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194 matching questions

Question #583Radio Theory and Communication Principles

Morse code is usually transmitted by radio as

  1. an interrupted carrier ✓ Correct answer
  2. a voice modulated carrier
  3. a continuous carrier
  4. a series of clicks

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Question #586Radio Theory and Communication Principles

All communications frequencies throughout the spectrum are affected in varying degrees by the

  1. atmospheric conditions
  2. ionosphere
  3. aurora Borealis
  4. sun ✓ Correct answer

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Question #657Radio Theory and Communication Principles

Modulation is the process of

  1. Superimposing information on a carrier wave ✓ Correct answer
  2. Removing noise from a signal
  3. Amplifying DC
  4. Generating pure DC
Explanation: Modulation puts information onto a radio-frequency carrier.

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Question #658Radio Theory and Communication Principles

Demodulation is the process of

  1. Recovering information from a modulated carrier ✓ Correct answer
  2. Generating a carrier
  3. Increasing SWR
  4. Filtering DC only
Explanation: Demodulation (detection) recovers the original information.

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Question #659Radio Theory and Communication Principles

AM stands for

  1. Amplitude Modulation ✓ Correct answer
  2. Angle Modulation
  3. Audio Mixing
  4. Automatic Matching
Explanation: AM means Amplitude Modulation.

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Question #660Radio Theory and Communication Principles

FM stands for

  1. Frequency Modulation ✓ Correct answer
  2. Force Modulation
  3. Full Modulation
  4. Field Matching
Explanation: FM means Frequency Modulation.

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Question #661Radio Theory and Communication Principles

SSB stands for

  1. Single Sideband ✓ Correct answer
  2. Double Sideband
  3. Suppressed Sideband only
  4. Simple Sideband
Explanation: SSB means Single Sideband.

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Question #662Radio Theory and Communication Principles

The intermediate frequency (IF) in many AM broadcast receivers is

  1. 455 kHz ✓ Correct answer
  2. 10.7 MHz
  3. 1 MHz
  4. 455 MHz
Explanation: A common AM broadcast IF is 455 kHz.

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Question #663Radio Theory and Communication Principles

A common IF used in FM broadcast receivers is

  1. 10.7 MHz ✓ Correct answer
  2. 455 kHz
  3. 1 MHz
  4. 455 MHz
Explanation: A common FM broadcast IF is 10.7 MHz.

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Question #664Radio Theory and Communication Principles

SWR stands for

  1. Standing Wave Ratio ✓ Correct answer
  2. Signal Wave Ratio
  3. Simple Wave Reading
  4. Series Wave Resistance
Explanation: SWR is Standing Wave Ratio.

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Question #665Radio Theory and Communication Principles

An SWR of 1:1 indicates

  1. Perfect match ✓ Correct answer
  2. Severe mismatch
  3. Open circuit only
  4. Short circuit only
Explanation: 1:1 SWR means the load matches the line impedance.

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Question #666Radio Theory and Communication Principles

A dummy load is used to

  1. Test a transmitter without radiating ✓ Correct answer
  2. Increase antenna gain
  3. Receive weak signals
  4. Measure frequency only
Explanation: A dummy load absorbs RF power for testing without radiation.

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Question #672Radio Theory and Communication Principles

CW in amateur radio usually means

  1. Continuous Wave (Morse) ✓ Correct answer
  2. Carrier Width
  3. Coded Width
  4. Circuit Watt
Explanation: CW commonly refers to Morse code / continuous-wave telegraphy.

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Question #673Radio Theory and Communication Principles

The bandwidth of an SSB voice signal is typically about

  1. 2.4 to 3 kHz ✓ Correct answer
  2. 15 kHz
  3. 150 kHz
  4. 1 Hz
Explanation: SSB voice channels are typically a few kilohertz wide.

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