AvdyneAeroservice:.Element #3H 143-Questions

Element #3H....Good luck!...and remember you will be asked 10 questions from this pool.

(E3H1) What is meant by the term antenna gain?
1. The numerical ratio relating the radiated signal strength of an antenna to that of another antenna.
2. The ratio of the signal in the forward direction to the signal in the back direction.
3. The ratio of the amount of power produced by the antenna compared to the output power of the transmitter.
4. The final amplifier gain minus the transmission line losses (including any phasing lines present).
(E3H2) What is the term for a numerical ratio that relates the performance of one antenna to that of another real or theoretical antenna?
1. Effective radiated power.
2. Antenna gain.
3. Conversion gain.
4. Peak effective power.
(E3H3) What is meant by the term antenna bandwidth?
1. Antenna length divided by the number of elements.
2. The frequency range over which an antenna can be expected to perform well.
3. The angle between the half-power radiation points.
4. The angle formed between two imaginary lines drawn through the ends of the elements.
(E3H4) What is the wavelength of a shorted stub used to absorb even harmonics?
1. 1/2 wavelength.
2. 1/3 wavelength.
3. 1/4 wavelength.
4. 1/8 wavelength.
(E3H5) What is a trap antenna?
1. An antenna for rejecting interfering signals.
2. A highly sensitive antenna with maximum gain in all directions.
3. An antenna capable of being used on more than one band because of the presence of parallel LC networks.
4. An antenna with a large capture area.
(E3H6) What is an advantage of using a trap antenna?
1. It has high directivity in the high-frequency bands.
2. It has high gain.
3. It minimizes harmonic radiation.
4. It may be used for multiband operation.
(E3H7) What is a disadvantage of using a trap antenna?
1. It will radiate harmonics.
2. It can only be used for single band operation.
3. It is too sharply directional at lower frequencies.
4. It must be neutralized.
(E3H8) What is the principle of a trap antenna?
1. Beamwidth may be controlled by non-linear impedances.
2. The traps form a high impedance to isolate parts of the antenna.
3. The effective radiated power can be increased if the space around the antenna "sees" a high impedance.
4. The traps increase the antenna gain.
(E3H9) What is a parasitic element of an antenna?
1. An element polarized 90 degrees opposite the driven element.
2. An element dependent on the antenna structure for support.
3. An element that receives its excitation from mutual coupling rather than from a transmission line.
4. A transmission line that radiates radio-frequency energy.
(E3H10) How does a parasitic element generate an electromagnetic field?
1. By the RF current received from a connected transmission line.
2. By interacting with the earth's magnetic field.
3. By altering the phase of the current on the driven element.
4. By currents induced into the element from a surrounding electric field.
(E3H11) How does the length of the reflector element of a parasitic element beam antenna compare with that of the driven element?
1. It is about 5% longer.
2. It is about 5% shorter.
3. It is twice as long.
4. It is one-half as long.
(E3H12) How does the length of the director element of a parasitic-element beam antenna compare with that of the driven element?
1. It is about 5% longer.
2. It is about 5% shorter.
3. It is one-half as long.
4. It is twice as long.
(E3H13) What is meant by the term radiation resistance for an antenna?
1. Losses in the antenna elements and feed line.
2. The specific impedance of the antenna.
3. An equivalent resistance that would dissipate the same amount of power as that radiated from an antenna.
4. The resistance in the trap coils to received signals.
(E3H14) What are the factors that determine the radiation resistance of an antenna?
1. Transmission line length and height of antenna.
2. The location of the antenna with respect to nearby objects and the length/diameter ratio of the conductors.
3. It is a constant for all antennas since it is a physical constant.
4. Sunspot activity and the time of day.
(E3H15) What is a driven element of an antenna?
1. Always the rearmost element.
2. Always the forwardmost element.
3. The element fed by the transmission line.
4. The element connected to the rotator.
(E3H16) What is the usual electrical length of a driven element in a HF beam antenna?
1. 1/4 wavelength.
2. 1/2 wavelength.
3. 3/4 wavelength.
4. 1 wavelength.
(E3H17) What is the term for an antenna element that is supplied power from a transmitter through a transmission line?
1. Driven element.
2. Director element.
3. Reflector element.
4. Parasitic element.
(E3H18) How is antenna "efficiency" computed?
1. Efficiency = (radiation resistance/transmission resistance) X 100%.
2. Efficiency = (radiation resistance/total resistance) X 100%.
3. Efficiency = (total resistance/radiation resistance) X 100%.
4. Efficiency = (effective radiated power/transmitter output) X 100%.
(E3H19) What is the term for the ratio of the radiation resistance of an antenna to the total resistance of the system?
1. Effective radiated power.
2. Radiation conversion loss.
3. Antenna efficiency.
4. Beamwidth.
(E3H20) What is included in the total resistance of an antenna system?
1. Radiation resistance plus space impedance.
2. Radiation resistance plus transmission resistance.
3. Transmission line resistance plus radiation resistance.
4. Radiation resistance plus ohmic resistance.
(E3H21) How can the antenna efficiency of a HF grounded vertical antenna be made comparable to that of a half-wave antenna?
1. By installing a good ground radial system.
2. By isolating the coax shield from ground.
3. By shortening the vertical.
4. By lengthening the vertical.
(E3H22) Why does a half-wave antenna operate at very high efficiency?
1. Because it is non-resonant.
2. Because the conductor resistance is low compared to the radiation resistance.
3. Because earth-induced currents add to its radiated power.
4. Because it has less corona from the element ends than other types of antennas.
(E3H23) What is a folded dipole antenna?
1. A dipole that is one-quarter wavelength long.
2. A ground plane antenna.
3. A dipole whose ends are connected by another one-half wavelength piece of wire.
4. A fictional antenna used in theoretical discussions to replace the radiation resistance.
(E3H24) How does the bandwidth of a folded dipole antenna compare with that of a simple dipole antenna?
1. It is 0.707 times the simple dipole bandwidth.
2. It is essentially the same.
3. It is less than 50% that of a simple dipole.
4. It is greater.
(E3H25) What is the input terminal impedance at the center of a folded dipole antenna?
1. 300 ohms.
2. 72 ohms.
3. 50 ohms.
4. 450 ohms.
(E3H26) What is the meaning of the term "velocity factor" of a transmission line?
1. The ratio of the characteristic impedance of the line to the terminating impedance.
2. The index of shielding for coaxial cable.
3. The velocity of the wave on the transmission line multiplied by the velocity of light in a vacuum.
4. The velocity of the wave on the transmission line divided by the velocity of light in a vacuum.
(E3H27) What is the term for the ratio of actual velocity at which a signal travels through a line to the speed of light in a vacuum?
1. Velocity factor.
2. Characteristic impedance.
3. Surge impedance.
4. Standing wave ratio.
(E3H28) What is the velocity factor for non-foam dielectric 50 or 75 ohm flexible coaxial cable such as RG 8, 11, 58 and 59?
1. 2.70.
2. 0.66.
3. 0.30.
4. 0.10.
(E3H29) What determines the velocity factor in a transmission line?
1. The termination impedance.
2. The line length.
3. Dielectrics in the line.
4. The center conductor resistivity.
E3H30) Why is the physical length of a coaxial cable transmission line shorter than its electrical length?
1. Skin effect is less pronounced in the coaxial cable.
2. RF energy moves slower along the coaxial cable.
3. The surge impedance is higher in the parallel feed line.
4. The characteristic impedance is higher in the parallel feed line.
(E3H31) What would be the physical length of a typical coaxial transmission line that is electrically one-quarter wavelength long at 14.1MHz?
1. 20 meters.
2. 3.51 meters.
3. 2.33 meters.
4. 0.25 meters.
(E3H32) What would be the physical length of a typical coaxial transmission line that is electrically one-quarter wavelength long at 7.2 MHz?
1. 10.5 meters.
2. 6.88 meters.
3. 24 meters.
4. 50 meters.
(E3H33) What is the physical length of a parallel antenna feedline that is electrically one-half wavelength long at 14.10 MHz? (assume a velocity factor of 0.82).
1. 15 meters.
2. 24.3 meters.
3. 8.7 meters.
4. 70.8 meters.
(E3H34) What is the physical length of a twin lead transmission feedline at 36.5 MHz? (assume a velocity factor of 0.80).
1. Electrical length times 0.8.
2. Electrical length divided by 0.8.
3. 80 meters.
4. 160 meters.
(E3H35) In a half-wave antenna, where are the current nodes?
1. At the ends.
2. At the center.
3. Three-quarters of the way from the feed point toward the end.
4. One-half of the way from the feed point toward the end.
(E3H36) In a half-wave antenna, where are the voltage nodes?
1. At the ends.
2. At the feed point.
3. Three-quarters of the way from the feed point toward the end.
4. One-half of the way from the feed point toward the end.
(E3H37) At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna?
1. Equal voltage and current.
2. Minimum voltage and maximum current.
3. Maximum voltage and minimum current.
4. Minimum voltage and minimum current.
(E3H38) At the center of a half-wave antenna, what values of voltage and current exist compared to the remainder of the antenna?
1. Equal voltage and current.
2. Maximum voltage and minimum current.
3. Minimum voltage and minimum current.
4. Minimum voltage and maximum current.
(E3H39) What happens to the base feed point of a fixed length mobile antenna as the frequency of operation is lowered?
1. The resistance decreases and the capacitive reactance decreases.
2. The resistance decreases and the capacitive reactance increases.
3. The resistance increases and the capacitive reactance decreases.
4. The resistance increases and the capacitive reactance increases.
(E3H40) Why should an HF mobile antenna loading coil have a high ratio of reactance to resistance?
1. To swamp out harmonics.
2. To maximize losses.
3. To minimize losses.
4. To minimize the Q.
(E3H41) Why is a loading coil often used with an HF mobile antenna?
1. To improve reception.
2. To lower the losses.
3. To lower the Q.
4. To tune out the capacitive reactance.
(E3H42) For a shortened vertical antenna, where should a loading coil be placed to minimize losses and produce the most effective performance?
1. Near the center of the vertical radiator.
2. As low as possible on the vertical radiator.
3. As close to the transmitter as possible.
4. At a voltage node.
(E3H43) What happens to the bandwidth of an antenna as it is shortened through the use of loading coils?
1. It is increased.
2. It is decreased.
3. No change occurs.
4. It becomes flat.
(E3H44) What type of antenna is used in an aircraft's Instrument Landing System (ILS) glideslope installation?
1. A vertically polarized antenna that radiates an omnidirectional antenna pattern.
2. A balanced loop reception antenna.
3. A folded dipole reception antenna.
4. An electronically steerable phased-array antenna that radiates a directional antenna pattern.
(E3H45) What is an advantage of using top loading in a shortened HF vertical antenna?
1. Lower Q.
2. Greater structural strength.
3. Higher losses.
4. Improved radiation efficiency.
(E3H46) What is an isotropic radiator?
1. A hypothetical, omnidirectional antenna.
2. In the northern hemisphere, an antenna whose directive pattern is constant in southern directions.
3. An antenna high enough in the air that its directive pattern is substantially unaffected by the ground beneath it.
4. An antenna whose directive pattern is substantially unaffected by the spacing of the elements.
(E3H47) When is it useful to refer to an isotropic radiator?
1. When comparing the gains of directional antennas.
2. When testing a transmission line for standing wave ratio.
3. When (in the northern hemisphere) directing the transmission in a southerly direction.
4. When using a dummy load to tune a transmitter.
(E3H48) What theoretical reference antenna provides a comparison for antenna measurements?
1. Quarter-wave vertical.
2. Yagi-Uda array.
3. Bobtail curtain.
4. Isotropic radiator.
(E3H49) What purpose does an isotropic radiator serve?
1. It is used to compare signal strengths (at a distant point) of different transmitters.
2. It is used as a reference for antenna gain measurements.
3. It is used as a dummy load for tuning transmitters.
4. It is used to measure the standing-wave-ratio on a transmission line.
(E3H50) How much gain does a 1/2-wavelength dipole have over an isotropic radiator?
1. About 1.5 dB.
2. About 2.1 dB.
3. About 3.0 dB.
4. About 6.0 dB.
(E3H51) How much gain does an antenna have over a 1/2-wavelength dipole when it has 6 dB gain over an isotropic radiator?
1. About 3.9 dB.
2. About 6.0 dB.
3. About 8.1 dB.
4. About 10.0 dB.
(E3H52) How much gain does an antenna have over a 1/2-wavelength dipole when it has 12 dB gain over an isotropic radiator?
1. About 6.1 dB.
2. About 9.9 dB.
3. About 12.0 dB.
4. About 14.1 dB.
(E3H53) What is the antenna pattern for an isotropic radiator?
1. A figure-8.
2. A unidirectional cardioid.
3. A parabola.
4. A sphere.
(E3H54) What type of directivity pattern does an isotropic radiator have?
1. A figure-8.
2. A unidirectional cardioid.
3. A parabola.
4. A sphere.
(E3H55) What factors determine the receiving antenna gain required at a station in earth operation?
1. Height, transmitter power and antennas of satellite.
2. Length of transmission line and impedance match between receiver and transmission line.
3. Preamplifier location on transmission line and presence or absence of RF amplifier stages.
4. Height of earth antenna and satellite orbit.
(E3H56) What factors determine the EIRP required by a station in earth operation?
1. Satellite antennas and height, satellite receiver sensitivity.
2. Path loss, earth antenna gain, signal-to-noise ratio.
3. Satellite transmitter power and orientation of ground receiving antenna.
4. Elevation of satellite above horizon, signal-to-noise ratio, satellite transmitter power.
(E3H57) What factors determine the EIRP required by a station in telecommand operation?
1. Path loss, earth antenna gain, signal-to-noise ratio.
2. Satellite antennas and height, satellite receiver sensitivity.
3. Satellite transmitter power and orientation of ground receiving antenna.
4. Elevation of satellite above horizon, signal-to-noise ratio, satellite transmitter power.
(E3H58) How does the gain of a parabolic dish type antenna change when the operating frequency is doubled?
1. Gain does not change.
2. Gain is multiplied by 0.707.
3. Gain increases 6 dB.
4. Gain increases 3 dB.
(E3H59) What happens to the beamwidth of an antenna as the gain is increased?
1. The beamwidth increases geometrically as the gain is
  increased.
2. The beamwidth increases arithmetically as the gain is
  increased.
3. The beamwidth is essentially unaffected by the gain of
  the antenna.
4. The beamwidth decreases as the gain is increased.
(E3H60) What is the beamwidth of a symmetrical pattern antenna with a gain of 20 dB as compared to an isotropic radiator?
1. 10.1 degrees.
2. 20.3 degrees.
3. 45.0 degrees.
4. 60.9 degrees.
(E3H61) What is the beamwidth of a symmetrical pattern antenna with a gain of 30 dB as compared to an isotropic radiator?
1. 3.2 degrees.
2. 6.4 degrees.
3. 37 degrees.
4. 60.4 degrees.
(E3H62) What is the beamwidth of a symmetrical pattern antenna with a gain of 15 dB as compared to an isotropic radiator?
1. 72 degrees.
2. 52 degrees.
3. 36.1 degrees.
4. 3.61 degrees.
(E3H63) What is the beamwidth of a symmetrical pattern antenna with a gain of 12 dB as compared to an isotropic radiator?
1. 34.8 degrees.
2. 45.0 degrees.
3. 58.0 degrees.
4. 51.0 degrees.
(E3H64) How is circular polarization produced using linearly-polarized antennas?
1. Stack two yagis, fed 90 degrees out of phase, to form an array with the respective elements in parallel planes.
2. Stack two yagis, fed in phase, to form an array with the respective elements in parallel planes.
3. Arrange two yagis perpendicular to each other, with the driven elements in the same plane, fed 90 degrees out of phase.
4. Arrange two yagis perpendicular to each other, with the driven elements in the same plane, fed in phase.
(E3H65) Why does an antenna system for earth operation (for communications through a satellite) need to have rotators for both azimuth and elevation control?
1. In order to point the antenna above the horizon to avoid terrestrial interference.
2. Satellite antennas require two rotators because they are so large and heavy.
3. In order to track the satellite as it orbits the earth.
4. The elevation rotator points the antenna at the satellite and the azimuth rotator changes the antenna polarization.
(E3H66) What term describes a method used to match a high-impedance transmission line to a lower impedance antenna by connecting the line to the driven element in two places, spaced a fraction of a wavelength on each side of the driven element center?
1. The gamma matching system.
2. The delta matching system.
3. The omega matching system.
4. The stub matching system.
(E3H67) What term describes an unbalanced feed system in which the driven element is fed both at the center of that element and a fraction of a wavelength to one side of center?
1. The gamma matching system.
2. The delta matching system.
3. The omega matching system.
4. The stub matching system.
(E3H68) What term describes a method of antenna impedance matching that uses a short section of transmission line connected to the antenna feed line near the antenna and perpendicular to the feed line?
1. The gamma matching system.
2. The delta matching system.
3. The omega matching system.
4. The stub matching system.
(E3H69) What kind of impedance does a 1/8-wavelength transmission line present to a generator when the line is shorted at the far end?
1. A capacitive reactance.
2. The same as the characteristic impedance of the line.
3. An inductive reactance.
4. The same as the input impedance to the final generator stage.
(E3H70) What kind of impedance does a 1/8-wavelength transmission line present to a generator when the line is open at the far end?
1. The same as the characteristic impedance of the line.
2. An inductive reactance.
3. A capacitive reactance.
4. The same as the input impedance of the final generator stage.
(E3H71) What kind of impedance does a 1/4-wavelength transmission line present to a generator when the line is shorted at the far aid?
1. A very high impedance.
2. A very low impedance.
3. The same as the characteristic impedance of the transmission line.
4. The same as the generator output impedance.
(E3H72) What kind of impedance does a 1/4-wavelength transmission line present to a generator when the line is open at the far end?
1. A very high impedance.
2. A very low impedance.
3. The same as the characteristic impedance of the line.
4. The same as the input impedance to the final generator stage.
(E3H73) What kind of impedance does a 3/8-wavelength transmission line present to a generator when the line is shorted at the far aid?
1. The same as the characteristic impedance of the line.
2. An inductive reactance.
3. A capacitive reactance.
4. The same as the input impedance to the final generator stage.
(E3H74) What kind of impedance does a 3/8-wavelength transmission line present to a generator when the line is open at the far end?
1. A capacitive reactance.
2. The same as the characteristic impedance of the line.
3. An inductive reactance.
4. The same as the input impedance to the final generator stage.
(E3H75) What kind of impedance does a 1/2-wavelength transmission line present to a generator when the line is shorted at the far end?
1. A very high impedance.
2. A very low impedance.
3. The same as the characteristic impedance of the line.
4. The same as the output impedance of the generator.
(E3H76) What kind of impedance does a 1/2-wavelength transmission line present to a generator when the line is open at the far end?
1. A very high impedance.
2. A very low impedance.
3. The same as the characteristic impedance of the line.
4. The same as the output impedance of the generator.
(E3H77) What is the term used for an equivalent resistance that would dissipate the same amount of energy as that radiated from an antenna?
1. Space resistance.
2. Loss resistance.
3. Transmission line loss.
4. Radiation resistance.
(E3H78) Why is the value of the radiation resistance of an antenna important?
1. Knowing the radiation resistance makes it possible to match impedances for maximum power transfer.
2. Knowing the radiation resistance makes it possible to measure the near-field radiation density from a transmitting antenna.
3. The value of the radiation resistance represents the front-to-side ratio of the antenna.
4. The value of the radiation resistance represents the front-to-back ratio of the antenna.
(E3H79) Adding parasitic elements to an antenna will:
1. Decrease its directional characteristics.
2. Decrease its sensitivity.
3. Increase its directional characteristics.
4. Increase its sensitivity.
(E3H80) What ferrite rod device prevents the formation of reflected waves on a waveguide transmission line?
1. Reflector.
2. Isolator.
3. Wave-trap.
4. SWR refractor.
(E3H81) Frequencies most affected by knife-edge refraction are:
1. Low and medium frequencies.
2. High frequencies.
3. Very high and ultra high frequencies.
4. 100 kHz. to 3.0 MHz.
(E3H82) When measuring I and V along a 1/2 wave Hertz antenna, where would you find the points where I and V are maximum and minimum?
1. V and I are high at the ends.
2. V and I are high in the middle.
3. V and I are uniform throughout the antenna.
4. V is maximum at both ends, I is maximum in the middle.
(E3H83) To increase the resonant frequency of a 1/4 wavelength antenna:
1. Add a capacitor.
2. Lower capacitor value.
3. Cut antenna.
4. Add an inductor.
(E3H84) Why are concentric transmission lines sometimes filled with nitrogen?
1. Reduces resistance at high frequencies.
2. Prevent water damage underground.
3. Keep moisture out and prevent oxidation.
4. Reduce microwave line losses.
(E3H85) A vertical 1/4 wave antenna receives signals:
1. In the microwave band.
2. In one vertical direction.
3. In one horizontal direction.
4. Equally from all horizontal directions.
(E3H86) Which of the following represents the best standing wave ratio (SWR)?
1. 1:1.
2. 1:1.5.
3. 1:3.
4. 1:4.
(E3H87) What is the purpose of stacking elements on an antenna?
1. Sharper directional pattern.
2. Increased gain.
3. Improved bandpass.
4. All of these.
(E3H88) What type of antenna is used in an aircraft's Instrument Landing System (ILS) marker beacon installation?
1. An electronically steerable phased-array antenna that radiates a directional antenna pattern.
2. A folded dipole reception antenna.
3. A balanced loop reception antenna.
4. A horizontally polarized antenna that radiates an omnidirectional antenna pattern.
(E3H89) On a half-wave Hertz antenna:
1. Voltage is maximum at both ends and current is maximum at the center of the antenna.
2. Current is maximum at both ends and voltage in the center.
3. Voltage and current are uniform throughout the antenna.
4. Voltage and current are high at the ends.
(E3H90) What type of antenna is designed for minimum radiation?
1. Dummy antenna.
2. Quarter-wave antenna.
3. Half-wave antenna.
4. Directional antenna.
(E3H91) What type of antenna is used in an aircraft's Very High Frequency Omnidirectional Range (VOR) and Localizer (LOC) installations?
1. A vertically polarized antenna that radiates an omnidirectional antenna pattern.
2. A folded dipole reception antenna.
3. A balanced loop transmission antenna.
4. A horizontally polarized omnidirection reception antenna.
(E3H92) Adding parasitic elements to a quarter-wavelength antenna will:
1. Reduce its directional characteristics.
2. Increase its directional characteristics.
3. Increase its sensitivity.
4. Increase its directional characteristics and increase its sensitivity.
(E3H93) Ignoring line losses, voltage at a point on a transmission line without standing waves is:
1. Equal to the product of the line current and impedance.
2. Equal to the product of the line current and power factor.
3. Equal to the product of the line current and the surge impedance.
4. Zero at both ends.
(E3H94) Stacking antenna elements:
1. Will suppress odd harmonics.
2. Decrease signal to noise ratio.
3. Increases sensitivity to weak signals.
4. Increases selectivity.
(E3H95) What allows microwaves to pass in only one direction?
1. RF emitter.
2. Ferrite isolator.
3. Capacitor.
4. Varactor-triac.
(E3H96) What would be added to make a receiving antenna more directional?
1. Inductor.
2. Capacitor.
3. Parasitic elements.
4. Height.
(E3H97) Nitrogen is placed in transmission lines to:
1. Improve the "skin-effect" of microwaves.
2. Reduce arcing in the line.
3. Reduce the standing wave ratio of the line.
4. Prevent moisture from entering the line.
(E3H98) Neglecting line losses, the voltage at any point along a transmission line, having no standing waves, will be equal to the:
1. Transmitter output.
2. Product of the line voltage and the surge impedance of the line.
3. Product of the line current and the surge impedance of the line.
4. Product of the resistance and surge impedance of the line.
(E3H99) Adding a capacitor in series with a Marconi antenna:
1. Increases the antenna circuit resonant frequency.
2. Decreases the antenna circuit resonant frequency.
3. Blocks the transmission of signals from the antenna.
4. Increases the power handling capacity of the antenna.
(E3H100) An antenna is carrying an unmodulated signal, when 100% modulation is impressed, the antenna current:
1. Goes up 50%.
2. Goes down one half.
3. Stays the same.
4. Goes up 22.5%.
(E3H101) An excited 1/2 wavelength antenna produces:
1. Residual fields.
2. An electro-magnetic field only.
3. Both electro-magnetic and electro-static fields.
4. An electro-flux field sometimes.
(E3H102) An antenna which intercepts signals equally from all horizontal directions is:
1. Parabolic.
2. Vertical loop.
3. Horizontal marconi.
4. Vertical 1/4 wave.
(E3H103) A Loop-antenna:
1. Is bi-directional.
2. Is usually vertical.
3. Is more often used as a receiving antenna.
4. Any of these.
(E3H104) Referred to the fundamental frequency, a shorted stub line attached to the transmission line to absorb even harmonics could have a wavelength of:
1. 1.41 wavelengths.
2. 1/2 wavelengths.
3. 1/4 wavelengths.
4. 1/6 wavelengths.
(E3H105) Nitrogen gas in concentric RF transmission lines is used to:
1. Keep moisture out.
2. Prevent oxidation.
3. Act as an insulator.
4. Keep moisture out and prevent oxidation.
(E3H106) "Stacking" elements on an antenna:
1. Makes for better reception.
2. Makes for poorer reception.
3. Decreases antenna current.
4. Decreases directivity.
(E3H107) What type of antenna is attached to an aircraft's Mode C transponder installation and used to receive 1030 MHz interrogation signals from the Air Traffic Control Radar Beacon System (ATCRBS)?
1. An L-band monopole blade-type omnidirectional antenna.
2. An electronically steerable phased-array directional antenna.
3. A folded dipole reception antenna.
4. An internally mounted, mechanically rotatable loop antenna.
(E3H108) The parasitic elements on a receiving antenna:
1. Increase its directivity.
2. Decrease its directivity.
3. Have no effect on its impedance.
4. Make it more nearly omnidirectional.
(E3H109) What type of antenna is attached to an aircraft's Mode S transponder installation and used to receive 1030 MHz interrogation signals from the Air Traffic Control Radar Beacon System (ATCRBS)?
1. An L-band monopole blade-type omnidirectional antenna.
2. An electronically steerable phased-array directional antenna.
3. A folded dipole reception antenna.
4. An internally mounted, mechanically rotatable loop antenna.
(E3H110) The resonant frequency of a Hertz antenna can be lowered by:
1. Lowering the frequency of the transmitter.
2. Placing a condenser in series with the antenna.
3. Placing a resistor in series with the antenna.
4. Placing an inductance in series with the antenna.
(E3H111) Parasitic elements are useful in a receiving antenna for:
1. Increasing directivity.
2. Increasing selectivity.
3. Increasing sensitivity.
4. Increasing directivity and increasing sensitivity.
(E3H112) What type of antenna radiates the 1030 MHz interrogation signals from an aircraft's Mode S Traffic alert and Collision Avoidance System (TCAS) installation?
1. An L-band monopole blade-type omnidirectional antenna.
2. An electronically steerable phased-array directional antenna.
3. A folded dipole antenna.
4. An internally mounted, mechanically rotatable loop antenna.
(E3H113) Concerning shipboard satellite dish antenna systems, azimuth is:
1. Vertical aiming of the antenna.
2. Horizontal aiming of the antenna.
3. 0-90 degrees.
4. North to east.
(E3H114) What is the effect of adding a capacitor in series to an antenna?
1. Resonant frequency will decrease.
2. Resonant frequency will increase.
3. Resonant frequency will remain same.
4. Electrical length will be longer.
(E3H115) If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter?
1. 70 watts.
2. 50 watts.
3. 25 watts.
4. 6 watts.
(E3H116) Waveguides are:
1. Used exclusively in high frequency power supplies.
2. Ceramic couplers attached to antenna terminals.
3. High-pass filters used at low radio frequencies.
4. Hollow metal conductors used to carry high frequency current.
(E3H117) What type of antenna pattern is radiated from a phased-array directional antenna when transmitting the PI or P3 Pulse Position Modulated pulses in a Mode S interrogation signal of an aircraft's Traffic alert and Collision Avoidance System (TCAS) installation?
1. A 1090 MHz directional pattern.
2. A 1030 MHz omnidirectional pattern.
3. A 1090 MHz omnidirectional pattern.
4. A 1030 MHz directional pattern.
(E3H118) A 520 kHz signal is fed to a 1/2 wave Hertz antenna. The fifth harmonic will be:
1. 2.65MHz.
2. 2650kHz.
3. 2600 KHz.
4. 104kHz.
(E3H119) When a capacitor is connected in series with a Marconi antenna:
1. An inductor of equal value must be added.
2. No change occurs to antenna.
3. Antenna open circuit stops transmission.
4. Antenna resonant frequency increases.
(E3H120) How do you increase the electrical length of an antenna?
1. Add an inductor in parallel.
2. Add an inductor in series.
3. Add a capacitor in series.
4. Add a resistor in series.
(E3H121) A coaxial cable has 7 dB of reflected power when the input is 5 watts. What is the output of the transmission line?
1. 5 watts.
2. 2.5 watts.
3. 1.25 watts.
4. 1 watt.
(E3H122) What is the 7th harmonic of 450 kHz when fed through a ¼ wavelength vertical antenna?
1. 3150 Hz.
2. 3150 MHz.
3. 787.5 kHz.
4. 3.15 MHz.
(E3H123) What is the 5th harmonic of a 450 kHz transmitter carrier fed to a ¼ wave antenna?
1. 562.5 MHz.
2. 1125 kHz.
3. 2250 MHz.
4. 2.25 MHz.
(E3H124) Waveguide construction:
1. Should not use silver plating.
2. Should not use copper.
3. Should have short vertical runs.
4. Should not have long horizontal runs.
(E3H125) What type of antenna radiates the 1090 MHz "squirter" signals from an aircraft's Mode S transponder installation of the Air Traffic Control Radar Beacon System (ATCRBS)?
1. An L-band monopole blade-type omnidirectional antenna.
2. An electronically steerable phased-array antenna radiating an omnidirectional pattern.
3. A folded dipole antenna.
4. An internally mounted, mechanically rotatable loop antenna.
(E3H126) To lengthen an antenna electrically, add a:
1. Coil.
2. Resistor.
3. Battery:
4. Conduit.
(E3H127) How do you electrically decrease the length of an antenna?
1. Add an inductor in series.
2. Add a capacitor in series.
3. Add an inductor in parallel.
4. Add a resistor in series.
(E3H128) If the length of an antenna is changed from 1.5 feet to 1.6 feet its resonant frequency will:
1. Decrease.
2. Increase.
3. Be 6.7% higher.
4. Be 6% lower.
(E3H129) To couple energy into and out of a waveguide:
1. Use wide copper sheeting.
2. Use an LC circuit.
3. Use capacitive coupling.
4. Use a thin piece of wire as an antenna.
(E3H130) An isolator:
1. Acts as a buffer between a microwave oscillator coupled to a waveguide.
2. Acts as a buffer to protect a microwave oscillator from variations in line load changes.
3. Shields UHF circuits from RF transfer.
4. Acts as a buffer between a microwave oscillator coupled to a waveguide and acts as a buffer to protect a microwave oscillator from variations in line load changes.
(E3H131) A high SWR creates losses in transmission lines. A high standing wave ratio might be caused by:
1. Improper turns ratio between primary and secondary in the plate tank transformer.
2. Screen grid current flow.
3. An antenna electrically too long for its frequency.
4. An impedance mismatch.
(E3H132) A properly installed shunt-fed, 1/4 wave Marconi antenna:
1. Has zero resistance to ground.
2. Has high resistance to ground.
3. Should be cut to 1/2 wave.
4. Should not be shunt-fed.
(E3H133) When a capacitor is connected in series with a Marconi antenna:
1. An inductor of equal value must be added.
2. No change occurs to antenna.
3. Antenna open circuit stops transmission.
4. Antenna resonant frequency increases.
(E3H134) When excited by RF, a half-wave antenna will radiate:
1. A space wave.
2. A ground wave.
3. Electromagnetic fields.
4. Both electromagnetic and electrostatic fields.
(E3H135) Wave guides are:
1. Used exclusively in high frequency power supplies.
2. Ceramic couplers attached to antenna terminals.
3. High pass filters used at low radio frequencies.
4. Hollow metal conductors used to carry high frequency current.
(E3H136) A 520 kHz signal is fed to a 1/2 wave Hertz antenna. The fifth harmonic will be:
1. 2.65 MHz.
2. 2650 kHz.
3. 2600 KHz.
4. 1300 kHz.
(E3H137) The voltage produced in a receiving antenna is:
1. Out of phase with the current if connected properly.
2. Out of phase with the current if cut to 1/3 wavelength.
3. Variable depending on the station's SWR.
4. Always proportional to the received field strength.
(E3H138) A properly connected transmission line:
1. Is grounded at the transmitter end.
2. Is cut to a harmonic of the carrier frequency.
3. Is cut to an even harmonic of the carrier frequency.
4. Has a SWR as near as 1:1 as possible.
(E3H139) Conductance takes place in a waveguide:
1. By interelectron delay.
2. Through electrostatic field reluctance.
3. In the same manner as a transmission line.
4. Through electromagnetic and electrostatic fields in the walls of the waveguide.
(E3H140) Concerning shunt-fed 1/4 wavelength Marconi antenna:
1. DC resistance of the antenna to ground is zero.
2. RF resistance from antenna feed point to ground is zero.
3. Harmonic radiation is zero under all conditions.
4. It must be grounded at both feed and far ends.
(E3H141) What type of antenna pattern is radiated from a phased-array directional antenna when transmitting the P2 Side Lobe Suppression (SLS) pulse in a Mode S interrogation signal of an aircraft's Traffic alert and Collision Avoidance System (TCAS) installation?
1. A 1090 MHz directional pattern.
2. A 1030 MHz omnidirectional pattern.
3. A 1090 MHz omnidirectional pattern.
4. A 1030 MHz directional pattern.
(E3H142) If a 3/4 wavelength transmission is shortened at one end, impedance at the open will be:
1. Zero.
2. Infinite.
3. Decreased.
4. Increased.
(E3H143) A dummy antenna is a:
1. Non-directional receiver antenna.
2. Wide bandwidth directional receiver antenna.
3. Transmitter test antenna designed for minimum radiation.
4. Transmitter non-directional narrow-band antenna.

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