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Amateur Extra Licensing Class

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Title: Amateur Extra Licensing Class


1
Amateur Extra Licensing Class
Feedlines Safety
  • Lake Area Radio Klub
  • Spring 2012

2
Amateur Radio Extra ClassElement 4 Course
Presentation
  • ELEMENT 4 Groupings
  • Rules Regs
  • Skywaves Contesting
  • Outer Space Comms
  • Visuals Video Modes
  • Digital Excitement with Computers Radios
  • Modulate Your Transmitters
  • Amps Power Supplies
  • Receivers with Great Filters

3
Amateur Radio Extra ClassElement 4 Course
Presentation
  • ELEMENT 4 Groupings
  • Oscillate Synthesize This!
  • Circuits Resonance for All!
  • Components in Your New Rig
  • Logically Speaking of Counters
  • Optos OpAmps Plus Solar
  • Test Gear, Testing, Testing 1,2,3
  • Antennas
  • Feedlines Safety

4
Amateur Radio Extra ClassFeedlines Safety
  • E9E01 The delta matching system matches 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 each side of element center.

5
Amateur Radio Extra ClassFeedlines Safety
  • E9E02 The gamma match is a system that matches
    an unbalanced feed line to an antenna by feeding
    the driven element both at the center of the
    element and at a fraction of a wavelength to one
    side of center.
  • E9E03 The stub match uses a section of
    transmission line shorted at the end and
    connected to the feed line near the antenna.

6
Amateur Radio Extra ClassFeedlines Safety
Impedance Matching Stubs
(1) Since a short at end makes the diagram look
like a long wire, this indicates the impedance is
an inductive reactance.
(2) Since an open at end makes the diagram look
like two parallel plates, this indicates the
impedance is a capacitive reactance.
7
Amateur Radio Extra ClassFeedlines Safety
Impedance Matching Stubs
(1) Since a short at the extreme end implies an
open a quarter-wave away, this makes the diagram
look like two parallel plates, which indicates
the impedance is a capacitive reactance.
(2) Since an open at the extreme end implies a
short a quarter-wave away, this makes the diagram
look like a long wire, which indicates the
impedance is a inductive reactance.
8
Amateur Radio Extra ClassFeedlines Safety
  • E9E04 The purpose of the series capacitor in a
    gamma-type antenna matching network is to
    compensate for the inductive reactance of the
    matching network.
  • E9E05 The driven element reactance must be
    capacitive in a 3-element Yagi to be tuned using
    a hairpin matching system.

9
Amateur Radio Extra ClassFeedlines Safety
  • E9E06 The equivalent lumped-constant network for
    a hairpin matching system on a 3-element Yagi is
    an L network.
  • E9E07 Reflection coefficient best describes the
    interactions at the load end of a mismatched
    transmission line.

The terms - VSWR, Return Loss, Reflected Power
are all ways to describe match or mismatch
between a transmitter and antenna system
With a VSWR of 1.4 to 1 only 2.8 of the
transmitter power is reflected back.
Impedance Mismatch Causes Reflected Wave
10
Amateur Radio Extra ClassFeedlines Safety
  • E9E08 An SWR greater than 11 measurement
    describes a mismatched transmission line.

SWR is the ratio of the maximum voltage
(resulting from the interaction of Incident and
reflected voltages along a transmission line) to
the minimum voltage.
SWR Bridges
11
Amateur Radio Extra ClassFeedlines Safety
  • E9E09 Using a Gamma match is an effective method
    of connecting a 50-ohm coaxial cable feed-line to
    a grounded tower so it can be used as a vertical
    antenna.
  • E9E10 Inserting a 1/4-wavelength piece of 75-ohm
    coaxial cable transmission line in series between
    the antenna terminals and the 50-ohm feed cable
    is an effective way to match an antenna with
    100-ohm terminal impedance to a 50-ohm coaxial
    cable feed-line.
  • E9E11 An effective way of matching a feed-line
    to a VHF or UHF antenna when the impedances of
    both the antenna and feed-line are unknown is to
    use the "universal stub" matching technique.

12
Amateur Radio Extra ClassFeedlines Safety
  • E9E12 The primary purpose of a "phasing line"
    when used with an antenna having multiple driven
    elements is to ensure that each driven element
    operates in concert with the others to create the
    desired antenna pattern.

Coaxial Cable
13
Amateur Radio Extra ClassFeedlines Safety
.Phasing line cont.
Dual Transmission Line
14
Amateur Radio Extra ClassFeedlines Safety
  • E9E13 The purpose of a "Wilkinson divider is to
    divide power equally among multiple loads while
    preventing changes in one load from disturbing
    power flow to the others.
  • E9F08 Velocity factor is the term for the ratio
    of the actual speed at which a signal travels
    through a transmission line to the speed of light
    in a vacuum.

15
Amateur Radio Extra ClassFeedlines Safety
  • E9F01 The velocity factor of a transmission line
    is the velocity of the wave in the transmission
    line divided by the velocity of light in a
    vacuum.
  • E9F02 The transmission line dielectric materials
    used determine the velocity factor in a
    transmission line.
  • E9F04 The typical velocity factor for a coaxial
    cable with solid polyethylene dielectric is 0.66.
  • E9F03 Because electrical signals move more
    slowly in a coaxial cable than in air, the
    physical length of a coaxial cable transmission
    line is shorter than its electrical length.

Velocity Factor Velocity of wave in
Transmission line / Velocity of light
16
Amateur Radio Extra ClassFeedlines Safety
  • E9F05The physical length of a coaxial
    transmission line that is electrically
    one-quarter wavelength long at 14.1 MHz is
    (Assuming a velocity factor of 0.66) 3.5 Meters.
  • E9F06 The physical length of a parallel
    conductor feed line that is electrically one-half
    wavelength long at 14.10 MHz (Assuming a velocity
    factor of 0.95) is 10 meters.

¼ Wavelength (in Transmission line)
(300/F(MHz)) / 4 x Velocity Factor
¼ Wavelength (in Transmission line) (300/14.1 x
.66) / 4
3.51 meters
14.04/4
½ Wavelength (in Transmission line)
(300/F(MHz))/2 x Velocity Factor
½ Wavelength (in Transmission line) (300/14.1 x
.95)/2
20.21/2
10.10 meters
17
Amateur Radio Extra ClassFeedlines Safety
  • E9F07 450-ohm ladder line, at 50 MHz, will have
    a lower loss when compared to 0.195-inch-diameter
    coaxial cable (such as RG-58).
  • E9F09 The physical length of a typical coaxial
    transmission line that is electrically
    one-quarter wavelength long at 7.2 MHz (Assume a
    velocity factor of 0.66) would be 6.9 meters.

¼ Wavelength in Transmission line)
(300/F(MHz))/4 x Velocity Factor
¼ Wavelength in Transmission line) (300/7.2
x..66)/4
27.50/4
6.87 meters
18
Amateur Radio Extra ClassFeedlines Safety
  • E9F10 A 1/8 wavelength transmission line
    presents an inductive reactance to a generator
    when the line is shorted at the far end.
  • E9F11 A 1/8 wavelength transmission line
    presents a capacitive reactance to a generator
    when the line is open at the far end.

Short Circuit at Antenna ZA 0
Impedance of coaxial stubs Impedance of coaxial stubs Impedance of coaxial stubs
Wavelength Open Stub Shorted Stub
1/8 Capacitive Inductive
1/4 Low Imp. High Imp.
1/2 High Imp. Low Imp.
Open Circuit at Antenna ZA 8
19
Amateur Radio Extra ClassFeedlines Safety
  • E9F12 A ¼ wavelength transmission line presents
    a very low impedance to a generator when the line
    is open at the far end.
  • E9F13 A ¼ wavelength transmission line presents
    a very high impedance to a generator when the
    line is shorted at the far end.

Open Circuit at Antenna ZA 8
Impedance of coaxial stubs Impedance of coaxial stubs Impedance of coaxial stubs
Wavelength Open Stub Shorted Stub
1/8 Capacitive Inductive
1/4 Low Imp. High Imp.
1/2 High Imp. Low Imp.
Short Circuit at Antenna ZA 0
20
Amateur Radio Extra ClassFeedlines Safety
  • E9F14 A ½ wavelength transmission line presents
    a very low impedance to a generator when the line
    is shorted at the far end.
  • E9F15 A ½ wavelength transmission line presents
    very high impedance to a generator when the line
    is open at the far end.

Short Circuit at Antenna ZA 0
Impedance of coaxial stubs Impedance of coaxial stubs Impedance of coaxial stubs
Wavelength Open Stub Shorted Stub
1/8 Capacitive Inductive
1/4 Low Imp. High Imp.
1/2 High Imp. Low Imp.
Open Circuit at Antenna ZA 8
21
Amateur Radio Extra ClassFeedlines Safety
  • E9F16 The primary differences between
    foam-dielectric coaxial cable as opposed to
    solid-dielectric cable, assuming all other
    parameters are the same are reduced safe
    operating voltage limits, reduced losses per unit
    of length and higher velocity factor.

Coax Cable Type, Size and Loss per 100 Feet Coax Cable Type, Size and Loss per 100 Feet Coax Cable Type, Size and Loss per 100 Feet Coax Cable Type, Size and Loss per 100 Feet
Coax Type Size Loss/100MHz Loss/400MHz
RG-6 Large 2.3 dB 4.7 dB
RG-59 Medium 2.9 dB 5.9 dB
RG-58U Small 4.3 dB 9.4 dB
RG-8X Medium 3.7 dB 8.0 dB
RG-8U Large 1.9 dB 4.1 dB
RG-213 Large 1.9 dB 4.5 dB
Hardliner Large, Rigid 0.5 dB 1.5 dB
22
Amateur Radio Extra ClassFeedlines Safety
  • E4A07 The advantage of using an antenna analyzer
    vs. a SWR bridge to measure antenna SWR is that
    antenna analyzers typically do not need an
    external RF source.
  • E4B12 When using a portable SWR analyzer to
    measure antenna resonance and feed-point
    impedance, connect the antenna feed line directly
    to the analyzer's test connector.

23
Amateur Radio Extra ClassFeedlines Safety
  • E9G01 Impedance along transmission lines can be
    calculated using a Smith chart.

Finding Antenna Impedance, ZA, when Fed with
Known Length of Transmission Line ( in
Wavelengths) of Given Impedance, ZO.
Smith Chart
24
Amateur Radio Extra ClassFeedlines Safety
  • E4A08 An antenna analyzer would be best for
    measuring the SWR of a beam antenna.

AntennaSmithautomatic antenna impedance analyzer
25
Amateur Radio Extra ClassFeedlines Safety
  • E9G02 The coordinate system is used in a Smith
    chart is resistance circles and reactance arcs.

Circles
Arcs
26
Amateur Radio Extra ClassFeedlines Safety
  • E9G03 Impedance and SWR values in transmission
    lines are often determined using a Smith chart.
  • E9G04 Resistance and reactance are the two
    families of circles and arcs that make up a Smith
    chart.
  • E9G05 The type of chart shown in Figure E9-3 is
    a Smith chart.

Figure E9-3
27
Amateur Radio Extra ClassFeedlines Safety
  • E9G06 On the Smith chart shown in Figure E9-3,
    the name of the large outer circle on which the
    reactance arcs terminate is the reactance axis.
  • E9G07 On the Smith chart shown in Figure E9-3,
    the only straight line shown is the resistance
    axis.

Smith Charts save hours of work.
Figure E9-3
28
Amateur Radio Extra ClassFeedlines Safety
  • E9G08 The process of normalization with regard
    to a Smith chart is reassigning impedance values
    with regard to the prime center.
  • E9G09 Standing-wave ratio circles are a third
    family of circles that are often added to a Smith
    chart during the process of solving problems.
  • E9F10 The arcs on a Smith chart represent points
    with constant reactance.
  • E9G11 The wavelength scales on a Smith chart are
    calibrated in fractions of transmission line
    electrical wavelength.

29
Amateur Radio Extra ClassFeedlines Safety
  • E9C04 A basic rhombic antenna is a
    bidirectional. It is four-sided. Each side is
    one or more wavelengths long and is open at the
    end opposite the transmission line connection.
  • E9C05 The main advantages of a terminated
    rhombic antenna are wide frequency range, high
    gain and high front-to-back ratio (gain).

Open ended
Terminated
30
Amateur Radio Extra ClassFeedlines Safety
  • E9C06 The disadvantages of a terminated rhombic
    antenna for the HF bands are that the antenna
    requires a large physical area and 4 separate
    supports.
  • E9C07 A terminating resistor on a rhombic
    antenna changes the radiation pattern from
    bidirectional to unidirectional.

unidirectional
bidirectional
31
Amateur Radio Extra ClassFeedlines Safety
  • E9H04 Effective radiated power is the term that
    describes station output (including the
    transmitter, antenna and everything in between),
    when considering transmitter power and system
    gains and losses.
  • E9H01 The effective radiated power of a repeater
    station with 150 watts transmitter power output,
    2-dB feed line loss, 2.2-dB duplexer loss and
    7-dBd antenna gain is 286 watts.
  • E9H02 The effective radiated power of a repeater
    station with 200 watts transmitter power output,
    4-dB feed line loss, 3.2-dB duplexer loss, 0.8-dB
    circulator loss and 10-dBd antenna gain is 317
    watts.

ERP Power gain(s) Loss(es)
ERP 150 watts (7 dB) (2 dB 2.2 dB)
150 watts 2.8 dB
Gain/loss ratio 10(dB/10)or 10(2.8/10) or
10.28 or 1.905
ERP 150 watts x 1.905 (the overall db gain/loss
ratio)
285.8 watts
ERP Power gain(s) Loss(es)
ERP 200 watts (10 dB) (4 dB 3.2 dB 0.8
dB)
200 watts 2 dB
Gain/loss ratio 10(dB/10)or 10(2.0/10) or
10.20 or 1.584
ERP 200 watts x 1.584 (the overall db gain/loss
ratio)
316.9 watts
32
Amateur Radio Extra ClassFeedlines Safety
  • E9H03 The effective radiated power of a repeater
    station with 200 watts transmitter power output,
    2-dB feed line loss, 2.8-dB duplexer loss, 1.2-dB
    circulator loss and 7-dBd antenna gain is 252
    watts.
  • E9H04 Effective radiated power is the term that
    describes station output (including the
    transmitter, antenna and everything in between),
    when considering transmitter power and system
    gains and losses.
  • E9D01 The gain of a parabolic dish antenna
    increases 6 dB when the operating frequency is
    doubled.

ERP Power gain(s) Loss(es)
ERP 200 watts (7 dB) (2 dB 2.8 dB 1.2 dB)
ERP 200 watts 1 dB
Gain/loss ratio 10(dB/10) or 10(1/10) or
10.1 or 1.258
ERP 200 watts x 1.258 (the overall db
gain/loss ratio)
251.7 watts
33
Amateur Radio Extra ClassFeedlines Safety
  • E9D03 The beamwidth of an antenna decreases as
    the gain is increased.
  • E9D04 It desirable for a ground-mounted
    satellite communications antenna system to be
    able to move in both azimuth and elevation in
    order to track the satellite as it orbits the
    earth.
  • E0A11 Injuries from radiation (RF) leaks that
    exceed the MPE limits are considered a
    significant hazard when operating a klystron or
    cavity magnetron transmitter.
  • E0A10 PCBs (Polychlorinated biphenyls) are
    found in some electronic components, such as
    high-voltage capacitors and transformers, are
    considered toxic.
  • E0A05 One of the potential hazards of using
    microwaves in the amateur radio bands is the high
    gain antennas commonly used can result in high
    exposure levels.

The antenna becomes more directional
34
Amateur Radio Extra ClassFeedlines Safety
  • E0A03 A practical way to estimate whether the RF
    fields produced by an amateur radio station are
    within permissible MPE limits would be to use a
    computer-based antenna modeling program to
    calculate field strength at accessible locations.
  • E0A08 SAR (Specific Absorption Rate) is a
    measure of the rate at which RF energy is
    absorbed by the body.
  • E0A02 When evaluating exposure levels from your
    station at a neighbors home, you must make sure
    signals from your station are less than the
    uncontrolled MPE limits.
  • E0A06 There are separate electric (E) and
    magnetic (H) field MPE limits because

Ground reflections and scattering make the field
impedance vary with location.
E field and H field radiation intensity peaks
can occur at different locations.
35
Amateur Radio Extra ClassFeedlines Safety
  • E9C13 When constructing a Beverage antenna, to
    achieve good performance at the desired frequency
    it should be one or more wavelengths long.
  • E9H09 A receiving loop antenna is an antenna
    made of one or more turns of wire wound in the
    shape of a large open coil.
  • E9H10 The output voltage of a receiving loop
    antenna can be increased by increasing either the
    number of wire turns in the loop or the area of
    the loop structure.

36
Amateur Radio Extra ClassFeedlines Safety
  • E9H11 A cardioid pattern is desirable for a
    direction-finding system because response
    characteristics of the cardioid pattern can
    assist in determining the direction of the
    desired station.
  • E9H12 An advantage of using a shielded loop
    antenna for direction finding is that it is
    electro-statically balanced against ground,
    giving better nulls.

Two ¼ wave vertical antennas fed 90-degrees out
of phase will produce a cardioid radiation
pattern. Deep null will be 180 degrees from
signal being received.
37
Amateur Radio Extra ClassFeedlines Safety
  • E9H05 The main drawback of a wire-loop antenna
    for direction finding is that it has a
    bidirectional pattern.
  • E9H07 An RF attenuator is desirable in a
    receiver used for direction finding because it
    prevents receiver overload from extremely strong
    signals.

38
Amateur Radio Extra ClassFeedlines Safety
  • E9H08 The function of a sense antenna is that it
    modifies the pattern of a DF antenna array to
    provide a null in one direction.
  • E9H06 The triangulation method of direction
    finding is when antenna headings from several
    different receiving stations are used to locate
    the signal source.

Ferrite-core bar antenna and vertical rod sense
antenna.
39
Element 4 Extra Class Question Pool
Feedlines and Safety
Valid July 1, 2008 Through June 30, 2012
40
E9E01 What system matches 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 each
side of element center?
  • The gamma matching system
  • The delta matching system
  • The omega matching system
  • The stub matching system

41
E9E02 What is the name of an antenna matching
system that matches an unbalanced feed line to an
antenna by feeding the driven element both at the
center of the element and at a fraction of a
wavelength to one side of center?
  1. The gamma match
  2. The delta match
  3. The omega match
  4. The stub match

42
E9E03 What is the name of the matching system
that uses a short perpendicular section of
transmission line connected to the feed line near
the antenna?
  • A. The gamma match
  • B. The delta match
  • C. The omega match
  • D. The stub match

43
E9E04 What is the purpose of the series
capacitor in a gamma-type antenna matching
network?
  1. To provide DC isolation between the feed-line and
    the antenna
  2. To compensate for the inductive reactance of the
    matching network
  3. To provide a rejection notch to prevent the
    radiation of harmonics
  4. To transform the antenna impedance to a higher
    value

44
E9E05 How must the driven element in a 3-element
Yagi be tuned to use a hairpin matching system?
  1. The driven element reactance must be capacitive
  2. The driven element reactance must be inductive
  3. The driven element resonance must be lower than
    the operating frequency
  4. The driven element radiation resistance must be
    higher than the characteristic impedance of the
    transmission line

45
E9E06 What is the equivalent lumped-constant
network for a hairpin matching system on a
3-element Yagi?
  1. Pi network
  2. Pi-L network
  3. L network
  4. Parallel-resonant tank

46
E9E07 What parameter best describes the
interactions at the load end of a mismatched
transmission line?
  1. Characteristic impedance
  2. Reflection coefficient
  3. Velocity factor
  4. Dielectric Constant

47
E9E08 Which of the following measurements
describes a mismatched transmission line?
  1. An SWR less than 11
  2. A reflection coefficient greater than 1
  3. A dielectric constant greater than 1
  4. An SWR greater than 11

48
E9E09 Which of these matching systems is an
effective method of connecting a 50-ohm coaxial
cable feed-line to a grounded tower so it can be
used as a vertical antenna?
  1. Double-bazooka match
  2. Hairpin match
  3. Gamma match
  4. All of these answers are correct

49
E9E10 Which of these choices is an effective way
to match an antenna with a 100-ohm terminal
impedance to a 50-ohm coaxial cable feed-line?
  1. Connect a 1/4-wavelength open stub of 300-ohm
    twin-lead in parallel with the coaxial feed-line
    where it connects to the antenna
  2. Insert a 1/2 wavelength piece of 300-ohm
    twin-lead in series between the antenna terminals
    and the 50-ohm feed cable
  3. Insert a 1/4-wavelength piece of 75-ohm coaxial
    cable transmission line in series between the
    antenna terminals and the 50-ohm feed cable
  4. Connect 1/2 wavelength shorted stub of 75-ohm
    cable in parallel with the 50-ohm cable where it
    attaches to the antenna

50
E9E11 What is an effective way of matching a
feed-line to a VHF or UHF antenna when the
impedances of both the antenna and feed-line are
unknown?
  1. Use a 50-ohm 11 balun between the antenna and
    feed-line
  2. Use the "universal stub" matching technique
  3. Connect a series-resonant LC network across the
    antenna feed terminals
  4. Connect a parallel-resonant LC network across the
    antenna feed terminals

51
E9E12 What is the primary purpose of a "phasing
line" when used with an antenna having multiple
driven elements?
  1. It ensures that each driven element operates in
    concert with the others to create the desired
    antenna pattern
  2. It prevents reflected power from traveling back
    down the feed-line and causing harmonic radiation
    from the transmitter
  3. It allows single-band antennas to operate on
    other bands
  4. It makes sure the antenna has a low-angle
    radiation pattern

52
E9E13 What is the purpose of a "Wilkinson
divider"?
  1. It divides the operating frequency of a
    transmitter signal so it can be used on a lower
    frequency band
  2. It is used to feed high-impedance antennas from a
    low-impedance source
  3. It divides power equally among multiple loads
    while preventing changes in one load from
    disturbing power flow to the others
  4. It is used to feed low-impedance loads from a
    high-impedance source

53
E9F08 What is the term for the ratio of the
actual speed at which a signal travels through a
transmission line to the speed of light in a
vacuum?
  1. Velocity factor
  2. Characteristic impedance
  3. Surge impedance
  4. Standing wave ratio

54
E9F01 What is the 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 in the transmission line
    multiplied by the velocity of light in a vacuum
  4. The velocity of the wave in the transmission line
    divided by the velocity of light in a vacuum

55
E9F02 What determines the velocity factor in a
transmission line?
  1. The termination impedance
  2. The line length
  3. Dielectric materials used in the line
  4. The center conductor resistivity

56
E9F04 What is the typical velocity factor for a
coaxial cable with solid polyethylene dielectric?
  1. 2.70
  2. 0.66
  3. 0.30
  4. 0.10

57
E9F03 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. The characteristic impedance is higher in a
    parallel feed line
  3. The surge impedance is higher in a parallel feed
    line
  4. Electrical signals move more slowly in a coaxial
    cable than in air

58
E9F05 What is the physical length of a coaxial
transmission line that is electrically
one-quarter wavelength long at 14.1 MHz? (Assume
a velocity factor of 0.66.)
  1. 20 meters
  2. 2.3 meters
  3. 3.5 meters
  4. 0.2 meters

59
E9F06 What is the physical length of a parallel
conductor feed line that is electrically one-half
wavelength long at 14.10 MHz? (Assume a velocity
factor of 0.95.)
  1. 15 meters
  2. 20 meters
  3. 10 meters
  4. 71 meters

60
E9F07 What characteristic will 450-ohm ladder
line have at 50 MHz, as compared to
0.195-inch-diameter coaxial cable (such as RG-58)?
  1. Lower loss
  2. Higher SWR
  3. Smaller reflection coefficient
  4. Lower velocity factor

61
E9F09 What would be the physical length of a
typical coaxial transmission line that is
electrically one-quarter wavelength long at 7.2
MHz? (Assume a velocity factor of 0.66)
  1. 10 meters
  2. 6.9 meters
  3. 24 meters
  4. 50 meters

62
E9F10 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

63
E9F11 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

64
E9F12 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

65
E9F13 What kind of impedance does a
1/4-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
    transmission line
  4. The same as the generator output impedance

66
E9F14 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

67
E9F15 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

68
E9F16 What is the primary difference between
foam-dielectric coaxial cable as opposed to
solid-dielectric cable, assuming all other
parameters are the same?
  1. Reduced safe operating voltage limits
  2. Reduced losses per unit of length
  3. Higher velocity factor
  4. All of these answers are correct

69
E4A07 Which of the following is an advantage
of using an antenna analyzer vs. a SWR bridge to
measure antenna SWR?
  1. Antenna analyzers automatically tune your antenna
    for resonance
  2. Antenna analyzers typically do not need an
    external RF source
  3. Antenna analyzers typically display a
    time-varying representation of the modulation
    envelope
  4. All of these answers are correct

70
E4B12 How should a portable SWR analyzer be
connected when measuring antenna resonance and
feedpoint impedance?
  1. Loosely couple the analyzer near the antenna base
  2. Connect the analyzer via a high-impedance
    transformer to the antenna
  3. Connect the antenna and a dummy load to the
    analyzer
  4. Connect the antenna feed line directly to the
    analyzer's connector

71
E9G01 Which of the following can be calculated
using a Smith chart?
  1. Impedance along transmission lines
  2. Radiation resistance
  3. Antenna radiation pattern
  4. Radio propagation

72
E4A08 Which of the following instruments would
be best for measuring the SWR of a beam antenna?
  1. A spectrum analyzer
  2. A Q meter
  3. An ohmmeter
  4. An antenna analyzer

73
E9G02 What type of coordinate system is used in
a Smith chart?
  1. Voltage circles and current arcs
  2. Resistance circles and reactance arcs
  3. Voltage lines and current chords
  4. Resistance lines and reactance chords

74
E9G03 Which of the following is often
determined using a Smith chart?
  1. Beam headings and radiation patterns
  2. Satellite azimuth and elevation bearings
  3. Impedance and SWR values in transmission lines
  4. Trigonometric functions

75
E9G04 What are the two families of circles and
arcs that make up a Smith chart?
  1. Resistance and voltage
  2. Reactance and voltage
  3. Resistance and reactance
  4. Voltage and impedance

76
E9G05 What type of chart is shown in Figure
E9-3?
  1. Smith chart
  2. Free-space radiation directivity chart
  3. Elevation angle radiation pattern chart
  4. Azimuth angle radiation pattern chart

77
E9G06 On the Smith chart shown in Figure E9-3,
what is the name for the large outer circle on
which the reactance arcs terminate?
  1. Prime axis
  2. Reactance axis
  3. Impedance axis
  4. Polar axis

78
E9G07 On the Smith chart shown in Figure E9-3,
what is the only straight line shown?
  1. The reactance axis
  2. The current axis
  3. The voltage axis
  4. The resistance axis

79
E9G08 What is the process of normalization with
regard to a Smith chart?
  1. Reassigning resistance values with regard to the
    reactance axis
  2. Reassigning reactance values with regard to the
    resistance axis
  3. Reassigning impedance values with regard to the
    prime center
  4. Reassigning prime center with regard to the
    reactance axis

80
E9G09 What third family of circles is often
added to a Smith chart during the process of
solving problems?
  1. Standing-wave ratio circles
  2. Antenna-length circles
  3. Coaxial-length circles
  4. Radiation-pattern circles

81
E9G10 What do the arcs on a Smith chart
represent?
  1. Frequency
  2. SWR
  3. Points with constant resistance
  4. Points with constant reactance

82
E9G11 How are the wavelength scales on a Smith
chart calibrated?
  1. In fractions of transmission line electrical
    frequency
  2. In fractions of transmission line electrical
    wavelength
  3. In fractions of antenna electrical wavelength
  4. In fractions of antenna electrical frequency

83
E9C04 Which of the following describes a basic
rhombic antenna?
  1. Unidirectional four-sided, each side one
    quarter-wavelength long terminated in a
    resistance equal to its characteristic impedance
  2. Bidirectional four-sided, each side one or more
    wavelengths long open at the end opposite the
    transmission line connection
  3. Four-sided an LC network at each corner except
    for the transmission connection
  4. Four-sided, each side of a different physical
    length

84
E9C05 What are the main advantages of a
terminated rhombic antenna?
  1. Wide frequency range, high gain and high
    front-to-back ratio
  2. High front-to-back ratio, compact size and high
    gain
  3. Unidirectional radiation pattern, high gain and
    compact size
  4. Bidirectional radiation pattern, high gain and
    wide frequency range

85
E9C06 What are the disadvantages of a terminated
rhombic antenna for the HF bands?
  1. The antenna has a very narrow operating bandwidth
  2. The antenna produces a circularly polarized
    signal
  3. The antenna requires a large physical area and 4
    separate supports
  4. The antenna is more sensitive to man-made static
    than any other type

86
E9C07 What is the effect of a terminating
resistor on a rhombic antenna?
  1. It reflects the standing waves on the antenna
    elements back to the transmitter
  2. It changes the radiation pattern from
    bidirectional to unidirectional
  3. It changes the radiation pattern from horizontal
    to vertical polarization
  4. It decreases the ground loss

87
E9H04 What term describes station output
(including the transmitter, antenna and
everything in between), when considering
transmitter power and system gains and losses?
  1. Power factor
  2. Half-power bandwidth
  3. Effective radiated power
  4. Apparent power

88
E9H01 What is the effective radiated power of a
repeater station with 150 watts transmitter power
output, 2-dB feed line loss, 2.2-dB duplexer loss
and 7-dBd antenna gain?
  1. 1977 watts
  2. 78.7 watts
  3. 420 watts
  4. 286 watts

89
E9H02 What is the effective radiated power of a
repeater station with 200 watts transmitter power
output, 4-dB feed line loss, 3.2-dB duplexer
loss, 0.8-dB circulator loss and 10-dBd antenna
gain?
  1. 317 watts
  2. 2000 watts
  3. 126 watts
  4. 300 watts

90
E9H03 What is the effective radiated power of a
repeater station with 200 watts transmitter power
output, 2-dB feed line loss, 2.8-dB duplexer
loss, 1.2-dB circulator loss and 7-dBd antenna
gain?
  1. 159 watts
  2. 252 watts
  3. 632 watts
  4. 63.2 watts

91
E0A04 When evaluating a site with multiple
transmitters operating at the same time, the
operators and licensees of which transmitters are
responsible for mitigating over-exposure
situations?
  1. Only the most powerful transmitter
  2. Only commercial transmitters
  3. Each transmitter that produces 5 or more of its
    maximum permissible exposure limit at accessible
    locations
  4. Each transmitter operating with a duty-cycle
    greater than 50

92
E9D01 How does the gain of a parabolic dish
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

93
E9D03 How does the beamwidth of an antenna vary
as the gain is increased?
  1. It increases geometrically
  2. It increases arithmetically
  3. It is essentially unaffected
  4. It decreases

94
E9D04 Why is it desirable for a ground-mounted
satellite communications antenna system to be
able to move in both azimuth and elevation?
  1. In order to track the satellite as it orbits the
    earth
  2. So the antenna can be pointed away from
    interfering signals
  3. So the antenna can be positioned to cancel the
    effects of Faraday rotation
  4. To rotate antenna polarization to match that of
    the satellite

95
E0A11 Which of these items might be a significant
hazard when operating a klystron or cavity
magnetron transmitter?
  1. Hearing loss caused by high voltage corona
    discharge
  2. Blood clotting from the intense magnetic field
  3. Injury from radiation leaks that exceed the MPE
    limits
  4. Ingestion of ozone gas from the cooling system

96
E0A10 What material found in some electronic
components such as high-voltage capacitors and
transformers is considered toxic?
  1. Polychlorinated biphenyls
  2. Polyethylene
  3. Polytetrafluroethylene
  4. Polymorphic silicon

97
E0A05 What is one of the potential hazards of
using microwaves in the amateur radio bands?
  1. Microwaves are ionizing radiation
  2. The high gain antennas commonly used can result
    in high exposure levels
  3. Microwaves often travel long distances by
    ionospheric reflection
  4. The extremely high frequency energy can damage
    the joints of antenna structures

98
E0A03 Which of the following would be a practical
way to estimate whether the RF fields produced by
an amateur radio station are within permissible
MPE limits?
  1. Use a calibrated antenna analyzer
  2. Use a hand calculator plus Smith-chart equations
    to calculate the fields
  3. Walk around under the antennas with a neon-lamp
    probe to find the strongest fields
  4. Use a computer-based antenna modeling program to
    calculate field strength at accessible locations

99
E0A08 What does SAR measure?
  1. Synthetic Aperture Ratio of the human body
  2. Signal Amplification Rating
  3. The rate at which RF energy is absorbed by the
    body
  4. The rate of RF energy reflected from stationary
    terrain

100
E0A02 When evaluating exposure levels from your
station at a neighbors home, what must you do?
  1. Make sure signals from your station are less than
    the controlled MPE limits
  2. Make sure signals from your station are less than
    the uncontrolled MPE limits
  3. Nothing you need only evaluate exposure levels
    on your own property
  4. Advise your neighbors of the results of your tests

101
E0A06 Why are there separate electric (E) and
magnetic (H) field MPE limits?
  1. The body reacts to electromagnetic radiation from
    both the E and H fields
  2. Ground reflections and scattering make the field
    impedance vary with location
  3. E field and H field radiation intensity peaks can
    occur at different locations
  4. All of these answers are correct

102
E9C13 When constructing a Beverage antenna, which
of the following factors should be included in
the design to achieve good performance at the
desired frequency?
  1. Its overall length must not exceed 1/4 wavelength
  2. It must be mounted more than 1 wavelength above
    ground
  3. It should be configured as a four-sided loop
  4. It should be one or more wavelengths long

103
E9H09 What is a receiving loop antenna?
  1. A large circularly-polarized antenna
  2. A small coil of wire tightly wound around a
    toroidal ferrite core
  3. One or more turns of wire wound in the shape of a
    large open coil
  4. Any antenna coupled to a feed line through an
    inductive loop of wire

104
E9H10 How can the output voltage of a receiving
loop antenna be increased?
  1. By reducing the permeability of the loop shield
  2. By increasing the number of wire turns in the
    loop and reducing the area of the loop structure
  3. By reducing either the number of wire turns in
    the loop or the area of the loop structure
  4. By increasing either the number of wire turns in
    the loop or the area of the loop structure

105
E9H11 Why is an antenna with a cardioid pattern
desirable for a direction-finding system?
  1. The broad-side responses of the cardioid pattern
    can be aimed at the desired station
  2. The response characteristics of the cardioid
    pattern can assist in determining the direction
    of the desired station
  3. The extra side lobes in the cardioid pattern can
    pinpoint the direction of the desired station
  4. The high-radiation angle of the cardioid pattern
    is useful for short-distance direction finding

106
E9H12 What is an advantage of using a shielded
loop antenna for direction finding?
  1. It automatically cancels ignition noise pickup in
    mobile installations
  2. It is electro-statically balanced against ground,
    giving better nulls
  3. It eliminates tracking errors caused by strong
    out-of-band signals
  4. It allows stations to communicate without giving
    away their position

107
E9H05 What is the main drawback of a wire-loop
antenna for direction finding?
  1. It has a bidirectional pattern
  2. It is non-rotatable
  3. It receives equally well in all directions
  4. It is practical for use only on VHF bands

108
E9H07 Why is an RF attenuator desirable in a
receiver used for direction finding?
  1. It narrows the bandwidth of the received signal
  2. It eliminates the effects of isotropic radiation
  3. It reduces loss of received signals caused by
    antenna pattern nulls
  4. It prevents receiver overload from extremely
    strong signals

109
E9H08 What is the function of a sense antenna?
  1. It modifies the pattern of a DF antenna array to
    provide a null in one direction
  2. It increases the sensitivity of a DF antenna
    array
  3. It allows DF antennas to receive signals at
    different vertical angles
  4. It provides diversity reception that cancels
    multipath signals

110
E9H06 What is the triangulation method of
direction finding?
  1. The geometric angle of sky waves from the source
    are used to determine its position
  2. A fixed receiving station plots three headings
    from the signal source on a map
  3. Antenna headings from several different receiving
    stations are used to locate the signal source
  4. A fixed receiving station uses three different
    antennas to plot the location of the signal source
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