CDC 3D153 v2 URE Flashcards
Equipment used for generating, amplifying, and transmitting RF carrier is collectively calleda. a receiver.b. an antenna.c. a transmitter.d. a transmission line.
c. a transmitter.
What basic receiver function involves having the transmitted electromagnetic wave pass through the receive antenna in such a manner as to induce a voltage in the antenna?a. Reproduction.b. Reception.c. Detection.d. Selection.
b. Reception.
The ability to reproduce the input signal accurately is the characteristics of the receiver’sa. fidelity.b. capacity.c. sensitivity.d. selectivity.
a. fidelity.
A combination of a transmitter and receiver that is built as a single unit and sharing common tuned circuits is called aa. transmitter.b. transceiver.c. receiver.d. coupler.
b. transceiver.
Which of the following cannot be performed by the transceiver’s computerized components and micro-circuitry?a. specific equipment faults.b. internal equipment tests.c. internal calibrations.d. repair itself.
d. repair itself.
A transmission line that consists of a center conductor placed inside a metal tube functioning as the outer tube is called aa. flexible coaxial cable.b. rigid coaxial cable.c. waveguide.d. twin lead.
b. rigid coaxial cable.
Which selection best describes the term “cutoff frequency” when discussing transmission line properties?XL = X_L XC= X_Ca. The frequency where XL becomes so low that the signal is shunted.b. The frequency where XC causes the signal to be shunted.c. The lowest frequency that the line can pass successfully.d. The frequency at which standing waves are maximum.
b. The frequency where XC causes the signal to be shunted..
Using figure 1–10, determine the wavelength if the frequency is changed from 150 MHz to 250 MHz.a. 12.0 meters.b. 3.0 meters.c. 1.5 meters.d. 1.2 meters.
d. 1.2 meters.
Using figure 1–10, determine the electrical length if the frequency is changed from 150 MHz to 250 MHz.a. 8.33 meters.b. 8.33 wavelengths.c. 83.3 meters.d. 83.3 wavelengths.
b. 8.33 wavelengths.
A nonresonant transmission line is a linea. having reflected waves.b. having no reflected waves.c. with maximum voltage across its open termination.d. with maximum voltage across its shorted termination.
b. having no reflected waves.
If a transmission line is terminated in a short,a. current is at maximum and voltage at minimum at the termination.b. current is at minimum and voltage at maximum at the termination.c. there would be a nominal amount of signal gain.d. the line would be nonresonant.
a. current is at maximum and voltage at minimum at the termination.
In a basic communication system, what converts radio frequency (RF) energy’s current oscillation into electric and magnetic fields of force?a. Antenna.b. Coupler.c. Transmitter.d. Transmission lines.
a. Antenna.
The concept that alternating current (AC) changes in magnitude and reverses its direction during each cycle isa. an unproven hypothesis.b. the definition of propagation.c. what makes radio transmission possible.d. what led to the discovery of direct current.
c. what makes radio transmission possible.
If the electric field component travels in a plane perpendicular to the Earth’s surface, the radio wave isa. magnetically polarized.b. horizontally polarized.c. circularly polarized.d. vertically polarized.
d. vertically polarized.
What types of polarization do satellite terminals transmit and receive?a. Transmit horizontal and receive vertical polarizations.b. Transmit vertical and receive horizontal polarizations.c. Transmit right hand and receive left hand circular polarizations.d. Transmit left hand and receive right hand circular polarizations.
c. Transmit right hand and receive left hand circular polarizations.
What measurement is used to determine whether an antenna is resonant at a particular frequency?a. Distortion.b. Standing wave ratio.c. Signal-to-noise ratio.d. Percent of modulation.
b. Standing wave ratio.
The ability of an antenna to both receive and transmit equally well is known as theantenna’sa. bandwidth.b. resonance.c. reciprocity.d. effectiveness.
c. reciprocity.
The standard used to measure the radiating effectiveness (gain) of an antenna system is thea. Marconi antenna.b. isotropic antenna.c. Hertz antenna.d. whip antenna.
b. isotropic antenna.
What does the effectiveness of an entire transmitting and receiving system depend largely upon?a. Impedance matching.b. Antenna distance.c. Antenna properties.d. Line characteristics.
a. Impedance matching.
Which antenna radiates radio energy in a circular pattern?a. Omnidirectional.b. Unidirectional.c. Bidirectional.d. Directional.
a. Omnidirectional.
Which antenna type is usually used on long-range, point-to-point circuits where the concentrated radio energy is needed for circuitry reliability?a. Omnidirectional.b. Unidirectional.c. Bidirectional.d. Circular.
b. Unidirectional.
Ungrounded lengths of wire specifically designed to be either a half-wavelength or more than full wavelength long is called aa. reflector.b. Hertz antenna.c. Marconi antenna.d. vertical monopole.
b. Hertz antenna.
A long-wire’s takeoff angle depends on the antenna’sa. length.b. directivity.c. front-to-back ratio.d. standing wave ratio.
a. length.
All antennas used in satellite communications are designed to bea. circular directional.b. omnidirectional.c. bidirectional.d. directional.
d. directional.
A common satellite antenna is thea. whip.b. discone.c. parabolic.d. long-wire.
c. parabolic.
A helical antenna radiates a signal with what type of polarization?a. Horizontal.b. Vertical.c. Circular.d. Linear.
c. Circular.
Aircraft antennas are houseda. inside nonconductive radomes mounted outside or flush with the fuselage.b. inside conductive radomes mounted outside or flush with the fuselage.c. outside nonconductive radomes mounted outside the fuselage.d. inside conductive radomes mounted flush with the fuselage.
a. inside nonconductive radomes mounted outside or flush with the fuselage.
In airborne antenna applications for frequencies in the upper portion of the HF band, what vertical angles are used for multi-hop, long distance transmission?a. 90 and 180 degrees.b. 60 and 90 degrees.c. 30 and 60 degrees.d. 5 and 30 degrees.
d. 5 and 30 degrees.
What determines an antenna’s location and orientation on the aircraft?a. Antennas always require a 360° radiating pattern.b. The type of aircraft propulsion and power system.c. Antennas are always mounted on top of the fuselage.d. Optimizing the antenna’s radiating pattern for its application.
d. Optimizing the antenna’s radiating pattern for its application.
Which type of airborne antenna can be designed into any part of an aerospace vehicle’s surface, so that it does not upset its aerodynamic properties?a. Fixed blade.b. Conformal.c. Probe tip.d. Whip.
b. Conformal.
In selecting an antenna for a circuit, what is the first thing to look at?a. Type of propagation.b. Selecting the antenna.c. Determine the distance.d. Finding the operating frequency.
a. Type of propagation.
Which object has the greatest effect on an antenna?a. Sun.b. Earth.c. Operator.d. Ionosphere.
b. Earth.
Where is the most challenging location for a radio frequency (RF) transmission systems technician to establish and operate a radio station from?a. Amazon jungle.b. North Pole.c. Sahara desert.d. Sierra Nevada mountains.
a. Amazon jungle.
With a mountain between you and the distant end, which antenna is more effective?a. Whip.b. Dipole.c. Discone.d. Near-vertical incidence skywave.
d. Near-vertical incidence skywave.
Direct waves are radio waves that travela. long distances with few interruptions.b. from point to point along the earth’s surface.c. through the air in a straight line.d. no more than 20 miles to the receive antenna.
c. through the air in a straight line.
Radio waves that travel near the earth’s surface are calleda. earth waves.b. global waves.c. ground waves.d. terrestrial waves.
c. ground waves.
Sky wave transmission is used for which type of communications?a. Long distance.b. Subterrestrial.c. Atmospheric.d. Line of sight.
a. Long distance.
The path that undergoes a 180° phase shift is aa. ground-reflected path.b. surface path.c. direct path.d. sky path.
a. ground-reflected path.
Which gives sky wave propagation its ability to communicate beyond the optical line-of-sight (LOS)?a. Refraction.b. Reflection.c. Earth’s conductivity.d. Atmospheric charge.
a. Refraction.
Frequencies higher than the critical frequency area. returned to earth.b. passed into space.c. the most desirable.d. refracted by the F2 layer.
b. passed into space.