Amateur Extra Licensing Class

Feedlines Safety

- Lake Area Radio Klub
- Spring 2012

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

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

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.

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.

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.

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.

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.

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

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

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.

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

Amateur Radio Extra ClassFeedlines Safety

.Phasing line cont.

Dual Transmission Line

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.

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

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

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

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

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

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

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

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.

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

Amateur Radio Extra ClassFeedlines Safety

- E4A08 An antenna analyzer would be best for

measuring the SWR of a beam antenna.

AntennaSmithautomatic antenna impedance analyzer

Amateur Radio Extra ClassFeedlines Safety

- E9G02 The coordinate system is used in a Smith

chart is resistance circles and reactance arcs.

Circles

Arcs

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

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

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.

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

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

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

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

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

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.

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.

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.

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.

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.

Element 4 Extra Class Question Pool

Feedlines and Safety

Valid July 1, 2008 Through June 30, 2012

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

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?

- The gamma match
- The delta match
- The omega match
- The stub match

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

E9E04 What is the purpose of the series

capacitor in a gamma-type antenna matching

network?

- To provide DC isolation between the feed-line and

the antenna - To compensate for the inductive reactance of the

matching network - To provide a rejection notch to prevent the

radiation of harmonics - To transform the antenna impedance to a higher

value

E9E05 How must the driven element in a 3-element

Yagi be tuned to use a hairpin matching system?

- The driven element reactance must be capacitive
- The driven element reactance must be inductive
- The driven element resonance must be lower than

the operating frequency - The driven element radiation resistance must be

higher than the characteristic impedance of the

transmission line

E9E06 What is the equivalent lumped-constant

network for a hairpin matching system on a

3-element Yagi?

- Pi network
- Pi-L network
- L network
- Parallel-resonant tank

E9E07 What parameter best describes the

interactions at the load end of a mismatched

transmission line?

- Characteristic impedance
- Reflection coefficient
- Velocity factor
- Dielectric Constant

E9E08 Which of the following measurements

describes a mismatched transmission line?

- An SWR less than 11
- A reflection coefficient greater than 1
- A dielectric constant greater than 1
- An SWR greater than 11

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?

- Double-bazooka match
- Hairpin match
- Gamma match
- All of these answers are correct

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?

- 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 - Insert a 1/2 wavelength piece of 300-ohm

twin-lead in series between the antenna terminals

and the 50-ohm feed cable - 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 - Connect 1/2 wavelength shorted stub of 75-ohm

cable in parallel with the 50-ohm cable where it

attaches to the antenna

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?

- Use a 50-ohm 11 balun between the antenna and

feed-line - Use the "universal stub" matching technique
- Connect a series-resonant LC network across the

antenna feed terminals - Connect a parallel-resonant LC network across the

antenna feed terminals

E9E12 What is the primary purpose of a "phasing

line" when used with an antenna having multiple

driven elements?

- It ensures that each driven element operates in

concert with the others to create the desired

antenna pattern - It prevents reflected power from traveling back

down the feed-line and causing harmonic radiation

from the transmitter - It allows single-band antennas to operate on

other bands - It makes sure the antenna has a low-angle

radiation pattern

E9E13 What is the purpose of a "Wilkinson

divider"?

- It divides the operating frequency of a

transmitter signal so it can be used on a lower

frequency band - It is used to feed high-impedance antennas from a

low-impedance source - It divides power equally among multiple loads

while preventing changes in one load from

disturbing power flow to the others - It is used to feed low-impedance loads from a

high-impedance source

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?

- Velocity factor
- Characteristic impedance
- Surge impedance
- Standing wave ratio

E9F01 What is the velocity factor of a

transmission line?

- The ratio of the characteristic impedance of the

line to the terminating impedance - The index of shielding for coaxial cable
- The velocity of the wave in the transmission line

multiplied by the velocity of light in a vacuum - The velocity of the wave in the transmission line

divided by the velocity of light in a vacuum

E9F02 What determines the velocity factor in a

transmission line?

- The termination impedance
- The line length
- Dielectric materials used in the line
- The center conductor resistivity

E9F04 What is the typical velocity factor for a

coaxial cable with solid polyethylene dielectric?

- 2.70
- 0.66
- 0.30
- 0.10

E9F03 Why is the physical length of a coaxial

cable transmission line shorter than its

electrical length?

- Skin effect is less pronounced in the coaxial

cable - The characteristic impedance is higher in a

parallel feed line - The surge impedance is higher in a parallel feed

line - Electrical signals move more slowly in a coaxial

cable than in air

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.)

- 20 meters
- 2.3 meters
- 3.5 meters
- 0.2 meters

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.)

- 15 meters
- 20 meters
- 10 meters
- 71 meters

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)?

- Lower loss
- Higher SWR
- Smaller reflection coefficient
- Lower velocity factor

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)

- 10 meters
- 6.9 meters
- 24 meters
- 50 meters

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?

- A capacitive reactance
- The same as the characteristic impedance of the

line - An inductive reactance
- The same as the input impedance to the final

generator stage

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?

- The same as the characteristic impedance of the

line - An inductive reactance
- A capacitive reactance
- The same as the input impedance of the final

generator stage

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?

- A very high impedance
- A very low impedance
- The same as the characteristic impedance of the

line - The same as the input impedance to the final

generator stage

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?

- A very high impedance
- A very low impedance
- The same as the characteristic impedance of the

transmission line - The same as the generator output impedance

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?

- A very high impedance
- A very low impedance
- The same as the characteristic impedance of the

line - The same as the output impedance of the generator

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?

- A very high impedance
- A very low impedance
- The same as the characteristic impedance of the

line - The same as the output impedance of the generator

E9F16 What is the primary difference between

foam-dielectric coaxial cable as opposed to

solid-dielectric cable, assuming all other

parameters are the same?

- Reduced safe operating voltage limits
- Reduced losses per unit of length
- Higher velocity factor
- All of these answers are correct

E4A07 Which of the following is an advantage

of using an antenna analyzer vs. a SWR bridge to

measure antenna SWR?

- Antenna analyzers automatically tune your antenna

for resonance - Antenna analyzers typically do not need an

external RF source - Antenna analyzers typically display a

time-varying representation of the modulation

envelope - All of these answers are correct

E4B12 How should a portable SWR analyzer be

connected when measuring antenna resonance and

feedpoint impedance?

- Loosely couple the analyzer near the antenna base
- Connect the analyzer via a high-impedance

transformer to the antenna - Connect the antenna and a dummy load to the

analyzer - Connect the antenna feed line directly to the

analyzer's connector

E9G01 Which of the following can be calculated

using a Smith chart?

- Impedance along transmission lines
- Radiation resistance
- Antenna radiation pattern
- Radio propagation

E4A08 Which of the following instruments would

be best for measuring the SWR of a beam antenna?

- A spectrum analyzer
- A Q meter
- An ohmmeter
- An antenna analyzer

E9G02 What type of coordinate system is used in

a Smith chart?

- Voltage circles and current arcs
- Resistance circles and reactance arcs
- Voltage lines and current chords
- Resistance lines and reactance chords

E9G03 Which of the following is often

determined using a Smith chart?

- Beam headings and radiation patterns
- Satellite azimuth and elevation bearings
- Impedance and SWR values in transmission lines
- Trigonometric functions

E9G04 What are the two families of circles and

arcs that make up a Smith chart?

- Resistance and voltage
- Reactance and voltage
- Resistance and reactance
- Voltage and impedance

E9G05 What type of chart is shown in Figure

E9-3?

- Smith chart
- Free-space radiation directivity chart
- Elevation angle radiation pattern chart
- Azimuth angle radiation pattern chart

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?

- Prime axis
- Reactance axis
- Impedance axis
- Polar axis

E9G07 On the Smith chart shown in Figure E9-3,

what is the only straight line shown?

- The reactance axis
- The current axis
- The voltage axis
- The resistance axis

E9G08 What is the process of normalization with

regard to a Smith chart?

- Reassigning resistance values with regard to the

reactance axis - Reassigning reactance values with regard to the

resistance axis - Reassigning impedance values with regard to the

prime center - Reassigning prime center with regard to the

reactance axis

E9G09 What third family of circles is often

added to a Smith chart during the process of

solving problems?

- Standing-wave ratio circles
- Antenna-length circles
- Coaxial-length circles
- Radiation-pattern circles

E9G10 What do the arcs on a Smith chart

represent?

- Frequency
- SWR
- Points with constant resistance
- Points with constant reactance

E9G11 How are the wavelength scales on a Smith

chart calibrated?

- In fractions of transmission line electrical

frequency - In fractions of transmission line electrical

wavelength - In fractions of antenna electrical wavelength
- In fractions of antenna electrical frequency

E9C04 Which of the following describes a basic

rhombic antenna?

- Unidirectional four-sided, each side one

quarter-wavelength long terminated in a

resistance equal to its characteristic impedance - Bidirectional four-sided, each side one or more

wavelengths long open at the end opposite the

transmission line connection - Four-sided an LC network at each corner except

for the transmission connection - Four-sided, each side of a different physical

length

E9C05 What are the main advantages of a

terminated rhombic antenna?

- Wide frequency range, high gain and high

front-to-back ratio - High front-to-back ratio, compact size and high

gain - Unidirectional radiation pattern, high gain and

compact size - Bidirectional radiation pattern, high gain and

wide frequency range

E9C06 What are the disadvantages of a terminated

rhombic antenna for the HF bands?

- The antenna has a very narrow operating bandwidth
- The antenna produces a circularly polarized

signal - The antenna requires a large physical area and 4

separate supports - The antenna is more sensitive to man-made static

than any other type

E9C07 What is the effect of a terminating

resistor on a rhombic antenna?

- It reflects the standing waves on the antenna

elements back to the transmitter - It changes the radiation pattern from

bidirectional to unidirectional - It changes the radiation pattern from horizontal

to vertical polarization - It decreases the ground loss

E9H04 What term describes station output

(including the transmitter, antenna and

everything in between), when considering

transmitter power and system gains and losses?

- Power factor
- Half-power bandwidth
- Effective radiated power
- Apparent power

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?

- 1977 watts
- 78.7 watts
- 420 watts
- 286 watts

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?

- 317 watts
- 2000 watts
- 126 watts
- 300 watts

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?

- 159 watts
- 252 watts
- 632 watts
- 63.2 watts

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?

- Only the most powerful transmitter
- Only commercial transmitters
- Each transmitter that produces 5 or more of its

maximum permissible exposure limit at accessible

locations - Each transmitter operating with a duty-cycle

greater than 50

E9D01 How does the gain of a parabolic dish

antenna change when the operating frequency is

doubled?

- Gain does not change
- Gain is multiplied by 0.707
- Gain increases 6 dB
- Gain increases 3 dB

E9D03 How does the beamwidth of an antenna vary

as the gain is increased?

- It increases geometrically
- It increases arithmetically
- It is essentially unaffected
- It decreases

E9D04 Why is 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 - So the antenna can be pointed away from

interfering signals - So the antenna can be positioned to cancel the

effects of Faraday rotation - To rotate antenna polarization to match that of

the satellite

E0A11 Which of these items might be a significant

hazard when operating a klystron or cavity

magnetron transmitter?

- Hearing loss caused by high voltage corona

discharge - Blood clotting from the intense magnetic field
- Injury from radiation leaks that exceed the MPE

limits - Ingestion of ozone gas from the cooling system

E0A10 What material found in some electronic

components such as high-voltage capacitors and

transformers is considered toxic?

- Polychlorinated biphenyls
- Polyethylene
- Polytetrafluroethylene
- Polymorphic silicon

E0A05 What is one of the potential hazards of

using microwaves in the amateur radio bands?

- Microwaves are ionizing radiation
- The high gain antennas commonly used can result

in high exposure levels - Microwaves often travel long distances by

ionospheric reflection - The extremely high frequency energy can damage

the joints of antenna structures

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?

- Use a calibrated antenna analyzer
- Use a hand calculator plus Smith-chart equations

to calculate the fields - Walk around under the antennas with a neon-lamp

probe to find the strongest fields - Use a computer-based antenna modeling program to

calculate field strength at accessible locations

E0A08 What does SAR measure?

- Synthetic Aperture Ratio of the human body
- Signal Amplification Rating
- The rate at which RF energy is absorbed by the

body - The rate of RF energy reflected from stationary

terrain

E0A02 When evaluating exposure levels from your

station at a neighbors home, what must you do?

- Make sure signals from your station are less than

the controlled MPE limits - Make sure signals from your station are less than

the uncontrolled MPE limits - Nothing you need only evaluate exposure levels

on your own property - Advise your neighbors of the results of your tests

E0A06 Why are there separate electric (E) and

magnetic (H) field MPE limits?

- The body reacts to electromagnetic radiation from

both the E and H fields - Ground reflections and scattering make the field

impedance vary with location - E field and H field radiation intensity peaks can

occur at different locations - All of these answers are correct

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?

- Its overall length must not exceed 1/4 wavelength
- It must be mounted more than 1 wavelength above

ground - It should be configured as a four-sided loop
- It should be one or more wavelengths long

E9H09 What is a receiving loop antenna?

- A large circularly-polarized antenna
- A small coil of wire tightly wound around a

toroidal ferrite core - One or more turns of wire wound in the shape of a

large open coil - Any antenna coupled to a feed line through an

inductive loop of wire

E9H10 How can the output voltage of a receiving

loop antenna be increased?

- By reducing the permeability of the loop shield
- By increasing the number of wire turns in the

loop and reducing the area of the loop structure - By reducing either the number of wire turns in

the loop or the area of the loop structure - By increasing either the number of wire turns in

the loop or the area of the loop structure

E9H11 Why is an antenna with a cardioid pattern

desirable for a direction-finding system?

- The broad-side responses of the cardioid pattern

can be aimed at the desired station - The response characteristics of the cardioid

pattern can assist in determining the direction

of the desired station - The extra side lobes in the cardioid pattern can

pinpoint the direction of the desired station - The high-radiation angle of the cardioid pattern

is useful for short-distance direction finding

E9H12 What is an advantage of using a shielded

loop antenna for direction finding?

- It automatically cancels ignition noise pickup in

mobile installations - It is electro-statically balanced against ground,

giving better nulls - It eliminates tracking errors caused by strong

out-of-band signals - It allows stations to communicate without giving

away their position

E9H05 What is the main drawback of a wire-loop

antenna for direction finding?

- It has a bidirectional pattern
- It is non-rotatable
- It receives equally well in all directions
- It is practical for use only on VHF bands

E9H07 Why is an RF attenuator desirable in a

receiver used for direction finding?

- It narrows the bandwidth of the received signal
- It eliminates the effects of isotropic radiation
- It reduces loss of received signals caused by

antenna pattern nulls - It prevents receiver overload from extremely

strong signals

E9H08 What is the function of a sense antenna?

- It modifies the pattern of a DF antenna array to

provide a null in one direction - It increases the sensitivity of a DF antenna

array - It allows DF antennas to receive signals at

different vertical angles - It provides diversity reception that cancels

multipath signals

E9H06 What is the triangulation method of

direction finding?

- The geometric angle of sky waves from the source

are used to determine its position - A fixed receiving station plots three headings

from the signal source on a map - Antenna headings from several different receiving

stations are used to locate the signal source - A fixed receiving station uses three different

antennas to plot the location of the signal source