Flashcards in CDC 3D153 v2 URE Deck (100):
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.
The ability to reproduce the input signal accurately is the characteristics of the receiver’sa. fidelity.b. capacity.c. sensitivity.d. selectivity.
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.
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.
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.
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.
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.
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.
All antennas used in satellite communications are designed to bea. circular directional.b. omnidirectional.c. bidirectional.d. directional.
A common satellite antenna is thea. whip.b. discone.c. parabolic.d. long-wire.
A helical antenna radiates a signal with what type of polarization?a. Horizontal.b. Vertical.c. Circular.d. Linear.
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.
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.
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.
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.
In high frequency (HF) communications, the lowest frequency that arrives at the distant receiver on 90 percent of the undisturbed days of the month is called thea. maximum usable frequency ( MUF).b. lowest usable frequency (LUF).c. operating frequency.d. critical frequency.
b. lowest usable frequency (LUF).
The abbreviation FOT is derived from the terma. outbound traffic frequency.b. optimum tropospheric frequency.c. frequency of optimum transmission.d. frequency of outbound transmission.
c. frequency of optimum transmission.
Magneton splitting creates two waves calleda. direct and indirect.b. ordinary and abnormal.c. in-phase and out-of-phase.d. ordinary and extraordinary.
d. ordinary and extraordinary.
What occurs when a transmitted signal travels over two or more separate paths during transmission?a. Skip effects.b. Modulation.c. Multipathing.d. Magneton splitting.
What is the recombination process dependent upon?a. Season.b. Time of day.c. Regular variation.d. Irregular variations.
b. Time of day.
Which layer of the ionosphere is most important to high frequency (HF) communications?a. D.b. E.c. F.d. Topside.
During what season do we have the wider range of critical frequencies and less absorption of all frequencies?a. Fall.b. Winter.c. Spring.d. Summer.
Sunspots are disturbancesa. in the sun’s atmosphere.b. on the sun’s surface.c. in the ionosphere.d. beneath the sun’s surface.
b. on the sun’s surface.
For communications purposes, the usable frequency spectrum ranges froma. 3 hertz (Hz) to 300 gigahertz (GHz+).b. 300 Hz to 300 GHz.c. 3000Hz to 3000 GHz.d. 30 megahertz (MHz) to 300 MHz.
a. 3 hertz (Hz) to 300 gigahertz (GHz+).
What U.S. government agency divides the radio frequency (RF) spectrum into different bands?a. Federal Aviation Agency.b. American National Standard Institute.c. Federal Communications Commission.d. Institute of Electrical & Electronics Engineers, Inc.
c. Federal Communications Commission.
Near-vertical-incidence sky (NVIS) wave operations are most effective when you’re usinga. lower high frequency (HF) frequencies.b. higher HF frequencies.c. medium HF frequencies.d. low takeoff antenna angles.
a. lower high frequency (HF) frequencies.
What frequency band is most susceptible to jamming?a. Low frequency.b. Medium frequency.c. High frequency.d. Very high frequency.
c. High frequency.
What frequency bands does the MILSTAR satellite system use?a. High frequency (HF) and ultrahigh frequency (UHF).b. Super-high frequency (SHF) and extremely high frequency (EHF).c. Very high frequency (VHF) and SHF.d. VHF and UHF.
b. Super-high frequency (SHF) and extremely high frequency (EHF).
The main very high frequency (VHF)/ultra high frequency (UHF) communicationsemphasis is ona. long range deployable communications.b. short range fixed communications.c. emergency communications.d. air-ground communications.
d. air-ground communications.
Super high frequency (SHF)/extremely high frequency (EHF) range is limited toa. scattering.b. line-of-sight (LOS).c. Earth’s conductivity.d. atmospheric absorption.
b. line-of-sight (LOS).
In a move to overcome the limited range of forward propagation by tropospheric scatter (FPTS) without requiring many costly relay systems, what was developed?a. Optical horizon radar.b. Satellite communications.c. Microwave communications.d. Line-of-sight (LOS) communications.
b. Satellite communications.
Why isn’t very high frequency (VHF) normally used for satellite communications?a. The frequency is too low.b. The frequency is too high.c. Ionospheric refraction can occur.d. The rate of absorption is too great.
a. The frequency is too low.
When comparing the radio and optical horizons, which one is farther away and by what percent?a. Optical; 15.b. Radio; 15.c. Optical; 33.d. Radio; 33.
d. Radio; 33.
When K is greater than 4/3, the radio horizon willa. decrease, then increase.b. remain the same.c. decrease.d. increase.
A radio wave originated at a center source in free space. If the field strength at one mile from the source has a field strength of 100 microvolts per meter, what is the field strength at two miles?a. 25 microvolts per meter.b. 50 microvolts per meter.c. 100 microvolts per meter.d. 200 microvolts per meter.
b. 50 microvolts per meter.
Any military action involving the use of the electromagnetic (EM) spectrum to includedirected energy to attack an enemy is calleda. electronic support (ES).b. electronic warfare (EW).c. electromagnetic pulse (EP).d. electromagnetic interference (EI).
b. electronic warfare (EW).
Which is not an example of electronic protection (EP)?a. Frequency agility in a radio.b. Communications intelligence.c. Electronic and material shielding for systems.d. Process to counter meaconing, interference, jamming, and intrusion.
b. Communications intelligence.
Which electronic warfare (EW) component responds to taskings to search for, intercept, identify, and locate intentional and unintentional sources of radiated energy?a. Electronic attack (EA).b. Electronic control (EC).c. Electronic support (ES).d. Electronic protection (EP).
c. Electronic support (ES).
Electromagnetic (EM) deception as it applies to electronic warfare (EW) isa. controlling the information an enemy receives.b. the elimination of some or all of an adversary’s electronic defenses.c. the deliberate radiation of EM energy intended to convey misleading information to an enemy.d. degrading or interfering with the enemy’s use of the EM spectrum to limit the enemy’s combatcapabilities.
c. the deliberate radiation of EM energy intended to convey misleading information to an enemy.
What is the process of unscrambling encrypted information so that it is intelligible?a. Decryption.b. Encryption.c. Cryptography.d. Cryptanalysis.
How many selectable traffic key slots does the KG–84A have?a. 1.b. 2.c. 4.d. 8.
Which switch on the KY–57 VINSON zeroizes channels one through five?a. Fill.b. Mode.c. Power.d. Volume.
The common name for the method of changing the encryption keys over the radio channel in a two-way radio system is calleda. over-the-air-rekeying (OTAR).b. Asymmetric.c. symmetric.d. off-line.
a. over-the-air-rekeying (OTAR).
Centralized control of encryption keys will not reducea. procedural problems.b. operational problems.c. security problems.d. safety problems.
d. safety problems.
In frequency hopping (FH) operation, the interval at which each transmitter remains on a given frequency for a specific time is known as thea. dwell time.b. hopping rate.c. frequency offset.d. transmitter velocity.
a. dwell time.
Which RT–1523 SINCGARS subassembly removes synchronization and frequency hopping information that is embedded in a receive signal?a. The interleaver.b. The modulator.c. The demodulator.d. The exciter/power amplifier module.
a. The interleaver.
The RT–1523 SINCGARS radio’s time sync and correlator module manipulates control signal outputs during the frequency hopping (FH) mode toa. stop frequency shifts during receive operations.b. shut down reception only during frequency shifts.c. shut down transmission only during frequency shifts.d. shut down reception and transmission during frequency shifts.
d. shut down reception and transmission during frequency shifts.
Concerning HAVE QUICK II communications (MWOD), how long can each word of day (WOD) be used?a. Each WOD is used until it is manually changed.b. For a total of 3 days.c. For 48 hours.d. For 24 hours.
d. For 24 hours.
Which one of the following statement is not a characteristic of the AN/GRC–171B(V)4 transceiver?a. It operates from 116 MHz to 149.975 megahertz (MHz).b. It provides antijam communications in amplitude modulation (AM) and frequency modulation(FM).c. It contains both HAVE QUICK and HAVE QUICK II.d. It can communicate on any one of 7,000 available channels.
a. It operates from 116 MHz to 149.975 megahertz (MHz).
What does the low-pass filter of the AN/GRC–171B(V)4 transceiver perform?a. Image frequency rejection in receive and harmonic attenuation in transmit.b. Image frequency rejection in transmit and harmonic attenuation in receive.c. RF decoupling in transmit and harmonic suppression in receive.d. RF decoupling in receive and harmonic suppression in transmit.
a. Image frequency rejection in receive and harmonic attenuation in transmit.
The output power of the AN/GRC–171B(V)4 transceiver isa. 25 Watts in both amplitude modulation (AM) and frequency modulation (FM).b. 20 Watts in AM, 50 Watts in FM.c. 20 Watts in AM, 20 Watts in FM.d. 50 Watts in narrowband, 25 Watts in wideband.
b. 20 Watts in AM, 50 Watts in FM.
The Joint Tactical Information Distribution System (JTIDS) is commonly referred to asa. Link 4A.b. Link 11.c. Link 16.d. Link 22.
c. Link 16.
Which service uses the Enhanced Position Location Reporting System (EPLRS) to locate and track amphibious assault craft?a. Army.b. Navy.c. Marines.d. Air Force.
What type of network radio does the Air Force use for close air support?a. Single Channel Ground and Airborne Radio System (SCGARS).b. Enhanced Position Location Reporting System (EPLRS).c. Joint Tactical Information Distribution System (JTIDS).d. Situation Awareness Data Link (SADL).
d. Situation Awareness Data Link (SADL).
How many programmable devices can the multiband inter/intra team radio hold?a. 3.b. 5.c. 7.d. 10.
What must the primary and remote annunciators be capable of in an intrusion detection system (IDS)?a. Provide dual line of detection.b. Operate independently of one another.c. Backup power for one another.d. Located within the same area for redundancy.
b. Operate independently of one another.
On a sensor system the annunciation display must be able to differentiate betweena. alarms and tampers.b. alarms and equipment failures.c. tampers and nuisance alarms.d. failed self test and power loss.
a. alarms and tampers.
The interior sensor that operates on a principle of magnetic fields imposed on a reed switch is aa. dual-phenomenology.b. passive infrared sensor.c. balanced magnetic switch.d. ported coaxial cable sensor.
c. balanced magnetic switch.
Which personnel identification device provides positive identification through measurement of biometrics?a. Cardreader personal identification number (PIN) pad.b. Cardreader prompt.c. Hand geometry unit (HGU).d. X-ray machine.
c. Hand geometry unit (HGU).
On the advanced entry control system (AECS), which panel configuration monitors sensors and reports any alarm conditions detected?a. Security.b. Distribution.c. Portal control.d. Intrusion detection.
d. Intrusion detection.
What device on the advanced entry control system (AECS) allows the operator to install, review, modify, and broadcast databases created to all other workstations?a. Enrollment operator workstation.b. System administrator terminal.c. Enrollment master station.d. Security workstation.
b. System administrator terminal.
How many hours of power must the uninterrupted power supply (UPS) in an advanced entry control system (AECS) provide in the event that the station power is lost?a. 4.b. 6.c. 8.d. 10.
Which site configuration was designed to provide coverage for a small geographical area?a. Single-site.b. Multi-site.c. Simulcast.d. Multicast.
What provides the interface between dispatch consoles and the central controller in a trunking system?a. Modems.b. Access control.c. Switching equipment.d. System management computer.
c. Switching equipment.
How many talkgroups can a trunked mobile radio monitor at one time?a. 1.b. 2.c. 3.d. every talkgroup programmed in the radio.
What has the ability to patch different talkgroups together?a. Control station.b. Dispatch console.c. Portable.d. Mobile.
b. Dispatch console.
What Air Force instruction (AFI) requires communications squadrons to maintain“installation warning systems”?a. AFI 10–2501.b. AFI 21–116.c. AFI 33–106.d. AFI 33–118.
a. AFI 10–2501.
What is a common problem with a mass alert system in a deployed environment?a. Low power out.b. Efficiency.c. Cleanliness.d. Reliability.
In the Whelen siren stacks, what size driver does a speaker cell contain?a. 40–watt.b. 60–watt.c. 100–watt.d. 400–watt.
In the Whelen siren cabinet, what controls signal routing and power distribution of thesystem?a. Landline board.b. Control board.c. Motherboard.d. Radio board.
With the Whelen configuration software, which tabs allow you to troubleshoot the system?a. Status and multi-format decoding (MFD).b. Status and dual tone multi-frequency (DTMF).c. Status and radio.d. Status and siren.
b. Status and dual tone multi-frequency (DTMF).
In high frequency (HF) communications, your station’s self address isa. user programmed into your system.b. shared with other members.c. the address of an unprogrammed station.d. the same address of other stations in the net.
a. user programmed into your system.
We define link quality analysis (LQA) asa. reviewing a network station listing and determining which is assigned a clear channel.b. reviewing a network station listing and assigning a channel to each.c. the process of sounding and determining channel clarity.d. the process of calling and determining channel clarity.
c. the process of sounding and determining channel clarity.
What is the maximum power of the AN/PRC–150 in frequency modulation (FM) mode?a. 5 watts.b. 10 watts.c. 15 watts.d. 20 watts.
b. 10 watts.