orbit
    2. A mode where the satellite receives signals on one band and transmits on another
    3. An observed change in signal frequency caused by relative motion between the satellite and Earth station
    4. A special digital communications mode for some satellites
    Show answer

    C. An observed change in signal frequency caused by relative motion between the satellite and Earth station

  8. T8B08 What does it mean if a satellite is operating in U/V mode?

    1. The satellite uplink is in the 15-meter band and the downlink is in the 10-meter band
    2. The satellite uplink is in the 70-centimeter band and the downlink is in the 2-meter band
    3. The satellite operates using ultraviolet frequencies
    4. The satellite frequencies are usually variable
    Show answer

    B. The satellite uplink is in the 70-centimeter band and the downlink is in the 2-meter band

  9. T8B09 What causes spin fading of satellite signals?

    1. Circular polarized noise interference radiated from the sun
    2. Rotation of the satellite and its antennas
    3. Doppler shift of the received signal
    4. Interfering signals within the satellite uplink band
    Show answer

    B. Rotation of the satellite and its antennas

  10. T8B10 What does the term LEO mean in reference to communication satellites?

    1. Low Energy Orbit, which conserves battery power
    2. Low Elevation Orbit, which appears close to the horizon from the earth station
    3. Low Equilibrium Orbit, which has a slightly unstable period
    4. Low Earth Orbit, which has a period of around 100 minutes
    Show answer

    D. Low Earth Orbit, which has a period of around 100 minutes

  11. T8B11 Who is permitted to receive telemetry from an amateur radio satellite?

    1. Anyone
    2. Only the satellite control operator
    3. Only the control operator or a licensed radio amateur who has received the encryption key from the control operator
    4. Only a licensed radio amateur who has received the encryption key from AMSAT
    Show answer

    A. Anyone

  12. T8B12 Which of the following is a way to determine whether your satellite uplink power into a linear transponder satellite is neither too low nor too high?

    1. Check your signal strength report in the telemetry data
    2. Listen for distortion on your downlink signal
    3. Your signal strength on the downlink should be about the same as the beacon
    4. Compare your signal to others on the downlink using an internet SDR receiver
    Show answer

    C. Your signal strength on the downlink should be about the same as the beacon

T8C

  1. T8C01 Which of the following methods is used to locate sources of noise interference or jamming?

    1. Echolocation
    2. Doppler radar
    3. Radio direction finding
    4. Phase locking
    Show answer

    C. Radio direction finding

  2. T8C02 Which of these items would be useful for a hidden transmitter hunt?

    1. Calibrated SWR meter
    2. A directional antenna
    3. A directional wattmeter
    4. All these choices are correct
    Show answer

    B. A directional antenna

  3. T8C03 What operating activity involves contacting as many stations as possible during a specified period?

    1. Simulated emergency exercises
    2. Net operations
    3. Hidden transmitter hunts
    4. Contesting
    Show answer

    D. Contesting

  4. T8C04 Which of the following is good practice when contacting another station in a contest?

    1. Signing only the last two letters of your call if there are many other stations calling
    2. Contacting the station twice to be sure that you are in his log
    3. Sending only the minimum information needed for proper identification and the contest exchange
    4. Adding “Please copy” before your exchange
    Show answer

    C. Sending only the minimum information needed for proper identification and the contest exchange

  5. T8C05 What is a grid locator?

    1. A letter-number designator assigned to a geographic location
    2. A letter-number designator assigned to an azimuth and elevation
    3. An instrument for locating faults in power amplifiers
    4. An instrument for radio direction finding
    Show answer

    A. A letter-number designator assigned to a geographic location

  6. T8C06 How is over the air access to Internet Radio Linking Project (IRLP) nodes accomplished?

    1. By obtaining a password that is sent via voice to the node
    2. By using Dual-Tone Multi-Frequency (DTMF) signals
    3. By entering the proper internet password
    4. By using Continuous Tone-Coded Squelch System (CTCSS) tone codes
    Show answer

    B. By using Dual-Tone Multi-Frequency (DTMF) signals

  7. T8C07 What is Voice Over Internet Protocol (VoIP)?

    1. A set of rules specifying how to identify your station when linked over the internet to another station
    2. A technique employed to “spot” DX stations via the internet
    3. A technique for measuring the modulation quality of a transmitter using remote sites monitored via the internet
    4. A method of delivering voice communications over the internet using digital techniques
    Show answer

    D. A method of delivering voice communications over the internet using digital techniques

  8. T8C08 What is the Internet Radio Linking Project (IRLP)?

    1. A technique to connect amateur radio systems, such as repeaters, via the internet
    2. A system for providing access to websites via amateur radio
    3. A system for informing amateurs in real time of the frequency of active DX stations
    4. A technique for measuring signal strength of an amateur transmitter via the internet
    Show answer

    A. A technique to connect amateur radio systems, such as repeaters, via the internet

  9. T8C09 Which of the following protocols enables an amateur station to transmit through a repeater without using a radio to initiate the transmission?

    1. IRLP
    2. D-STAR
    3. DMR
    4. EchoLink
    Show answer

    D. EchoLink

  10. T8C10 What is required before using the EchoLink system?

    1. Complete the required EchoLink training
    2. Purchase a license to use the EchoLink software
    3. Register your call sign and provide proof of license
    4. At least a General Class license
    Show answer

    C. Register your call sign and provide proof of license

  11. T8C11 What is an amateur radio station that connects other amateur stations to the internet?

    1. A gateway
    2. A repeater
    3. A digipeater
    4. A beacon
    Show answer

    A. A gateway

T8D

  1. T8D01 Which of the following is a digital communications mode?

    1. Packet radio
    2. IEEE 802.11
    3. FT8
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  2. T8D02 What is FT8?

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

    B. A digital mode capable of low signal-to-noise operation

  3. T8D03 What kind of data can be transmitted by APRS?

    1. GPS position data
    2. Text messages
    3. Weather data
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  4. T8D04 What is meant by the term "NTSC?"

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

    C. An analog fast-scan color TV signal

  5. T8D05 Which of the following is an application of APRS?

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

    A. Providing real-time tactical digital communications in conjunction with a map showing the locations of stations

  6. T8D06 What does the abbreviation "PSK" mean?

    1. Pulse Shift Keying
    2. Phase Shift Keying
    3. Packet Sampled Keying
    4. Power Sampled Keying
    Show answer

    B. Phase Shift Keying

  7. T8D07 Which of the following describes DMR?

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

    A. A technique for time-multiplexing two digital voice signals on a single 12.5 kHz repeater channel

  8. T8D08 Which of the following is included in packet radio transmissions?

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

    D. All these choices are correct

  9. T8D09 What is CW?

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

    D. Another name for a Morse code transmission

  10. T8D10 Which of the following operating activities is supported by digital mode software in the WSJT-X software suite?

    1. Earth-Moon-Earth
    2. Weak signal propagation beacons
    3. Meteor scatter
    4. All these choices are correct
    Show answer

    D. All these choices are correct

  11. T8D11 What is the role of ARQ in a transmission system?

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

    C. An error correction method in which the receiving station detects errors and sends a request for retransmission

  12. T8D12 Which of the following best describes an amateur radio mesh network?

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

    A. An amateur-radio data network using commercial Wi-Fi equipment with modified firmware

Questions: NCVEC Question Pool Committee (public domain). Pool valid July 1, 2026 – June 30, 2030.