Comm Stuff Volume 2 UREs
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- 1.Which US government agency divides the radio frequency spectrum into different bands?
- A.
Federal Aviation Agency.
- B.
American National Standard Institute.
- C.
Federal Communications Commission (FCC).
- D.
Institute of Electrical & Electronics Engineers, Inc.
- 2.High-frequency (HF) transmissions are normally conducted in which two operating modes?
- A.
Frequency modulation (FM) and independent sidebands (ISB).
- B.
Continuous wave (CW) and amplitude modulation (AM).
- C.
Single side band (SSB) and FM.
- D.
SSB and ISB.
- 3.Which frequency band is most susceptible to jamming?
- A.
Low frequency (LF).
- B.
Medium frequency (MF).
- C.
High frequency (HF).
- D.
Very high frequency (VHF).
- 4.The ability of a receiver to reproduce the signal of a very weak station is characteristic of a receiver’s
- A.
Fidelity.
- B.
Capacity.
- C.
Sensitivity.
- D.
Selectivity.
- 5.A combination transmitter and receiver, built as a single unit and shares common tuned circuits, is called a
- A.
Transmitter.
- B.
Transceiver.
- C.
Receiver.
- D.
Coupler.
- 6.Conductor material resistance in a transmission line leads to this type of loss.
- A.
Copper.
- B.
Radiation.
- C.
Inductive.
- D.
Skin-effect.
- 7.The amount of skin-effect loss is directly proportional to the
- A.
Line length.
- B.
Frequency.
- C.
Voltage level.
- D.
Resistive loss.
- 8.Leakage loss in a transmission line is minimized by using a
- A.
Thinner conductor.
- B.
Thicker conductor.
- C.
Very low-resistance dielectric.
- D.
Very high-resistance dielectric.
- 9.A transmission line that consists of a center conductor, placed inside a rigid metal tube that functions as the outer shield, is called
- A.
Flexible coaxial cable.
- B.
Rigid coaxial cable.
- C.
Waveguide.
- D.
Twin lead.
- 10.A waveguide is a type of transmission line that you would use
- A.
When the frequencies are so high that their wavelength is miniscule.
- B.
To transmit on frequencies too low for ground propagation.
- C.
For high power at frequencies up to 30 megahertz (MHz) primarily.
- D.
To receive television frequencies over the air.
- 11.All statements concerning waveguides are true except
- A.
Their outer surface will arc from being very slightly damaged.
- B.
Their conductive material construction is easily dented.
- C.
Their effectiveness is hindered by moisture.
- D.
They can be destroyed by corrosion.
- 12.Which two transmission line properties determine its characteristic impedance (ZO)?
- A.
Inductance and resistance.
- B.
Inductance and capacitance.
- C.
Resistance and capacitance.
- D.
Length and type of shielding.
- 13.This is the correct statement concerning a wavelength.
- A.
Wavelength is inversely related to frequency.
- B.
Wavelength is directly related to frequency.
- C.
Wavelength is determined by the line length.
- D.
Wavelength is expressed in lambdas (λ).
- 14.Determine the wavelength of a 250 megahertz (MHz) signal.
- A.
12.0 meters.
- B.
3.0 meters.
- C.
1.5 meters.
- D.
1.2 meters.
- 15.A nonresonant transmission line is one with
- A.
Reflected waves.
- B.
No reflected waves.
- C.
Maximum voltage across its open termination.
- D.
Maximum voltage across its shorted termination.
- 16.When discussing resonant and nonresonant transmission lines,
- A.
Resonant lines are often referred to as flat lines.
- B.
Maximum power transfer results from a resonant line.
- C.
Maximum power transfer results from a nonresonant line.
- D.
Significant loss and damage to equipment results from using a nonresonant line.
- 17.This will likely result if a transmission line is terminated in an open.
- A.
Signal loss would be negligible.
- B.
Signal loss would be significant.
- C.
Current would be maximum at the termination.
- D.
Voltage would be minimum at the termination.
- 18.Direct waves are radio waves that travel
- A.
Long distances with few interruptions.
- B.
From point to point along the Earth’s surface.
- C.
No more than 20 miles to the receive antenna.
- D.
Through the air in a straight line from transmitter to receiver.
- 19.Radio waves that travel near the Earth’s surface are called
- A.
Earth waves.
- B.
Global waves.
- C.
Ground waves.
- D.
Terrestrial waves.
- 20.The Earth’s conductivity is determined by the type of
- A.
Atmospheric conditions at the time of transmission.
- B.
Air and moisture content in the propagation path.
- C.
Soil and water in the propagation path.
- D.
Soil and air in the propagation path.
- 21.This term is used to describe radio waves that bend as they travel from one medium to another that has different density.
- A.
Diffusion.
- B.
Diffraction.
- C.
Refraction.
- D.
Reflection.
- 22.The refractive index of air depends on moisture,
- A.
Atmospheric pressure, and temperature.
- B.
Atmospheric pressure, and frequency.
- C.
Receive signal level, and temperature.
- D.
Receive signal level, and frequency.
- 23.When comparing the radio and optical horizons, which one is farther away and by what percentage?
- A.
Optical; 15.
- B.
Radio; 15.
- C.
Optical; 33.
- D.
Radio; 33.
- 24.Which process permits communication in shadow regions behind obstacles?
- A.
Reflection.
- B.
Scattering.
- C.
Refraction.
- D.
Diffraction.
- 25.Which frequency range will show little effect from precipitation?
- A.
High frequency (HF).
- B.
Ultra-high frequency (UHF).
- C.
Super-high frequency (SHF).
- D.
Extremely-high frequency (EHF).
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