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US_TECH_2026_2030

Technician 2026-2030 - Signals, emissions, and modulation

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

47
Questions
9
Sibling Topics
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Pool
Technician 2026-2030
Questions
47
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 common modulation methods (AM, FM, SSB, CW), bandwidth requirements, satellite communication basics, and digital modes (FT8, EchoLink, Packet radio) used in amateur radio.

High-Yield Checks

  • Bandwidth comparisons: CW is the narrowest (~150 Hz), SSB is narrower than FM, and VHF FM voice is typically 10-15 kHz.
  • Satellite basics: Beacons transmit health status, Doppler shift is caused by relative motion, and anyone can receive telemetry.
  • Digital & Internet modes: FT8 is for low signal-to-noise environments, EchoLink allows transmitting without a radio, and Gateways connect stations to the internet.
  • SSB characteristics: It is a form of Amplitude Modulation (AM) and is preferred for weak-signal, long-distance VHF/UHF contacts.

Trap Patterns

  • Mistaking Single Sideband (SSB) for a completely independent modulation type; it is actually a bandwidth-efficient form of AM.
  • Assuming receiving amateur satellite telemetry requires a license or encryption key; it is legally open to anyone.
  • Confusing IRLP and EchoLink. Remember that EchoLink can be initiated entirely via computer or phone without an RF radio.
  • Mistaking NTSC for a modern digital TV standard; it is actually a traditional analog fast-scan color TV signal.

Review Steps

  • Prioritize memorizing bandwidth values: CW (150 Hz) < SSB < FM (10-15 kHz).
  • Group satellite terms together for memorization, including Beacon, Doppler shift, and Spin fading.
  • Differentiate network and digital acronyms, such as PSK (Phase Shift Keying), FT8 (weak signal digital mode), and VoIP (Voice over IP).

Quick Checks

  • Which mode has the narrowest bandwidth, and what is its approximate value?
  • What causes spin fading in satellite signals?
  • What is the primary purpose of a satellite beacon?
  • Which protocol allows transmission through a repeater without using a 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 signal types has the narrowest bandwidth?T8A06Which sideband is normally used for 10-meter HF, VHF, and UHF single-sideband communications?T8A07What is one 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 an FM voice signal on VHF repeaters?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 does it mean if a satellite is operating in U/V mode?T8B09What causes spin fading of satellite signals?T8B10What does the term LEO mean in reference to communication satellites?T8B11Who is permitted to receive telemetry from an amateur radio satellite?T8B12Which 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?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 practice when contacting another station in a contest?T8C05What is a grid locator?T8C06How is over the air access to Internet Radio Linking Project (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 FT8?T8D03What kind of data can be transmitted by APRS?T8D04What is meant 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 the role of ARQ in a transmission system?T8D12Which of the following best describes an amateur radio mesh network?

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