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Question #561Radio Theory and Communication Principles

Which term describes the ability of a receiver to discriminate between multiple signals?

  1. Tuning rate
  2. Sensitivity
  3. Selectivity ✓ Correct answer
  4. Noise floor

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Question #562Radio Theory and Communication Principles

Where is an RF pre-amplifier installed?

  1. between the antenna and receiver ✓ Correct answer
  2. At the output of the transmitters power amplifier
  3. Between a transmitter and antenna tuner
  4. At the receiver's audio output

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Question #563Radio Theory and Communication Principles

Why is UHF signals often more effective from inside buildings than VHF signals?

  1. VHF signals lose power faster over distance
  2. the shorter wavelength allows them to more easily penetrate the structure of buildings ✓ Correct answer
  3. This is incorrect; VHF works better than UHF inside buildings
  4. UHF antennas are more efficient than VHF antennas

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Question #564Antennas and Radio Wave Propagation

Which part of the atmosphere enables the propagation of radio signals around the world?

  1. The stratosphere
  2. The troposphere
  3. The ionosphere ✓ Correct answer
  4. The mesosphere

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Question #565Antennas and Radio Wave Propagation

What causes “tropospheric ducting"?

  1. Discharges of lightning during electrical storms
  2. Sunspots and solar flares
  3. Updrafts from hurricanes and tornadoes
  4. Temperature inversions in the atmosphere ✓ Correct answer

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Question #566Radio Theory and Communication Principles

What are the two components of a radio wave?

  1. AC and DC
  2. Voltage and current
  3. Electric and magnetic fields ✓ Correct answer
  4. Ionizing and non-ionizing radiation

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Question #567Radio Theory and Communication Principles

What is the function of a mixer in a super-heterodyne receiver?

  1. To reject signals outside of the desired passband
  2. To combine signals from several stations together
  3. To shift the incoming signal with an intermediate frequency ✓ Correct answer
  4. To connect the receiver with an auxiliary device

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Question #568Basic Electricity and Electronics

Which of the following circuits combines a speech signal and an RF carrier?

  1. Beat frequency Oscillator
  2. Discriminator
  3. Modulator ✓ Correct answer
  4. Noise blanker

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Question #569Antennas and Radio Wave Propagation

What is meant by the gain of an antenna?

  1. The additional power that is added to the transmitter power
  2. The additional power that is lost in the antenna when transmitting on a higher frequency
  3. the increase in signal strength when compared to a reference antenna ✓ Correct answer
  4. The increase in impedance on receive or transmit compared to a reference antenna

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Question #570Basic Electricity and Electronics

A Diode can be used as

  1. Rectifier ✓ Correct answer
  2. Amplifier
  3. Oscillator
  4. All the above

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Question #571Radio Theory and Communication Principles

An Oscillator is based on

  1. Positive feedback ✓ Correct answer
  2. Negative feedback
  3. No feedback
  4. both a & b

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Question #572Antennas and Radio Wave Propagation

Which of the following instruments can be used to determine if an antenna is resonant at the designed frequency?

  1. A multimeter
  2. Antenna analyzer ✓ Correct answer
  3. A “Q” meter
  4. A frequency counter

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Question #573Radio Theory and Communication Principles

What does the term “RIT" mean?

  1. Receiver Input Tone
  2. Receiver Incremental Tuning ✓ Correct answer
  3. Rectifier Inverter Test
  4. Remote input Transmitter

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Question #574Radio Theory and Communication Principles

A common use for a permanent magnet is

  1. A computer speaker ✓ Correct answer
  2. An optical mouse
  3. A keyboard
  4. A magnetic loop antenna

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Question #575Basic Electricity and Electronics

In a p-type semiconductor, the current carriers are

  1. photons
  2. electrons
  3. positive ions
  4. holes ✓ Correct answer
Explanation: In a p-type semiconductor the majority carriers are holes.

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Question #576Basic Electricity and Electronics

A simple transmitter requires a 50 ohm dummy load. You can fabricate this from

  1. four 300 ohm resistors in parallel
  2. five 300 ohm resistors in parallel
  3. six 300 ohm resistors in parallel ✓ Correct answer
  4. seven 300 ohm resistors in parallel

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Question #577Basic Electricity and Electronics

A component is identified as a capacitor if its value is measured in

  1. Microvolts
  2. Milli henrys
  3. Megohms
  4. Micro farads ✓ Correct answer
Explanation: Capacitance is measured in farads (or microfarads). Millihenrys measure inductance.

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Question #578Radio Theory and Communication Principles

A "linear amplifier" is

  1. an amplifier to remove distortion in signals from the transceiver
  2. an optional amplifier to be switched in when higher power is required ✓ Correct answer
  3. an amplifier with all components arranged in-line
  4. a push-pull amplifier to cancel second harmonic distortion

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Question #579Antennas and Radio Wave Propagation

A dummy antenna

  1. attenuates a signal generator to a desirable level
  2. provides more selectivity when a transmitter is being tuned
  3. matches an AF generator to the receiver
  4. duplicates the characteristics of an antenna without radiating signals ✓ Correct answer

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Question #580Radio Theory and Communication Principles

Of two receivers, the one capable of receiving the weakest signal will have:

  1. an RF gain control
  2. the least internally-generated noise ✓ Correct answer
  3. the loudest audio output
  4. the greatest tuning range
Explanation: The receiver that can copy the weakest signals has the least internally generated noise (better noise figure).

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