All 47 Ham Radio Technician questions for T8 Modulation & Signals with the correct answers marked and a short explanation for each, from the official 2026-2030 question pool. Test yourself with the free practice exam.
T8A01
Which of the following is a form of amplitude modulation?
A. Spread spectrum
B. Packet radio
C. Single sideband ✓
D. Phase shift keying (PSK)
Why: Single sideband (SSB) is a form of amplitude modulation in which the carrier and one sideband are removed, leaving only one sideband. Packet and PSK are digital modes, and spread spectrum is a different technique.
T8A02
What type of modulation is commonly used for VHF packet radio transmissions?
A. FM or PM ✓
B. SSB
C. AM
D. PSK
Why: VHF packet radio typically sends audio tones (AFSK) through an ordinary FM or PM transceiver, usually at 1200 baud. SSB and PSK are more common on HF.
T8A03
Which type of voice mode is often used for long-distance (weak signal) contacts on the VHF and UHF bands?
A. FM
B. DRM
C. SSB ✓
D. PM
Why: SSB is favored for weak-signal VHF/UHF work because all its power goes into a narrow signal, giving better range than FM for weak signals. FM is used mostly for local and repeater contacts.
T8A04
Which type of modulation is commonly used for VHF and UHF voice repeaters?
A. AM
B. SSB
C. PSK
D. FM or PM ✓
Why: VHF and UHF voice repeaters use FM or the closely related phase modulation (PM). FM resists noise well and provides clear audio for local communications.
T8A05
Which of the following signal types has the narrowest bandwidth?
A. FM voice
B. SSB voice
C. CW ✓
D. Slow-scan TV
Why: CW (Morse code) is simply an on-off carrier and occupies about 150 Hz, far narrower than SSB voice (about 3 kHz), FM voice (10 to 15 kHz) or slow-scan TV.
T8A06
Which sideband is normally used for 10-meter HF, VHF, and UHF single-sideband communications?
A. Upper sideband ✓
B. Lower sideband
C. Suppressed sideband
D. Inverted sideband
Why: By convention, upper sideband (USB) is used on 10 meters and on VHF and UHF SSB. Lower sideband is customary only on the 160, 80 and 40-meter bands.
T8A07
What is one characteristic of single sideband (SSB) compared to FM?
A. SSB signals are easier to tune in correctly
B. SSB signals are less susceptible to interference
C. SSB signals have narrower bandwidth ✓
D. SSB signals are less susceptible to high SWR
Why: An SSB signal is only about 3 kHz wide, compared with 10 to 15 kHz for FM voice. The narrower bandwidth lets more stations fit in a band and concentrates power.
T8A08
What is the approximate bandwidth of a typical single sideband (SSB) voice signal?
A. 1 kHz
B. 3 kHz ✓
C. 6 kHz
D. 15 kHz
Why: SSB carries only one sideband of the voice audio. Voice frequencies used for communications extend to about 3 kHz, so an SSB signal is about 3 kHz wide.
T8A09
What is the approximate bandwidth of an FM voice signal on VHF repeaters?
A. Less than 500 Hz
B. About 150 kHz
C. Between 10 and 15 kHz ✓
D. Between 50 and 125 kHz
Why: A VHF FM repeater voice signal, with about 5 kHz deviation plus audio up to 3 kHz, occupies about 10 to 15 kHz, as Carson's rule shows: 2 x (5 + 3) = 16 kHz.
T8A10
What is the approximate bandwidth of AM fast-scan TV transmissions?
A. More than 10 MHz
B. About 6 MHz ✓
C. About 3 MHz
D. About 1 MHz
Why: Amateur fast-scan TV using AM is similar to analog broadcast TV and requires about 6 MHz of bandwidth. That is why it is used only on 70 centimeters and higher.
T8A11
What is the approximate bandwidth required to transmit a CW signal?
A. 2.4 kHz
B. 150 Hz ✓
C. 1000 Hz
D. 15 kHz
Why: A CW signal needs only about 150 Hz of bandwidth, since it is a carrier switched on and off at speeds of a few words per minute. This makes CW the narrowest common mode.
T8A12
Which of the following is a disadvantage of FM compared with single sideband?
A. Voice quality is poorer
B. Only one signal can be received at a time ✓
C. FM signals are harder to tune
D. FM signals are more susceptible to high SWR
Why: FM receivers exhibit the capture effect: the strongest signal on the channel takes over and weaker ones are suppressed. So only one signal can be heard at a time, unlike SSB where signals overlap.
T8B01
What telemetry information is typically transmitted by satellite beacons?
A. The signal strength of received signals
B. Time of day accurate to plus or minus 1/10 second
C. Health and status of the satellite ✓
D. All these choices are correct
Why: Satellite beacons commonly transmit telemetry about the satellite's health and status, such as battery voltage, temperatures and operating mode. Ground stations use this to monitor the satellite.
T8B02
What is the impact of using excessive effective radiated power on a satellite uplink?
A. Possibility of commanding the satellite to an improper mode
B. Blocking access by other users ✓
C. Overloading the satellite batteries
D. Possibility of rebooting the satellite control computer
Why: Satellite transponders share power among all users. A signal much stronger than necessary takes more than its share, reducing others' signals and potentially blocking their access. Use minimum necessary power.
T8B03
Which of the following are provided by satellite tracking programs?
A. Maps showing the real-time position of the satellite track over Earth
B. The time, azimuth, and elevation of the start, maximum altitude, and end of a pass
C. The apparent frequency of the satellite transmission, including effects of Doppler shift
D. All these choices are correct ✓
Why: Satellite tracking programs show maps of the satellite's real-time position, predict pass times with azimuth and elevation, and calculate Doppler-shifted frequencies. All these choices apply.
T8B04
What mode of transmission is commonly used by amateur radio satellites?
A. SSB
B. FM
C. CW/data
D. All these choices are correct ✓
Why: Amateur satellites use many modes: FM for simple repeater-style satellites, SSB and CW on linear transponders, and various data modes. All these choices are correct.
T8B05
What is a satellite beacon?
A. The primary transmit antenna on the satellite
B. An indicator light that shows where to point your antenna
C. A reflective surface on the satellite
D. A transmission from a satellite that contains status information ✓
Why: A satellite beacon is a transmission from the satellite containing status information, such as telemetry or identification. Hams also use it to locate the satellite's signal and judge uplink levels.
T8B06
Which of the following are inputs to a satellite tracking program?
A. The satellite transmitted power
B. The Keplerian elements ✓
C. The last observed time of zero Doppler shift
D. All these choices are correct
Why: Satellite tracking programs need Keplerian elements, a set of numbers describing a satellite's orbit, to predict where it will be. They are updated regularly and usually downloaded online.
T8B07
What is Doppler shift in reference to satellite communications?
A. A change in the satellite orbit
B. A mode where the satellite receives signals on one band and transmits on another
C. An observed change in signal frequency caused by relative motion between the satellite and Earth station ✓
D. A special digital communications mode for some satellites
Why: Doppler shift is the apparent change in frequency caused by relative motion. As a satellite approaches, its signal frequency appears higher; as it moves away, the frequency appears lower.
T8B08
What does it mean if a satellite is operating in U/V mode?
A. The satellite uplink is in the 15-meter band and the downlink is in the 10-meter band
B. The satellite uplink is in the 70-centimeter band and the downlink is in the 2-meter band ✓
C. The satellite operates using ultraviolet frequencies
D. The satellite frequencies are usually variable
Why: Satellite mode letters name the uplink band first and the downlink second. U/V means a UHF (70-centimeter) uplink and a VHF (2-meter) downlink.
T8B09
What causes spin fading of satellite signals?
A. Circular polarized noise interference radiated from the sun
B. Rotation of the satellite and its antennas ✓
C. Doppler shift of the received signal
D. Interfering signals within the satellite uplink band
Why: As a satellite rotates, its antennas change orientation relative to your station, so the received signal fades in and out at a regular rate. This is spin fading.
T8B10
What does the term LEO mean in reference to communication satellites?
A. Low Energy Orbit, which conserves battery power
B. Low Elevation Orbit, which appears close to the horizon from the earth station
C. Low Equilibrium Orbit, which has a slightly unstable period
D. Low Earth Orbit, which has a period of around 100 minutes ✓
Why: LEO stands for Low Earth Orbit. These satellites orbit a few hundred miles up and circle Earth in roughly 90 to 100 minutes, so passes overhead last only about 10 to 15 minutes.
T8B11
Who is permitted to receive telemetry from an amateur radio satellite?
A. Anyone ✓
B. Only the satellite control operator
C. Only the control operator or a licensed radio amateur who has received the encryption key from the control operator
D. Only a licensed radio amateur who has received the encryption key from AMSAT
Why: Amateur radio transmissions, including satellite telemetry, cannot be encrypted, so anyone may receive and decode it. Telemetry formats are publicly documented.
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?
A. Check your signal strength report in the telemetry data
B. Listen for distortion on your downlink signal
C. Your signal strength on the downlink should be about the same as the beacon ✓
D. Compare your signal to others on the downlink using an internet SDR receiver
Why: On a linear transponder, the beacon provides a reference level. If your downlink signal is about as strong as the beacon, your uplink power is about right; much stronger means you are using too much power.
T8C01
Which of the following methods is used to locate sources of noise interference or jamming?
A. Echolocation
B. Doppler radar
C. Radio direction finding ✓
D. Phase locking
Why: Radio direction finding uses directional antennas and receivers to determine the bearing of a signal from several locations, pinpointing the source of noise, interference or jamming.
T8C02
Which of these items would be useful for a hidden transmitter hunt?
A. Calibrated SWR meter
B. A directional antenna ✓
C. A directional wattmeter
D. All these choices are correct
Why: In a hidden transmitter hunt (fox hunt), a directional antenna such as a small Yagi lets you find the direction of the strongest signal. SWR meters and wattmeters do not help locate signals.
T8C03
What operating activity involves contacting as many stations as possible during a specified period?
A. Simulated emergency exercises
B. Net operations
C. Hidden transmitter hunts
D. Contesting ✓
Why: Contesting is an operating activity where stations try to contact as many other stations as possible during a set period, often exchanging brief information such as location or signal report.
T8C04
Which of the following is good practice when contacting another station in a contest?
A. Signing only the last two letters of your call if there are many other stations calling
B. Contacting the station twice to be sure that you are in his log
C. Sending only the minimum information needed for proper identification and the contest exchange ✓
D. Adding “Please copy” before your exchange
Why: Good contest practice is to send only your full call sign and the required exchange. Partial calls, duplicate contacts and extra words like 'please copy' waste time.
T8C05
What is a grid locator?
A. A letter-number designator assigned to a geographic location ✓
B. A letter-number designator assigned to an azimuth and elevation
C. An instrument for locating faults in power amplifiers
D. An instrument for radio direction finding
Why: A grid locator, part of the Maidenhead system, is a letter-number code such as FN31 identifying a geographic area on Earth. VHF contesters and many awards use grid squares.
T8C06
How is over the air access to Internet Radio Linking Project (IRLP) nodes accomplished?
A. By obtaining a password that is sent via voice to the node
B. By using Dual-Tone Multi-Frequency (DTMF) signals ✓
C. By entering the proper internet password
D. By using Continuous Tone-Coded Squelch System (CTCSS) tone codes
Why: IRLP nodes are accessed over the air by sending DTMF (touch-tone) codes from your radio to connect to or disconnect from other nodes. CTCSS only opens squelch.
T8C07
What is Voice Over Internet Protocol (VoIP)?
A. A set of rules specifying how to identify your station when linked over the internet to another station
B. A technique employed to “spot” DX stations via the internet
C. A technique for measuring the modulation quality of a transmitter using remote sites monitored via the internet
D. A method of delivering voice communications over the internet using digital techniques ✓
Why: Voice over Internet Protocol (VoIP) is a method of delivering voice communications over the internet by converting voice into digital data packets. EchoLink and IRLP use VoIP.
T8C08
What is the Internet Radio Linking Project (IRLP)?
A. A technique to connect amateur radio systems, such as repeaters, via the internet ✓
B. A system for providing access to websites via amateur radio
C. A system for informing amateurs in real time of the frequency of active DX stations
D. A technique for measuring signal strength of an amateur transmitter via the internet
Why: The Internet Radio Linking Project (IRLP) connects amateur radio systems such as repeaters through the internet using VoIP, allowing stations to talk through repeaters worldwide.
T8C09
Which of the following protocols enables an amateur station to transmit through a repeater without using a radio to initiate the transmission?
A. IRLP
B. D-STAR
C. DMR
D. EchoLink ✓
Why: EchoLink lets a licensed amateur connect from a computer or smartphone over the internet to an EchoLink-enabled repeater or link and transmit without using a radio.
T8C10
What is required before using the EchoLink system?
A. Complete the required EchoLink training
B. Purchase a license to use the EchoLink software
C. Register your call sign and provide proof of license ✓
D. At least a General Class license
Why: EchoLink requires you to register your call sign and provide proof of license so only licensed amateurs can transmit. The software is free, and Technicians may use it.
T8C11
What is an amateur radio station that connects other amateur stations to the internet?
A. A gateway ✓
B. A repeater
C. A digipeater
D. A beacon
Why: A gateway is an amateur station that connects other amateur stations to the internet, such as an EchoLink or APRS internet gateway. A repeater or digipeater only retransmits radio signals.
T8D01
Which of the following is a digital communications mode?
A. Packet radio
B. IEEE 802.11
C. FT8
D. All these choices are correct ✓
Why: Packet radio, IEEE 802.11 (Wi-Fi-based amateur networks), and FT8 are all digital communications modes, sending information as digital data. All choices are correct.
T8D02
What is FT8?
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
Why: FT8 is a digital mode designed to decode signals with a very low signal-to-noise ratio, often below the noise you can hear. It uses 15-second timed transmission cycles and is popular for weak-signal contacts.
T8D03
What kind of data can be transmitted by APRS?
A. GPS position data
B. Text messages
C. Weather data
D. All these choices are correct ✓
Why: APRS (Automatic Packet Reporting System) can carry GPS position reports, short text messages, and weather station data, all shown on maps. So all these choices are correct.
T8D04
What is meant by the term "NTSC?"
A. A digital transmission standard for encrypting data
B. A special mode for satellite uplink
C. An analog fast-scan color TV signal ✓
D. A frame compression scheme for TV signals
Why: NTSC is the analog fast-scan color TV standard formerly used for US broadcast television. Amateurs use it for analog TV transmission on 70 centimeters and above.
T8D05
Which of the following is an application of APRS?
A. Providing real-time tactical digital communications in conjunction with a map showing the locations of stations ✓
B. Automatically showing 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
Why: APRS provides real-time tactical digital communications, with positions of stations shown on a map. It is useful for public service events and emergencies.
T8D06
What does the abbreviation "PSK" mean?
A. Pulse Shift Keying
B. Phase Shift Keying ✓
C. Packet Sampled Keying
D. Power Sampled Keying
Why: PSK stands for Phase Shift Keying, a digital mode where data is sent by shifting the phase of the signal. PSK31 is a popular narrow keyboard-to-keyboard mode.
T8D07
Which of the following describes DMR?
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
Why: DMR (Digital Mobile Radio) uses time-division multiplexing, giving two time slots on one 12.5 kHz channel. So one repeater can carry two separate digital voice conversations at once.
T8D08
Which of the following is included in packet radio transmissions?
A. A checksum 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 ✓
Why: Packet radio transmissions include a header with the destination call sign, a checksum to detect errors, and automatic repeat request (ARQ) to resend data received with errors. All these choices apply.
T8D09
What is CW?
A. A type of electromagnetic propagation
B. A digital mode used primarily on 2-meter FM
C. Error correction for digital transmission using code words
D. Another name for a Morse code transmission ✓
Why: CW, short for continuous wave, is the amateur term for transmitting Morse code by switching a carrier on and off. It is the oldest and narrowest amateur mode.
T8D10
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 ✓
Why: The WSJT-X software suite includes modes for Earth-Moon-Earth (moonbounce), weak-signal propagation beacons (WSPR) and meteor scatter, among others. All these choices apply.
T8D11
What is the role of ARQ in a transmission system?
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
Why: ARQ (Automatic Repeat reQuest) is an error correction method where the receiving station checks incoming data and asks the sender to retransmit any block that contains errors.
T8D12
Which of the following best describes an amateur radio mesh network?
A. An amateur-radio data network using commercial Wi-Fi equipment with modified firmware ✓
B. A wide-bandwidth digital voice mode employing DMR protocols
C. An amateur-radio satellite communications network using modified commercial satellite TV hardware
D. An internet linking protocol allowing communication through repeaters around the world
Why: An amateur radio mesh network is a high-speed data network built using commercial Wi-Fi equipment with modified firmware so it can operate under amateur rules on shared amateur frequencies.