- The velocity of propagation of radio frequency energy in free space
is:
A. 300 000 kilometers per second.
B. 3000 kilometers per second.
C. 150 kilometers per second.
D. 186 000 kilometers per second.
- The speed of a radio wave:
A. is infinite in space
B. is the same as the speed of light.
C. is always less than half the speed of light.
D. varies directly with frequency.
- Polarization of an antenna is determined by:
A. by the height of the antenna.
B. the electric field.
C. the type of antenna.
D. the magnetic field.
- What does horizontal wave polarization mean?
A. The electric and magnetic lines of force of a radio wave are perpendicular
to the earth’s surface.
B. The electric lines of force of a radio wave are perpendicular to the earth’s
surface.
C. The electric lines of force of a radio wave are parallel to the earth’s
surface.
D. The magnetic lines of force of a radio wave are parallel to the earth’s
surface.
- What does vertical wave polarization mean?
A. The magnetic lines of force of a radio wave are perpendicular to the
earth's surface.
B. The electric lines of force of a radio wave are perpendicular to the earth’s
surface.
C. The electric and magnetic lines of force of a radio wave are parallel to the
earth's surface.
D. The electric lines of force of a radio wave are parallel to the earth’s
surface.
- An isotropic antenna is a:
A. hypothetical point source.
B. Infinitely long piece of wire.
C. Dummy load.
D. Half-wave reference dipole.
- What is the antenna radiation pattern for an isotropic radiator?
A. A parabola.
B. A cardioid.
C. A unidirectional cardioid.
D. A sphere.
- If an electromagnetic wave leaves an antenna vertically polarized, it will arrive at
the receiving antenna, by ground wave:
A. polarized at right angles to the original.
B. Vertically polarized.
C. Horizontally polarized.
D. Polarized in any plane.
- The wavelength for a frequency of 25 MHz is:
A. 15 meters (49.2 ft.).
B. 4 meters (13.1 ft.).
C. 12 meters (39.4 ft.).
D. 32 meters (105 ft.).
- The wavelength corresponding to a frequency of 2 MHz is:
A. 360 meters (1181 ft.).
B. 150 meters (492 ft.).
C. 1500 meters (4921 ft.).
D. 30 meters (98 ft.).
- If you made a half-wavelength dipole for 28.550 MHz, how long would
it be?
A. 10.5 meters (34.37 ft.).
B. 28.55 meters (93.45 ft.).
C. 5.08 meters (16.62 ft.).
D. 10.16 meters (33.26 ft.).
- A dipole transmitting antenna, placed so that the ends are pointing North/South,
radiates:
A. mostly north and south.
B. mostly to the south.
C. equally in all directions.
D. mostly east and west.
- What electromagnetic wave polarization does a half-wavelength antenna have
when it is perpendicular to the earth’s surface?
A. Circular.
B. Horizontal.
C. Parabolic.
D. Vertical.
- A dipole antenna will emit a vertically polarized wave if it is:
A. fed with the correct type of RF.
B. too near to the ground.
C. parallel with the ground.
D. mounted vertically.
- At the ends of a suspended antenna wire, insulators are used. These act to:
A. limit the electrical length of the antenna.
B. increase the effective antenna length.
C. allow the antenna to be more easily held vertically.
D. prevent any loss of radio waves by the antenna.
- The property of an antenna, which defines the range of frequencies to which it
will respond, is called its:
A. bandwidth.
B. front-to-back ratio.
C. impedance.
D. polarization.
- Approximately how much gain does a half-wave dipole have over an isotropic
radiator?
A. 1.5 dB.
B. 3.0 dB.
C. 6.0 dB.
D. 2.1 dB.
- What is meant by antenna bandwidth?
A. Antenna length divided by the number of elements.
B. The angle between the half-power radiation points.
C. The angle formed between two imaginary lines drawn through the ends of
the elements.
D. The frequency range over which the antenna may be expected to perform
well.
- In free space, what is the radiation characteristic of a half-wave dipole?
A. Minimum radiation from the ends, maximum broadside.
B. Maximum radiation from the ends, minimum broadside.
C. Omnidirectional.
D. Maximum radiation at 45 degrees to the plane of the antenna.
- The gain of an antenna, especially at VHF and above, is quoted in dBi. The “i” in
this expression stands for:
A. isotropic.
B. ideal.
C. ionosphere.
D. interpolated.
- What is one disadvantage of a random wire antenna?
A. It usually produces vertically polarized radiation.
B. It must be longer than 1 wavelength.
C. You may experience RF feedback in your station.
D. You must use an inverted T matching network for multi-band
operation.
- A “doublet antenna” is the most common in the amateur service. If you were to
cut this antenna for 3.75MHz, what would be the approximate length?
A. 38 meters (125 ft.).
B. 32 meters (105 ft.).
C. 45 meters (145 ft.).
D. 75 meters (245 ft.).
- What is the low angle radiation pattern of an ideal half-wavelength dipole
installed parallel to the earth?
A. It is a figure-eight, perpendicular to the antenna.
B. It is a circle (equal radiation in all directions).
C. It is two smaller lobes on one side of the antenna, and one larger lobe on
the other side.
D. It is a figure-eight, off both ends of the antenna.
- The impedance in ohms at the feed point of the dipole and folded dipole are,
respectively:
A. 73 and 150.
B. 73 and 300.
C. 52 and 100.
D. 52 and 200.
- How does the bandwidth of a folded dipole antenna compare with that of a simple
dipole?
A. It is essentially the same.
B. It is less than 50%.
C. It is 0.707 times the bandwidth.
D. It is greater.
- How do you calculate the length in meters (feet) of a
quarter-wavelength vertical antenna?
A. Divide 468 (1532) by the antenna's operating frequency (in MHz).
B. Divide 300 (982) by the antenna's operating frequency (in MHz).
C. Divide 71.5 (234) by the antenna's operating frequency (in MHz.).
D. Divide 150 (491) by the antenna's operating frequency (in
MHz)
- If you made a quarter-wavelength vertical antenna for 21.125 MHz,
how long would it be?
A. 3.6 meters (11.8 ft.).
B. 3.36 meters (11.0 ft.).
C. 7.2 meters (23.6 ft.).
D. 6.76 meters (22.2 ft.).
- If you made a half-wavelength vertical antenna for 223 MHz, how long
would it be?
A. 64 cm (25.2 in).
B. 128 cm (50.4 in).
C. 67.3 cm (26.5 in).
D. 134.6 cm (53 in).
- If a magnetic-base whip antenna is placed on the roof of a car, in
what direction does it send out radio energy?
A. Most of it aimed high in the sky.
B. Most of it goes equally in two opposite directions.
C. It goes out equally well in all horizontal directions.
D. Most of it goes in one direction.
- What is an advantage of downward sloping radials on a ground plane antenna?
A. It increases the radiation angle.
B. It brings the feed point impedance closer to 300 ohms.
C. It brings the feed point impedance closer to 50 ohms.
D. It lowers the radiation angle.
- What happens to the feed point impedance of a ground-plane antenna when the
radials are changed from horizontal to downward sloping?
A. It increases.
B. It decreases.
C. It stays the same.
D. It approaches zero.
- Which of the following transmission lines will give the best match to the base of a
quarter-wave ground-plane antenna?
A. 300 ohm balanced feed line.
B. 75 ohm balanced feed line.
C. 300 ohm coaxial cable.
D. 50 ohm coaxial cable.
- The main characteristic of a vertical antenna is that it will:
A. receive signals equally well from all compass points.
B. be very sensitive to signals coming from horizontal antennas.
C. require few insulators.
D. be easy to feed with TV ribbon feeder.
- What is the main reason so many VHF base and mobile antennas are 5/8 of a
wavelength?
A. The angle of radiation is high giving excellent local coverage.
B. The angle of radiation is low.
C. It is easy to match the antenna to the transmitter.
D. It's a convenient length on VHF.
- VHF signals from a mobile station using a vertical whip antenna will normally be
best received using a:
A. random length of wire.
B. horizontal ground-plane antenna.
C. vertical ground-plane antenna.
D. horizontal dipole antenna.
- What is a disadvantage of using an antenna equipped with traps?
A. It is too sharply directional at lower frequencies.
B. It will radiate harmonics.
C. It must be neutralized.
D. It can only be used on one band.
- What is the advantage of using a trap antenna?
A. It may be used for multi-band operation.
B. It has high directivity at the higher frequencies.
C. It has high gain.
D. It minimizes harmonic radiation.
- Why are loading coils often used with HF mobile vertical antennas?
A. To tune out capacitive reactance.
B. To lower the losses.
C. To lower the Q.
D. To improve reception.
- If an antenna is made longer, what happens to its resonance frequency?
A. It decreases.
B. It increases.
C. It stays the same.
D. It disappears.
- If an antenna is made shorter, what happens to its resonant frequency?
A. It stays the same.
B. It increases.
C. It disappears.
D. It decreases.
- Compared with a horizontal antenna, a vertical antenna will receive a vertically
polarized wave:
A. at weaker strength.
B. without any comparative difference.
C. if the antenna changes the polarization.
D. at greater strength.
- Adding a series inductance to an antenna would:
A. increase the resonant frequency.
B. Have little effect.
C. Decrease the resonant frequency.
D. Have no change on the resonant frequency.
- The resonant frequency of an antenna may be increased by:
A. lowering the radiating element.
B. increasing the height of the radiating element.
C. shortening the radiating element.
D. lengthening the radiating element.
- To lower the resonant frequency of an antenna, the operator should:
A. shorten it.
B. lengthen it.
C. ground one end.
D. center feed it with TV ribbon feeder.
- One solution to multiband operation with a shortened radiator is the
"trap dipole" or trap vertical. These traps are actually:
A. large wire-wound resistors.
B. A coil and capacitor in parallel.
C. Coils wrapped around a ferrite rod.
D. Hollow metal cans.
- Why is a 5/8 wavelength vertical antenna better than a ¼
wavelength vertical antenna for VHF or UHF mobile operations?
A. A 5/8 wavelength antenna has less corona loss.
B. A 5/8 wavelength antenna has more gain.
C. A 5/8 wavelength antenna is easier to install on a car.
D. A 5/8 wavelength antenna can handle more power.
- What is meant by antenna gain?
A. The numerical difference of the signal in the forward direction to the
signal in the back direction.
B. The numerical ratio of the power radiated by an antenna compared to the
transmitter output power.
C. The final amplifier gain minus the transmission line losses.
D. The numerical ratio relating the radiated signal strength of an antenna to
that of another antenna.
- What is a parasitic beam antenna?
A. An antenna where the driven element obtains its radio energy by induction
or radiation from director elements.
B. An antenna where all elements are driven by direct connection to the feed
line.
C. An antenna where some elements obtain the radio energy by induction or
radiation from a driven element.
D. An antenna where wave traps are used to magnetically couple the
elements.
- How can the bandwidth of a parasitic beam antenna be increased?
A. Use traps on the antenna.
B. Use larger diameter elements.
C. Use taper-diameter elements.
D. Use closer spacing.
- If a slightly shorter parasitic element is placed 0.1 wavelength
away from an HF dipole antenna, what effect will this have on the
antennas radiation pattern?
A. A major lobe will develop in the horizontal plane, parallel to the
two elements.
B. A major lobe will develop in the horizontal plane, toward the
parasitic element.
C. A major lobe will develop in the vertical plane, away from the
ground.
D. The radiation pattern will not be affected.
- If a slightly longer parasitic element is placed 0.1 wavelength away from an HF
dipole antenna, what effect will this have on the antenna's radiation
pattern?
A. A major lobe will develop in the horizontal plane, parallel to the
two elements.
B. A major lobe will develop in the vertical plane, away from the
ground.
C. A major lobe will develop in the horizontal plane, away from
the parasitic element, toward the dipole.
D. The radiation pattern will not be affected.
- The front-to-back ratio of a beam antenna is:
A. the forward power of the major lobe to the power in the backward
direction, both being measured at the 3dB points.
B. the ratio of the maximum forward power in the major lobe to the
maximum backward power radiation.
C. undefined.
D. the ratio of the forward power at the 3 dB points to the power radiated in
the backward direction.
- What electromagnetic polarization does a Yagi antenna have when its elements
are parallel to the earth's surface?
A. Helical.
B. Horizontal.
C. Vertical.
D. Circular.
- How many driven elements do most Yagi antennas have?
A. None.
B. Two.
C. Three.
D. One.
- Approximately how long is the driven element of a Yagi antenna for 14.0 MHz?
A. 5.21 meters (17 feet).
B. 10.67 meters (35 feet).
C. 20.12 meters (66 feet).
D. 10.21 meters (33 feet and 6 inches).
- Approximately how long is the driven element of a Yagi antenna for 21.1 MHz?
A. 5.18 meters (17 feet).
B. 6.4 meters (21 feet).
C. 3.2 meters (10.5 feet).
D. 12.8 meters (42 feet).
- Approximately how long is the reflector element of a Yagi antenna for 28.1 MHz?
A. 4.88 meters (16 feet).
B. 5.33 meters (17.5 feet).
C. 10.67 meters (35 feet).
D. 2.66 meters 8.75 feet).
- What is one effect of increasing the boom length and adding directors to a Yagi
antenna?
A. SWR increases.
B. Weight decreases.
C. Wind load decreases.
D. Gain increases.
- What are some advantages of a Yagi with wide element spacing?
A. High gain, less critical tuning and wider bandwidth.
B. High gain, lower loss and a low SWR.
C. High front-to-back ratio and lower input resistance.
D. Shorter boom length, lower weight and wind resistance.
- Why is a Yagi antenna often used for radiocommunications on the 20-meter
band?
A. It provides excellent Omnidirectional coverage in the horizontal plane.
B. It is smaller, less expensive and easier to erect than a dipole or a vertical
antenna.
C. It provides the highest possible angle of radiation for the HF bands.
D. It helps to reduce interference from other stations off to the side or behind.
- What does "front to back ratio"” mean in reference to a Yagi
antenna?
A. The relative position of the driven element with respect to the
reflectors and directors.
B. The power radiated in the major radiation lobe compared to the power
radiated in exactly the opposite direction.
C. The power radiated in the major radiation lobe compared to the power
radiated 90 degrees away from that direction.
D. The number of directors versus the number of reflectors.
- What is a good way to get maximum performance from a Yagi antenna?
A. Optimize the spacing and lengths of the elements.
B. Use RG-58 feed line.
C. Use a reactance bridge to measure the antenna performance from each
direction around the antenna.
D. Avoid using towers higher than 9 meters (30 feet) above the ground.
- The spacing between elements of a three-element Yagi antenna representing the
best overall choice is _______ of a wavelength.
A. 0.15.
B. 0.5.
C. 0.75.
D. 0.2.
- If the forward gain of a six-element Yagi is about 10 dB, what would the gain of
two of these antennas be if they were stacked?
A. 7 dB.
B. 13 dB.
C. 20 dB.
D. 10 dB.
- What is a cubical quad antenna?
A. A center-fed wire ½ electrical wavelength long.
B. A vertical conductor 1/4 electrical wavelength high, fed at the bottom.
C. Two or more parallel four-sided wire loops, each approximately one-
electrical wavelength long.
D. Four straight, parallel elements in line with each other, each approximately
½ electrical wavelength long.
- Approximately how long is each side of a cubical quad antenna driven
element for 21.4 MHz?
A. 3.54 meters (11.7 feet).
B. 0.36 meters (1.17 feet).
C. 14.33 meters (47 feet).
D. 143 meters (469 feet).
- The cubical quad or quad antenna consists of two or more square loops of
wire. The driven element has an approximate overall length of:
A. three-quarters of a wavelength.
B. one wavelength.
C. two wavelengths.
D. one-half wavelength.
- Approximately how long is each side of cubical quad antenna driven element for
14.3 MHz?
A. 21.43 meters (70.3 feet).
B. 5.36 meters (17.6 feet).
C. 53.34 meters (175 feet).
D. 7.14 meters (23.4 feet).
- Compared to a dipole antenna, what are the directional radiation characteristics of
a cubical quad antenna?
A. The quad has more directivity in both the horizontal and vertical planes.
B. The quad has more directivity in the horizontal plane but less directivity in
the vertical plane.
C. The quad has less directivity in the horizontal plane but more directivity in
the vertical plane.
D. The quad has less directivity in both the horizontal and vertical plane.
- Moving the feed point of a multi-element quad antenna from the side parallel to
ground to a side perpendicular to ground will have what effect?
A. It will change the antenna polarization from vertical to horizontal.
B. It will significantly decrease the antenna feed point impedance.
C. It will change the antenna polarization from horizontal to vertical.
D. It will significantly increase the antenna feed point impedance.
- The delta loop antenna consists of two or more triangular structures mounted on a
boom. The overall length of the driven element is approximately:
A. one-quarter wavelength.
B. one wavelength.
C. two wavelengths.
D. one-half wavelength.
- What does the term antenna front-to-back ratio mean in reference to a delta
loop antenna?
A. The relative position of the driven element with respect to the reflectors
and directors.
B. The power radiated in the major radiation lobe compared to the power
radiated in exactly the opposite direction.
C. The power radiated in the major radiation lobe compared to the power
radiated 90 degrees away from that direction.
D. The number of directors versus the number of reflectors.
- Which statement about two-element delta loops and quad antennas is true?
A. They perform very well only at HF.
B. They compare favorably with a three-element Yagi.
C. They are effective only when constructed using insulated wire.
D. They perform poorly above HF.
- What is a delta loop antenna?
A. A type of cubical quad antenna, except with triangular elements instead of
square.
B. A large copper ring or wire loop, used in direction finding.
C. An antenna system made of three vertical antennas, arranged in a
triangular shape.
D. An antenna made from several triangular coils of wire on an insulating
form.
- Approximately how long is each leg of a symmetrical delta loop antenna driven
element for 28.7 MHz?
A. 2.67 meters (8.75 feet).
B. 7.13 meters (23.4 feet).
C. 10.67 meters (35 feet).
D. 3.5 meters (11.5 feet).
- In a Yagi-Uda 3 element directional beam antenna, the __________ is primarily
for mechanical purposes.
A. reflector
B. driven element
C. director
D. boom
- In a Yagi-Uda 3 element directional beam antenna, the __________ is the longest
radiating element.
A. director
B. driven element
C. reflector
D. boom
- In a Yagi-Uda 3 element directional beam antenna, the __________ is the shortest
radiating element.
A. boom
B. reflector
C. director
D. driven element
- In a Yagi-Uda 3 element directional beam antenna, the __________ is not the
longest or shortest radiating element.
A. boom
B. director
C. driven element
D. reflector
The following questions are added to this quiz because decibels
are initially introduced when studying antennas. Although transmitters
have not been covered yet, you can think of a transmitter simply as a power
source.
- The unit "decibel" is used to indicate:
A. an oscilloscope waveform
B. a mathematical ratio
C. certain radio waves
D. a single sideband signal
- A two-times increase in power results in a change of how many
dB?
A. 6 dB higher.
B. 3 dB higher.
C. 12 dB higher.
D. 1 dB higher.
- How can you reduce your transmitter power by 3 dB?
A. Divide the original power by 1.5.
B. Divide the original power by 3.
C. Divide the original power by 4.
D. Divide the original power by 2.
- How can you increase your transmitters power by 6 dB?
A. Multiply the original power by 3.
B. Multiply the original power by 2.
C. Multiply the original power by 4.
D. Multiply the original power by 1.5.
- The power output of a transmitter is increased from 1 watt to 2 watts. This is a dB
increase of:
A. 30
B. 6
C. 3
D. 1
- The power of a transmitter is increased from 5 watts to 50 watts by a linear
amplifier. The power gain, expressed in dB, is:
A. 30 dB
B. 10 dB
C. 40 dB
D. 20 dB
- You add a 9 dB gain amplifier to your 2 watt handheld. What is the power output
of the combination?
A. 11 watts.
B. 16 watts.
C. 20 watts.
D. 18 watts.
- The power of a transmitter is increased from 2 watts to 8 watts. This is a power
gain of ________ dB.
A. 6 dB
B. 3 dB
C. 8 dB
D. 9 dB
- A local amateur reports your 100 W 2M simplex VHF transmission as 30 dB over
S9. To reduce your signal to S9, you would reduce your power to ________
watts.
A. 1 W
B. 10 W
C. 33.3 W
D. 100 mW
- If a signal strength report is 10 dB over S9, what should the report be if the
transmitter power is reduced from 1500 watts to 150 watts?
A. S9 plus 3 dB.
B. S9 minus 10 dB.
C. S9 plus 5 dB.
D. S9.
- If a field strength report is 20 dB over S9, what should the
report be if the transmitter power is reduced from 1500 watts to 150
watts?
A. S9 plus 10 dB.
B. S9 plus 5 dB.
C. S9 plus 3 dB.
D. S9.