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US_TECH_2022_2026

Technician 2022-2026 - Signals, emissions, and modulation

Signals, emissions, and modulation groups the T8 section questions for focused review and easier weak-point tracking.

48
Questions
9
Sibling Topics
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Pool
Technician 2022-2026
Questions
48
Topic
Signals, emissions, and modulation
Region
US
Read the condition in the stem before comparing key terms in the options.
Study rules, calculations, and equipment questions as separate patterns.
After this topic, return to the full pool for mixed practice.

Topic Study Guide

This topic covers the fundamentals of radio signals, modulation types, satellite communications, and digital modes. You will learn to identify bandwidth requirements for different modes and understand how internet-linked radio systems operate.

High-Yield Checks

  • Bandwidths: CW is the narrowest (~150 Hz), SSB is ~2.4 kHz, and FM voice is 10-15 kHz.
  • Satellite terms: Doppler shift (frequency change), spin fading (rotation), telemetry (health/status), and beacons. Anyone can receive telemetry.
  • Digital & Internet modes: EchoLink allows PC/phone access without a radio. Gateways connect RF to the internet. DMR uses "talkgroups" to share channels.
  • Modulation basics: SSB is a form of AM used for weak-signal/long-distance VHF/UHF. PSK stands for Phase Shift Keying.

Trap Patterns

  • Confusing Doppler shift (frequency change due to motion) with spin fading (signal fading due to antenna rotation).
  • Assuming you need a special license or code to receive satellite telemetry (Fact: Anyone can receive it).
  • Mistaking NTSC for a modern digital mode instead of an analog fast-scan color TV signal.
  • Selecting "FM" for long-distance weak-signal VHF/UHF contacts instead of "SSB".

Review Steps

  • Memorize the bandwidth numbers for CW, SSB, and FM voice in order from narrowest to widest.
  • Group satellite vocabulary (Doppler, telemetry, beacon, spin fading) and define each in one short sentence.
  • Differentiate internet-linked systems: know the specific roles of EchoLink, VoIP, and Gateways.
  • Review acronyms like PSK, NTSC, and DMR talkgroups to ensure you know what the letters stand for and their primary function.

Quick Checks

  • What is the approximate bandwidth of a CW signal versus an FM voice signal?
  • Which mode is best for long-distance weak-signal contacts on VHF/UHF?
  • What causes spin fading in satellite communications?
  • What is the function of a gateway in amateur radio?

Questions in This Topic

Choose Practice Mode
T8A01Which of the following is a form of amplitude modulation?T8A02What type of modulation is commonly used for VHF packet radio transmissions?T8A03Which type of voice mode is often used for long-distance (weak signal) contacts on the VHF and UHF bands?T8A04Which type of modulation is commonly used for VHF and UHF voice repeaters?T8A05Which of the following types of signal has the narrowest bandwidth?T8A06Which sideband is normally used for 10 meter HF, VHF, and UHF single-sideband communications?T8A07What is a characteristic of single sideband (SSB) compared to FM?T8A08What is the approximate bandwidth of a typical single sideband (SSB) voice signal?T8A09What is the approximate bandwidth of a VHF repeater FM voice signal?T8A10What is the approximate bandwidth of AM fast-scan TV transmissions?T8A11What is the approximate bandwidth required to transmit a CW signal?T8A12Which of the following is a disadvantage of FM compared with single sideband?T8B01What telemetry information is typically transmitted by satellite beacons?T8B02What is the impact of using excessive effective radiated power on a satellite uplink?T8B03Which of the following are provided by satellite tracking programs?T8B04What mode of transmission is commonly used by amateur radio satellites?T8B05What is a satellite beacon?T8B06Which of the following are inputs to a satellite tracking program?T8B07What is Doppler shift in reference to satellite communications?T8B08What is meant by the statement that a satellite is operating in U/V mode?T8B09What causes spin fading of satellite signals?T8B10What is a LEO satellite?T8B11Who may receive telemetry from a space station?T8B12Which of the following is a way to determine whether your satellite uplink power is neither too low nor too high?T8C01Which of the following methods is used to locate sources of noise interference or jamming?T8C02Which of these items would be useful for a hidden transmitter hunt?T8C03What operating activity involves contacting as many stations as possible during a specified period?T8C04Which of the following is good procedure when contacting another station in a contest?T8C05What is a grid locator?T8C06How is over the air access to IRLP nodes accomplished?T8C07What is Voice Over Internet Protocol (VoIP)?T8C08What is the Internet Radio Linking Project (IRLP)?T8C09Which of the following protocols enables an amateur station to transmit through a repeater without using a radio to initiate the transmission?T8C10What is required before using the EchoLink system?T8C11What is an amateur radio station that connects other amateur stations to the internet?T8D01Which of the following is a digital communications mode?T8D02What is a “talkgroup” on a DMR repeater?T8D03What kind of data can be transmitted by APRS?T8D04What type of transmission is indicated by the term "NTSC?"T8D05Which of the following is an application of APRS?T8D06What does the abbreviation "PSK" mean?T8D07Which of the following describes DMR?T8D08Which of the following is included in packet radio transmissions?T8D09What is CW?T8D10Which of the following operating activities is supported by digital mode software in the WSJT-X software suite?T8D11What is an ARQ transmission system?T8D12Which of the following best describes an amateur radio mesh network?T8D13What is FT8?

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