Radio amateur examination q51 q150

4x4 Adventures
The Essentials:
MALAYSIAN
RADIO AMATUER EXAMINATION
SAMPLE QUESTIONS with Answers.
Q51~Q150
26th March 2019
Charliechong 黑豹 https://sems.skmm.gov.my/sems/

Charliechong 黑豹 https://sems.skmm.gov.my/sems/
黑豹
The PUMA
VHF 104.500MHz

Charliechong 黑豹
黑豹
The PUMA
VHF 104.500MHz
https://sems.skmm.gov.my/sems/

Charliechong
The handbook
黑豹

The Puma
Charliechong 黑豹 https://www.facebook.com/puma4x4https://sems.skmm.gov.my/sems/

Charliechong
Zello PTT Walkie Talkie
黑豹 https://play.google.com/store/apps/details?id=com.loudtalks&hl=en_US
Internet Based Walkie Talkie

Charliechong
The Magical Book of Amateur Radio Operator.
https://sems.skmm.gov.my/sems/

Charlie Chong https://sems.skmm.gov.my/sems/

Radio Amateur Examination
Questions &Answers
For Amateur Radio Services In Malaysia
https://www.skmm.gov.my/skmmgovmy/files/attachments/Guideline_Amateur_Radio_Service_2012.pdfCharliechong 黑豹

Charliechong
Pre-read or Watch Video- Thanks Freddy fro recommending.
黑豹 https://www.youtube.com/embed/RGluTpM7_K8

Charliechong
Pre-read or Watch Video
黑豹 http://pwarc.com/documents/2014-no-nonsense-tech-study-guide-v1.1.pdf

Charliechong
Stan Gibilisco- The Master Electronician
黑豹 http://webwork.utleon.edu.mx/Paginas/Documentos/Robotica/electronica/(ebook)%20Gibilisco,%20Stan%20-%20Teach%20Yourself%20Electricity%20and%20Electronics.pdf

Charliechong
Q54. In figure N7-1, if block 1 is a transceiver and block 3 is
a dummy antenna, what is block 2?
a) a terminal-node switch
b) an antenna switch
c) a telegraph key switch
d) a high-pass filter
My answer: b)
The correct answer: b)
黑豹 https://www.facebook.com/puma4x4

Charliechong
Q55. In figure N7-1, if block 1 is a transceiver and block 2 is
an antenna switch. what is block 3?
a) a terminal-node switch
c) a telegraph key switch
b) an SWR meter
d) a dummy antenna
My answer: d)
The correct answer: d)

Charliechong
Q56. In figure N7-3, If block 1 is a transceiver and block 2 is
an SWR meter, what Is block 3?
a) an antenna switch
b) an antenna tuner
c) a key-click liter
d) a terminal-node controller
My answer: a)

Charliechong
Q57. What circuit is pictured in figure T7-1 if block 1 is a
variable frequency oscillator?
a) a packet radio transmitter
b) a crystal-controlled transmitter
c) a single-sideband transmitter
d) a VFO controlled transmitter
My answer: d)

Charliechong
Q58. What circuit is pictured In figure 17·1 if block 1 is a
crystal oscillator?
a) a crystal-controlled transmitter
b) a VFO controlled transmitter
c) a single-sideband transmitter
d) a CW transceiver
My answer: a)
The correct answer: a)

Charliechong
Q59. The commonly used amateur radio single side band
mode is defined as:
a) F3E c) J3E
b) A3E d) G3E
My answer: c)
The correct answer: c)
Q60. Frequency modulation using voice is termed:
a) F1A c) F3C
b) F2A d) F3E
My answer: d)

Class of
Transmission
First symbol Second symbol Third symbol
A3E A i) Double-
sideband
A single channel containing analogue
information
E Telephony
(including sound
broadcasting)
F1A F i) Frequency
modulation
1 A single channel containing
quantized or digital information without
the use of a modulating sub-carrier
A Telegraphy – for
aural reception
F2A 2 A single channel containing
quantized or digital information with
F3E A single channel containing analogue
information
E Telephony
(including sound
broadcasting)J3E iv) Single-
sideband,
suppressed carrier
information
R3E iii) Single-sideband,
reduced or
variable level
carrier
Charliechong 黑豹
Aural- relating to the ear or the sense of hearing.
https://www.skmm.gov.my/skmmgovmy/files/attachments/Guideline_Amateur_Radio_Service_2012.pdf

Class of
Transmission
A3E A i) Double-
sideband
information
E Telephony
(including sound
broadcasting)
F1A F i) Frequency
modulation
aural reception
information
E Telephony
(including sound
sideband,
suppressed carrier
information
reduced or
variable level
carrier
Charliechong 黑豹
https://www.skmm.gov.my/skmmgovmy/files/attachments/Guideline_Amateur_Radio_Service_2012.pdf
In most telemetering systems, modulation is carried out in two
stages. First, the signal modulates a subcarrier (a radio-frequency
wave the frequency of which is below that of the final carrier), and
then the modulated subcarrier in turn modulates the output carrier.
Frequency modulation is used in many of these systems to impress
the telemetry information on the subcarrier. If frequency-division
multiplexing is used to combine a group of these frequency-
modulated subcarrier channels, the system is known as an FM/FM
system.
https://www.britannica.com/technology/telemetry#ref268920

Charliechong 黑豹 https://www.facebook.com/puma4x4
F3E
Frequency
Modulated
Single Channel
Analog
Telephony
Class of Transmission

Charliechong
Class of Transmission
Double/Single
Sideband/ FM
Digital/ Analog Telephony/
Telegraphy
A
F
J
R
1
2
3
E
A

Charliechong
Subcarrier
A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to
send additional information. Examples include the provision of colour in a black and
white television system or the provision of stereo in a monophonic radio broadcast.
There is no physical difference between a carrier and a subcarrier; the "sub" implies
that it has been derived from a carrier, which has been amplitude modulated by a
steady signal and has a constant frequency relation to it.
黑豹 https://en.wikipedia.org/wiki/Subcarrier

Charliechong 黑豹 https://www.britannica.com/technology/telemetry#ref268920
Transmission.
A process called modulation is used to impress the information on the carrier frequency. Of
the many design choices that must be made, that of the modulation method is among the
most important. Not only does it have a direct influence on system performance but it also
tends to define areas of design in both the sender and the receiver. Modulation methods
fall into two divisions. The first includes amplitude and frequency modulation (as in
commercial AM and FM broadcasting) and related types. These related types include two
pulse-based methods in which several pulses are spaced out in time, each pulse
representing one information channel. The two types are pulse-width (or pulse-duration)
modulation and pulse-position modulation. In the first, the information produces variations
in the width (or duration) of the pulse; in the second, the variation is in the position of the
pulse with respect to time. In the second main class, pulse-code modulation, the
information is coded digitally into groups of pulses and then transmitted.
In most telemetering systems, modulation is carried out in two stages. First, the signal
modulates a subcarrier (a radio-frequency wave the frequency of which is below that of the
final carrier), and then the modulated subcarrier in turn modulates the output carrier.
Frequency modulation is used in many of these systems to impress the telemetry
information on the subcarrier. If frequency-division multiplexing is used to combine a group
of these frequency-modulated subcarrier channels, the system is known as an FM/FM
system.

Charliechong
Frequency Modulation with modulating Subcarrier
黑豹 https://en.wikipedia.org/wiki/FM_broadcasting
Typical spectrum of composite baseband signal

Charliechong
Q61. What is the advantage in using the international
telecommunication union (ITU) phonetic alphabet when
identifying your station
a) the words are internationally recognized substitutes for letters
b) there is no advantage
c) the words have been chosen to be easily pronounced by Asian cultures
d) it preserves traditions begun In the early days of Amateur Radio
My answer: a)

ITU Phonetic Alphabet

Charliechong
Question from 62 to 64 relates to this diagram below:

Q62. The antenna in this diagram has two equal lengths of
wire shown as x forming a dipole between insulators. The
optimum operating frequency will be when the
a) length X+X equals the signal wavelength
b) dimensions are changed with one leg doubled in length
c) length X is a little shorter than one-half of the signal wavelength
d) antenna has one end grounded
My answer: c)
Q63. The antenna in this diagram can be made to operate on
several bands if the following item is installed at the points
shown at x in each wire
a) A capacitor c) a fuse
b) an inductor d) a parallel-tuned trap
My answer: b)

Charliechong
Tune Trapper
The Tune Trapper is a hidden FM antenna that works! Mount in almost any vehicle,
boat, RV or motorcycle. The Tune Trapper antenna was designed to be hidden. Mount
it anywhere, in any position, in steel or fiberglass; it's flexible and can be bent 10 to 20
degrees, and works awesome inside H-D fairings! The Tune Trapper is a full 1/2 wave
helical dipole antenna, hand tuned to resonance with special instruments and requires
no ground. It uses 95% braided shield cable for virtual elimination of EMI electrical
noise caused by engines, fans, wipers, etc. These hand-tuned USA made antennas
require no power; your radio has all the preamp it needs built in, it's just looking for a
properly tuned antenna to make it rock.
黑豹 http://www.phatperformanceparts.com/Tune_Trapper_Hidden_Antenna_p/ky-853.htm

Charliechong
Q64. The physical length of the antenna shown in this
diagram can be shortened and the electrical length
maintained, if one of the following item is added at the
points she at x in each wire
a) an inductor c) an insulator
b) a capacitor d) a resistor
My answer: a)

Charliechong
Q65. Magnetic and electric fields about an antenna are
a) parallel to each other
b) determined by the type of antenna used
c) perpendicular to each other
d) variable with the time of day
My answer: c)
Q66. An SWR meter is inserted into a perfectly matched
transmitter/antenna system. The value shown should
indicate:
a) 1 ON reflected power
C) 1:0 VSWR
c) 1:1 VSWR
d) 0:1 VSWR
My answer: c)

Charliechong
Q67. A ground-plane antenna emits a
a) horizontally polarized wave
b) elliptically polarized wave
c) axially polarized wave
d) vertically polarized wave
My answer: c)

Charliechong
Q67. A ground-plane antenna emits a
a) horizontally polarized wave
b) elliptically polarized wave
c) axially polarized wave
d) vertically polarized wave
My answer: c)
vertically polarized wave
But a vertical "whip antenna" or AM
broadcast tower used as an antenna
element (again, for observers horizontally
displaced from it) will transmit in the
vertical polarization.

Charliechong
Polarizations

Charliechong
Monopole Antenna
For a monopole antenna, the Earth acts as a ground plane to reflect radio waves
directed downwards, making them seem to come from an image antenna.

Charliechong
What is Antenna Ground Plane?
As the name indicates the antenna ground plane acts as a simulated ground. It is
found that for a monopole antenna like a quarter wavelength vertical, the ground acts
as a plane to reflect the radio waves so that an image of the top half of the antenna is
seen in the Earth. It is possible to simulate this function by replacing the real earth with
a conducting plane. To function as an antenna ground plane, the conducting surface
must extend for least a quarter wavelength from the base of the antenna.
黑豹 https://www.electronics-notes.com/articles/antennas-propagation/grounding-earthing/antenna-ground-plane-theory-design.php
In reality it is not necessary to have a full
circular conducting plate for a ground plane.
This would be difficult to manage in terms
cost and also the wind resistance. In stead it
is normally sufficient to have a ground plane
consisting of a number of quarter wavelength
radials. Often four conducting radials are
used and these often provide a sufficient
simulation of the complete circular ground
plane..
Vertical antenna with ground plane radials

Charliechong
Ground Plane Antenna
With stationary whips mounted on structures, an artificial "ground plane" consisting of
three or four rods a quarter-wavelength long extending horizontally from the base of
the whip is often used. This provides a stable input impedance and pattern by helping
prevent RF currents in the supporting mast and along the outside of the feed line. This
type of antenna is called a ground plane antenna. Often the ground plane rods are
sloped downward toward the ground, which lowers the main lobe of the radiation
pattern and increases the normal 36.8 ohm radiation resistance closer to 50 ohms to
provide a better impedance match with standard 50 ohm coaxial cable feedline.
Gain and radiation resistance
A quarter wave vertical antenna working against a perfect infinite ground will have a
gain of 5.19 dBi and about 36.8 ohms of radiation resistance. Whips mounted on
vehicles use the metal skin of the vehicle as a ground plane. In hand-held devices
usually no explicit ground plane is provided, and the ground side of the antenna's feed
line is just connected to the ground on the device's circuit board. Therefore, the radio
itself, and possibly the user's hand, serves as a rudimentary ground plane. Since
these are no larger than the size of the antenna itself, the combination of whip and
radio often functions more as an asymmetrical dipole antenna than as a monopole
antenna. The gain will suffer somewhat compared to a half wave metallic diople or a
whip with a well defined ground plane.

Charliechong
Radio Antenna Theory
In telecommunication, a ground plane is a flat or nearly flat horizontal conducting surface
that serves as part of an antenna, to reflect the radio waves from the other antenna
elements. The plane does not necessarily have to be connected to ground. Ground
plane shape and size play major roles in determining its radiation characteristics
including gain.
For a monopole antenna, the Earth acts as a ground plane to reflect radio waves
directed downwards, making them seem to come from an image antenna.
To function as a ground plane, the conducting surface must be at least a quarter of the
wavelength (λ/4) of the radio waves in diameter. In lower frequency antennas, such as
the mast radiators used for broadcast antennas, the Earth itself (or a body of water such
as a salt marsh or ocean) is used as a ground plane. For higher frequency antennas, in
the VHF or UHF range, the ground plane can be smaller, and metal disks, screens and
wires are used as ground planes. At upper VHF and UHF, the metal skin of a car or
aircraft can serve as a ground plane for whip antennas projecting from it. In microstrip
antennas and printed monopole antennas an area of copper foil on the opposite side of
a printed circuit board serves as a ground plane. The ground plane doesn't have to be a
continuous surface. In the ground plane antenna style whip antenna, the "plane"
consists of several wires λ/4 long radiating from the base of a quarter-wave whip
antenna.

Charliechong
The radio waves from an antenna element that reflect off a ground plane appear to
come from a mirror image of the antenna located on the other side of the ground plane.
In a monopole antenna, the radiation pattern of the monopole plus the virtual "image
antenna" make it appear as a two element center-fed dipole antenna. So a monopole
mounted over an ideal ground plane has a radiation pattern identical to a dipole
antenna. The feedline from the transmitter or receiver is connected between the
bottom end of the monopole element and the ground plane. The ground plane must
have good conductivity; any resistance in the ground plane is in series with the
antenna, and serves to dissipate power from the transmitter.

Charliechong
Effects Of A Finite Size Ground Plane On The Monopole
Antenna
In practice, monopole antennas are used on finite-sized ground planes. This affects
the properties of the monopole antennas, particularly the radiation pattern. The
impedance of a monopole antenna is minimally affected by a finite-sized ground plane
for ground planes of at least a few wavelengths in size around the monopole. However,
the radiation pattern for the monopole antenna is strongly affected by a finite sized
ground plane. The resulting radiation pattern radiates in a "skewed" direction, away
from the horizontal plane. An example of the radiation pattern for a quarter-wavelength
monopole antenna (oriented in the +z-direction) on a ground plane with a diameter of
3 wavelengths is shown in the following Figure:
黑豹 http://www.antenna-theory.com/antennas/monopole.php
Note that the resulting radiation pattern for
this monopole antenna is still omnidirectional.
However, the direction of peak-radiation has
changed from the x-y plane to an angle
elevated from that plane. In general, the large
the ground plane is, the lower this direction of
maximum radiation; as the ground plane
approaches infinite size, the radiation pattern
approaches a maximum in the x-y plane.

Charliechong
Monopole Antennas
A monopole antenna is a type of dipole antenna formed by replacing one half of the
dipole antenna with the ground plane at a right angle to the remaining half. If the
ground plane is large enough, the monopole behaves exactly like a dipole because its
reflection in the ground plane forms the missing half of the dipole.
黑豹 https://www.sciencedirect.com/topics/computer-science/monopole-antenna

Charliechong
Types of Antenna
Antennas can be classified as omnidirectional, radiating energy approximately equally
in all directions, or directional, where energy radiates more along one direction than
others. (Antennas are reciprocal, so the same effect occurs for reception of radio
waves.) A completely uniform omnidirectional antenna is not physically possible. Some
antenna types have a uniform radiation pattern in the horizontal plane, but send little
energy upward or downward. A "directional" antenna usually is intended to maximize
its coupling to the electromagnetic field in the direction of the other station.
A vertical antenna or whip antenna radiates in all directions horizontally, but sends
less energy upward or downward.
Similarly, a dipole antenna oriented horizontally sends little energy parallel to the
conductor; this region is called the antenna null.
黑豹 https://en.wikipedia.org/wiki/Antenna_(radio)#Polarization

Charliechong
Half-wave dipole antenna
The dipole antenna, which is the basis for most antenna designs, is a balanced
component, with equal but opposite voltages and currents applied at its two terminals.
A monopole antenna
The vertical antenna is a monopole antenna, not balanced with respect to ground. The
ground (or any large conductive surface) plays the role of the second conductor of a
dipole. Since monopole antennas rely on a conductive surface, they may be mounted
with a ground plane to replicate the effect of being mounted on the Earth's surface.

Charliechong
Dipole Antenna
Animation of a half-wave dipole antenna transmitting radio waves, showing the electric
field lines. The antenna in the center is two vertical metal rods, with an alternating
current applied at its center from a radio transmitter (not shown). The voltage charges
the two sides of the antenna alternately positive (+) and negative (−). Loops of electric
field (black lines) leave the antenna and travel away at the speed of light; these are
the radio waves.

Charliechong
Dipole Antenna
Animated diagram of a half-wave dipole antenna receiving energy from a radio wave.
The antenna consists of two metal rods connected to a receiver R. The electric field (E,
green arrows) of the incoming wave pushes the electrons in the rods back and forth,
charging the ends alternately positive (+) and negative (−). Since the length of the
antenna is one half the wavelength of the wave, the oscillating field induces standing
waves of voltage (V, represented by red band) and current in the rods. The oscillating
currents (black arrows) flow down the transmission line and through the receiver
(represented by the resistance R).

Charliechong
Dipole Antenna
Standing waves on a half wave dipole driven at its resonant frequency. The waves are
shown graphically by bars of color (red for voltage, V and blue for current, I) whose
width is proportional to the amplitude of the quantity at that point on the antenna.

Charliechong
Vertically Polarized Wave

Charliechong
The polarization of an antenna refers to the orientation of the electric field it produces.
Polarization is important because the receiving antenna should have the same
polarization as the transmitting antenna to maximize received power.
黑豹 http://www.urel.feec.vutbr.cz/~raida/multimedia/index.php?nav=10-4-A&lang=en

Charliechong
http://www.mysearch.org.uk/website1/images/animations/476.2.anim.gif
黑豹 http://www.urel.feec.vutbr.cz/~raida/multimedia/index.php?nav=10-4-A&lang=en

Charliechong 黑豹 https://www.usna.edu/EE/ee434/Handouts/EE302%20Lesson%2013%20Antenna%20Fundamentals.pdf
vertically polarized wave
But a vertical "whip antenna" or AM
broadcast tower used as an antenna
element (again, for observers horizontally
displaced from it) will transmit in the
polarization as the transmitting antenna to maximize received power

Charliechong
http://66.media.tumblr.com/d2736a19337e1bcd3eb1f78342bd00f0/tumblr_mf8q14Vix4
1rd0rbzo1_500.gif
Ground
λ/4

Charliechong
Polarization (also polarization) is a property applying to transverse waves that
specifies the geometrical orientation of the oscillations. In a transverse wave, the
direction of the oscillation is perpendicular to the direction of motion of the wave.
Radio transmission and reception
All radio (and microwave) antennas used for transmitting or receiving are intrinsically
polarized. They transmit in (or receive signals from) a particular polarization, being
totally insensitive to the opposite polarization; in certain cases that polarization is a
function of direction. Most antennas are nominally linearly polarized, but elliptical and
circular polarization is a possibility. As is the convention in optics, the "polarization" of
a radio wave is understood to refer to the polarization of its electric field, with the
magnetic field being at a 90 degree rotation with respect to it for a linearly polarized
wave.
黑豹 https://en.wikipedia.org/wiki/Polarization_(waves)
Radio transmission and reception
All radio (and microwave) antennas used for transmitting or receiving are intrinsically polarized. They transmit in (or receive signals from) a particular polarization, being totally insensitive to the opposite polarization; in certain cases that polarization is a function of direction. Most
antennas are nominally linearly polarized, but elliptical and circular polarization is a possibility. As is the convention in optics, the "polarization" of a radio wave is understood to refer to the polarization of its electric field, with the magnetic field being at a 90 degree rotation with
respect to it for a linearly polarized wave.
The vast majority of antennas are linearly polarized. In factit can be shown from considerations of symmetry that an antenna that lies entirely in a plane which also includes the observer, can only have its polarization in the direction of that plane. This applies to many cases,
allowing one to easily infer such an antenna's polarization at an intended direction of propagation. So a typical rooftop Yagi or log-periodic antenna with horizontal conductors, as viewed from a second station toward the horizon, is necessarily horizontally polarized. But a
vertical "whip antenna" or AM broadcast tower used as an antenna element (again, for observers horizontally displaced from it) will transmit in the vertical polarization. A turnstile antenna with its four arms in the horizontal plane, likewise transmits horizontally polarized radiation
toward the horizon. However, when that same turnstile antenna is used in the "axial mode" (upwards, for the same horizontally-oriented structure) its radiation is circularly polarized. At intermediate elevations it is elliptically polarized.
Polarization is important in radio communications because, for instance, if one attempts to use a horizontally polarized antenna to receive a vertically polarized transmission, the signal strength will be substantially reduced (or under very controlled conditions, reduced to nothing).
This principle is used in satellite television in order to double the channel capacity over a fixed frequency band. The same frequency channel can be used for two signals broadcast in opposite polarizations. By adjusting the receiving antenna for one or the other polarization,
either signal can be selected without interference fromthe other.
Especially due to the presence of the ground, there are some differencesin propagation (and also in reflections responsible for TV ghosting) between horizontal and vertical polarizations. AM and FM broadcast radio usually use vertical polarization, while television uses
horizontal polarization. At low frequencies especially, horizontal polarization is avoided. That is because the phase of a horizontally polarized wave is reversed upon reflection by the ground. A distant station in the horizontal direction will receive both the direct and reflected
wave, which thus tend to cancel each other. This problem is avoided with vertical polarization. Polarization is also important in the transmission of radar pulses and reception of radar reflections by the same or a differentantenna. For instance, back scattering of radar pulses by
rain drops can be avoided by using circular polarization. Just as specular reflection of circularly polarized light reverses the handedness of the polarization, as discussed above, the same principle applies to scattering by objects much smaller than a wavelength such as rain
drops. On the other hand, reflection of that wave by an irregular metal object (such as an airplane) will typically introduce a change in polarization and (partial) reception of the return wave by the same antenna.
The effectof freeelectrons in the ionosphere, in conjunction with the earth's magnetic field, causes Faraday rotation, a sort of circular birefringence. This is the same mechanism which can rotate the axis of linear polarization by electrons in interstellar space as mentioned below.
The magnitude of Faraday rotation caused by such a plasma is greatly exaggerated at lower frequencies, so at the higher microwave frequencies used by satellites the effectis minimal. However medium or short wave transmissions received following refraction by the
ionosphere are strongly affected. Since a wave's path through the ionosphere and the earth's magnetic field vector along such a path are rather unpredictable, a wave transmitted with vertical (or horizontal) polarization will generally have a resulting polarization in an arbitrary
orientation at the receiver.

Charliechong
The vast majority of antennas are linearly polarized. In fact it can be shown from
considerations of symmetry that an antenna that lies entirely in a plane which also
includes the observer, can only have its polarization in the direction of that plane. This
applies to many cases, allowing one to easily infer such an antenna's polarization at
an intended direction of propagation.
So a typical rooftop Yagi or log-periodic antenna with horizontal conductors, as viewed
from a second station toward the horizon, is necessarily horizontally polarized.
But a vertical "whip antenna" or AM broadcast tower used as an antenna
element (again, for observers horizontally displaced from it) will transmit in the
A turnstile antenna with its four arms in the horizontal plane, likewise transmits
horizontally polarized radiation toward the horizon.
However, when that same turnstile antenna is used in the "axial mode" (upwards, for
the same horizontally-oriented structure) its radiation is circularly polarized. At
intermediate elevations it is elliptically polarized.
黑豹 https://en.wikipedia.org/wiki/Polarization_(waves)

Charliechong
A "vertically polarized" electromagnetic wave of wavelength λ has its electric field
vector E (red) oscillating in the vertical direction. The magnetic field B (or H) is always
at right angles to it (blue), and both are perpendicular to the direction of propagation
(z).

Charliechong
A circularly polarized wave as a sum of two linearly polarized components 90° out of
phase. https://upload.wikimedia.org/wikipedia/commons/4/41/Rising_circular.gif

Charliechong
Animation showing four different polarization states and two orthogonal projections.
https://upload.wikimedia.org/wikipedia/commons/0/08/Wave_Polarisation.gif

Charliechong
Q68. What Is a cubical quad antenna
a) Four straight, parallel elements in line with each other, each approximately ½
electrical wavelength long
b) Two or more parallel four-sided wire loops, each approximately one electrical
wavelength long
c) a vertical conductor ½ electrical wavelength high, fed at the bottom
d) a center fed wire V wavelength long.
My answer: b)

Charliechong
Cubical Quad Antenna

Charliechong
Cubical Quad Antenna
黑豹 https://www.electronics-notes.com/articles/antennas-propagation/cubical-quad-antenna/2-two-metre-quad-design-construction.php
?λ

Charliechong
A 4-element amateur radio quad antenna. The two men working on it show the scale.
The wire loops are almost invisible, suspended on the ends of the crossed supports.
黑豹

Charliechong
Q69. The "RMS value" of a sine-wave signal is:
a) half the peak voltage
b) 1.414 times the peak voltage
c) the peak-to-peak voltage
d) 0.707 times the peak voltage
My answer: d)

Charliechong
Q70. The major mode of propagation at VHF over long
distances Is known as:
a) tropospheric propagation
b) ionospheric propagation
c) ground wave propagation
d) additive propagation
My answer: b)
Keywords: VHF
黑豹
Tropospheric propagation : Tropospheric propagation is normally
associated with the VHF and UHF amateur bands. It occurs when there is a
sharp change in the refractive index of the air with increasing height. This can
be associated with weather front and as such a good eye on the weather can
be very helpful. Note on Tropospheric propagation:
The troposphere is the region of the atmosphere closest to the earth. It is found
that the refractive index of the air reduces slightly with increasing altitude. This
effect can also be enhanced and modified by weather conditions. As
electromagnetic waves bend towards the areas of high refractive index, it is
found that radio signals are affected by these changes and can travel over
distances beyond the horizon.
https://www.electronics-notes.com/articles/ham_radio/amateur-propagation/basics.php

Charliechong
Amateur Radio Operating for Propagation Modes
There are many different forms of radio propagation that can be used for amateur
radio - some specialist propagation modes require specific operating procedures,
frequencies, etc.
Amateur radio & propagation includes:
Propagation & techniques basics, Operating via sporadic E, Meteor scatter, Auroral-
propagation operation, Moonbounce EME operation.
There are many different forms of radio propagation that can be used for amateur
radio contacts. Some utilise the more normal forms of radio propagation, and the
procedures, frequencies and the like are well know. However other forms of
propagation are less widely used, or they may occur occasionally and more specialist
procedures, specific frequencies and other requirements may be needed.
It is the operating procedures, frequencies and techniques that are described in this
series of pages.
黑豹 https://www.electronics-notes.com/articles/ham_radio/amateur-propagation/basics.php

Charliechong
Amateur radio propagation modes used.
One of the interesting aspects of ham radio, is the enormous variety of different
propagating modes that can be used.
The band, time of day, time of year, weather and position in the sunspot cycle can all
have an effect, dependent upon the type of propagation mode used.
Knowing how to anticipate the different forms of propagation can help ensure that the
best chances are presented. Then knowing the different operating procedures along
with the frequencies, and optimum modes can ensure that the best chance of making
contacts is gained.
Some of the main forms of propagation are detailed below:

Charliechong
Ground wave propagation: Although ground wave propagation is used
for the medium and long wave broadcast bands, it is not particularly widely used for
ham radio communications. It is used on 160 metres and 80 metres, but in view of the
fact that with increasing frequency signals propagating via this mode are increasingly
attenuated, it is not particularly widely used.
Note on Ground Wave propagation:
Ground wave propagation occurs when signals follow the contour of the Earth,
bending so that the signals are able to be detected beyond the horizon. It is this form
of propagation that is used by LF and MF, Long Wave and Medium Wave Band
broadcast stations..
Read more about
Ground Wave propagation

Charliechong
Ionospheric propagation: Ionospheric propagation is the form of
propagation that is widely used on the short wave amateur bands. Using refractions of
the signals via the ionosphere it is possible for global communications to be gained. To
make the most of these bands, the use of propagation charts as well as looking at the
ionospheric indicators provides a good understanding of what is happening. However
it is also essential to have a good ‖feel‖ for the different bands.
Note on Ionospheric propagation:
The ionosphere exists in the upper reaches of the atmosphere extending to altitudes
of 400 km or more. The different regions of the ionosphere can affect radio signals
refracting them so that they return to Earth. In this way, signals can be heard at
distances ranging from a few hundred kilometers to the other side of the globe.
Read more about Ionospheric propagation

Charliechong 黑豹 https://www.electronics-notes.com/articles/ham_radio/amateur-propagation/basics.php

Charliechong
The handbook

Charliechong
Grey line propagation: One form of propagation that can yield some
amazing results is called grey line propagation. If a signal path follows the shadow line
between dark and light, it receives significant enhancements, and it can be used to
very good advantage if used with a little inside understanding.

Charliechong
Tropospheric propagation : Tropospheric propagation is normally
associated with the VHF and UHF amateur bands. It occurs when there is a sharp
change in the refractive index of the air with increasing height. This can be associated
with weather front and as such a good eye on the weather can be very helpful.
Note on Tropospheric propagation:
The troposphere is the region of the atmosphere closest to the earth. It is found that
the refractive index of the air reduces slightly with increasing altitude. This effect can
also be enhanced and modified by weather conditions. As electromagnetic waves
bend towards the areas of high refractive index, it is found that radio signals are
affected by these changes and can travel over distances beyond the horizon.

Charliechong
Q71. The dielectric of an open wire feeder is usually:
a) air c) polythene
b) rubber d) water
My answer: a)
Q72. What Is the lowest ionospheric region?
a) F1 c) F2
b) D d) E
My answer: b)

Charliechong
The handbook
黑豹 http://slideplayer.com/slide/10608560/

Charliechong
Ionospheric Reflection

Charliechong
Q73. What is one of the most significant problems
associated with mobile transceivers
a) ignition noise
b) radar interference
c) Doppler shift
d) mechanical vibrations
My answer: c)
ignition
noise?

Charliechong
Q74. If you ore told that your amateur station is causing
television interference, what should you do?
a) first make sure that your station is operating properly, and that it does not cause
interference to your own television
b) immediately tum off your transmitter and contact the nearest MCMC office for
assistance
c) connect a high-pass filter to the transmitter output and a low-pass filter to the
antenna-input terminals of the television
d) continue operating normally, because you have no reason to worry about the
interference
My answer: a)

your amateur
station is causing
television
interference

Charliechong
Q75. What should be done if a properly operating amateur
station is the cause or interference to a nearby telephone
a) make internal adjustments to the telephone equipment
b) install RFI filters at the affected telephone
c) stop transmitting whenever the telephone is in use
d) ground and shield the local telephone distribution amplifier
My answer: b)

Q76. What is a CTCSS (or PL) tone?
a) a special signal used for telecommand control of model craft
b) a sub-audible tone, added to a carrier, which may cause a receiver to accept a
signal
c) a tone used by repeaters lo mark the end of a transmission
d) a special signal used for telemetry between amateur 8 space stations and earth
stations
My answer: b)
Q77. When conversing via a VHF or UHF repeater you
should pause between overs to allows for
a) urgent and emergency traffic
b) to cool down the repeater
c) other stations to join in the QSO
d) answer a & b above
My answer: a)
QSO * Can you communicate with ... directly (or through...)?
https://www.qsl.net/w5www/qcode.html

Charliechong
Q78. The ‘S meter' on a receiver
a) indicates where the squelch control should be set
b) indicates the standing wave ratio
c) indicates the state of the battery voltage
d) indicates relative Incoming signal strengths
My answer: d)
Q79. You are mobile and talking through a VHF repeater.
The other station reports that you keep 'dropping out’ This
means
a) your signal is drifting lower in frequency
b) your signal does not have enough strength to operate the repeater
c) your voice is too low-pitched to be understood
d) you are not speaking loudly enough
My answer: a)

Charliechong
Q80. Morse code is usually transmitted by radio as:
a) an interrupted carriers
b) a voice modulated carrier 90
c) a continuous carrier
d) a series of clicks
My answer: a)

Charliechong
Q81. SSS transmissions:
a) occupy about twice the bandwidth of AM transmission
b) contain more information than AM transmissions
c) occupy about half the bandwidth of AM transmissions
d) are compatible with FM transmissions
My answer: c)
Q82. When using data transmission in the 144 MHz band or
above, the callsign must be sent:
a) using RTTY
b) every 10 minutes
c) at least every 15 minutes
d) in ASCII
My answer: b)

Charliechong
Q83. In the event of a national disaster which of the
following bands can be used by non-amateurs in the
disaster area in accordance with the Licensing conditions?
a) 144-146 MHz c) 29.0-29.7 MHz
b) 146-148MHz d) none of these
My answer: ?)
Q84. The fifth harmonic of a 144 MHz transmission lies to:
a) another amateur radio
b) the UHF TV band
c) a FM radio broadcast band
d) A MOD band
My answer: b)
The correct answer: No answer)

Charliechong
144-146 MHz

Charliechong
Q85. Power supplies to RF power amplifier should:
a) be open wires c) be AF filtered
b) Be RF filtered d) be inductively coupled
My answer: b)
Q86. The height of the F1 layer is about
a) 80km c) 120km
b) 200 km d) 300 km
My answer: c)

Charliechong
Ionosphere
黑豹 https://en.wikipedia.org/wiki/Ionosphere

Charliechong
Q87. The skip zone is where the ground wave:
a) is enhanced
b) is reflected
c) diminished and the reflected wave has not returned to earth
d) and reflected wave combine
My answer: c)
Q88. Typical dielectric for coaxial cable is:
a) rubber b) porcelain
C) ceramic d) polythene
My answer: d)

Charliechong 黑豹 http://www.tpub.com/neets/book10/40l.htm

Charliechong
Q89. The side of a quad antenna is:
a) quarter wavelength
b) a half wavelength
c) three quarters d a wavelength
d) a full wavelength
My answer: d)
Q90. The easiest AC amplitude measurement to take direct
from an oscilloscope screen is:
a) RMS values
b) average values
c) peak values
d) peak to peak values
My answer: d)
The correct answer: no answer)

Charliechong
Q91. A SWR meter Is used to check:
a) transmitter efficiency
b) harmonic output
c) transmitter band width
d) transmitter to antenna matching
My answer: d)
Q92. The equivalent DC battery voltage to give the same
heating effect as a 12V (rms) sine wave source is:
a) SV b) 84V
c) 12V d) 17V
My answer: d)

Charliechong
Q93. The prime document for the administration of the
amateur service in Malaysia is the:
a) Radio Regulations, 1985
b) Broadcasting ACI
c) Radio Amateur Handbook
d) Multimedia Commission Ad, 1998
My answer: d)
Q94. If an amateur radio licensee is absent overseas, the
base station may be used by:
a) Any member of the Immediate family to maintain contact with only the licensee
b) Any amateur radio licensee but with consent
c) The immediate family to communicate with amateur radio licensee
d) None of the above
My answer: b)

Charliechong
Q95. The regulatory authority in Malaysia on amateur radio
is the:
a) Malaysian Amateur Radio Transmitters Society
b) Malaysian Communications and Multimedia Commission (MCMC)
c) International Amateur Radio Union (IARU)
d) Prime Minister(s Department
My answer: b)
Q96. Which education qualification exempt the holder from
the radio amateur examination?
a) Four credits il Sijil Pelajaran Malaysia subjects
b) Four passes in University undergraduate subjects
c) A principle in Sijil Tinggi Pelajaran Malaysia Physics and Mathematics
d) There is no exemption for any education qualification
My answer: d)

Charliechong
Q97. To whom may an amateur radio station licensee sell
amateur radio equipment:
a) To any person interested in amateur radio
b) To any person who is possession of a Radio Dealers License or to a person who is
In possession of a Amateur Radio License
c) To any person who is possession of a radio broadcast station license
d) To a person who has a foreign Citizen Band License
My answer: b)
Q98. Power supplies to RF power amplifiers should:
a) be open wires
b) be AF filtered
c) be RF filtered
d) be inductively coupled
My answer: c)

Charliechong
Q99. The value of a resistor to drop 100 volts with a current
of 0.8 milliampere is:
a) 125 ohm c) 1250 ohm
b) 125 kilo-ohm d) 1.25 kilo-ohm
V=IR
R=V/I = 100/(0.8) x1000 =
My answer: b)
Q100. If a current of 2 amperes flows through a 50ohm
resistor, what is the voltage across the resistor?
a) 25 volts c) 100volts
b) 52 volts d) 200volts
V=IR = 2 x 50 = 100volts
My answer: c)

Charliechong
Q101. The effective resistance of three 24 Ohm resistors
connected in parallel is:
a) 8ohms c) 12 ohms
b) 36ohms d) 72ohms
1/R = 1/R1 + 1/R2 + 1/R3 = 3(1/24)
R = [3(1/24)]-1
My answer: a)
Q102. An electric current passing through a wire will
produce around the conductor:
a) An electric field c) a super conductor
b.) A magnetic field d) a semiconductor
My answer: b)

Charliechong
Q103. The unit of impedance is the:
a) ampere c) Henry
b) farad d) ohm
My answer: c)
The actual correct answer is c)
XL = ωL = 2πfL
https://en.wikipedia.org/wiki/Electrical_reactance
Q104. One kilo-ohm is:
a) 10ohm c) 0.001 ohm
b) 0.01 ohm d) 1000ohm
My answer: d)

Charliechong
Q105. The watt is the unit of
a) Power
b) magnetic flux
c) electromagnetic field strength
d) breakdown voltage
My answer: a)
Q106. The unit of resistance is the:
a) farad c) ohm
b) watt d) resistor
My answer: c)

Charliechong
Q107. Radio wave polarization Is defined by the orientation
of the radiated:
a) magnetic field c) electric field
b) inductive field d) capacitive field
My answer: c)
Q108. Starting at a positive peak. how many times does a
sine wave cross the zero axis in one complete cycle:
a) 180 tines c) 2 times
b) 4times d) 360 times
My answer: c)

Charliechong
Q109. What is a wave called that abruptly changes back and
forth between two voltage levels and remains an equal time
at each level?
a) A sine wave c) a square wave
b) A cosine wave d) a saw tooth wave
My answer: a)
Keywords: abruptly

Charliechong
Sine Wave and Square Wave

Charliechong
Q110. What are three good electrical conductors
a) Copper, gold, mica
b) Gold, silver, wood
c) gold, silver, aluminum
d) copper, aluminum, paper
My answer: c)

Charliechong
Q111. In figure NB-3, which symbol represents an NPN
transistor
a) Symbol 1 c) Symbol 2
b) Symbol 3 d) Symbol 4
My answer: d)
Q112. Which symbol of figure N6-3 represents an PNP
transistor
My answer: a)

Charliechong
Q113. calls must not be broadcast to amateur stations in
general unless:
a) it is to broadcast amateur news
b) It is CQ calls
c) it is to give a weather report
d) there Is a lift on
My answer: a)
CQ* General call; calling any station
黑豹 https://en.wikipedia.org/wiki/CQ_(call)
CQ is a code used by wireless operators, particularly
those communicating in Morse code, (— ·— ·— —
·—), but also by voice operators, to make a general
call (called a CQ call). Transmitting the letters CQ on
a particular radio frequency is an invitation for any
operators listening on that frequency to respond. It is
still widely used in amateur radio.
https://upload.wikimedia.org/wikipedia/commons/8/85/CQ_de_DG2RBH.ogg

Charliechong
Q114. Facsimile transmission using AM is:
a) A3E c) F3E
c) G3C d) A1B
My answer: c)
The actual correct answer is c)
黑豹 https://en.wikipedia.org/wiki/CQ_(call)

Charliechong
1st Symbol Type of modulation of the main carrier
 N Emission of an un-modulated carrier
Emission in which the main carrier is amplitude modulated (including cases where
sub-carriers are angle modulated):
 A i) Double-sideband
 H ii) Single-sideband, full carrier
 R iii) Single-sideband, reduced or variable level carrier
 J iv) Single-sideband, suppressed carrier
 B v) Independent sidebands
 C vi) Vestigial sideband
Emission in which the main carrier is angle-modulated:
 F i) Frequency modulation
 G ii) Phase modulation
 D Emission in which the main carrier is amplitude and angle
 modulated either simultaneously or in a pre-established sequence

Charliechong
Emission of pulses:
 P i) Sequence of un-modulated pulses
 A sequence of pulses:
 K i) modulated in amplitude
 L ii) modulated in width/duration
 M iii) modulated in position/phase
 Q iv) in which the carrier is angle-modulated during the angle period of the pulse
 V v) which is a combination of the foregoing or is produced by other means
 W Cases not covered above, in which an emission consists of the main carrier
modulated, either simultaneously or in a preestablished sequence, in a combination
of two or more of the following modes: amplitude, angle, pulse
 X Cases not otherwise covered

Charliechong
2. Second symbol – Nature of signal(s) modulating the main
carrier Symbol Nature of signal(s) modulating the main
carrier
 0 No modulating signal
 1 A single channel containing quantized or digital information without the use of a
modulating sub-carrier
 2 A single channel containing quantized or digital information with the use of a
modulating sub-carrier
 3 A single channel containing analogue information
 7 Two or more channels containing quantized or digital information
 8 Two or more channels containing analogue information 9 Composite system with
one or more channels containing quantized or digital information, together with one
or more channels containing analogue information

Charliechong
3. Third symbol – Type of information to be transmitted
Symbol Type of information to be transmitted
 N No information transmitted
 A Telegraphy – for aural reception
 B Telegraphy – for automatic reception
 C Facsimile
 D Data transmission, telemetry, telecommand
 E Telephony (including sound broadcasting)
 F Television (video)
 W Combination of the above
Note: The term "Information" does not represent a signal of a constant unvarying
nature, as provided by standard frequency emissions, continuous wave and pulse
radars and etc.

Charliechong
HF/VHF/UHF Range Definitions
黑豹
Category
of product
Frequency
band (MHz)
Frequency
range (MHz)
Maximum
power
level (Watts
PEP)
Class of
emission
HF 28.000 –
29.700
3-30 50 A3E, F1A, F2A,
F3E, J3E and
R3EVHF 50.000 –
54.000
30-300
144.000 –
148.000
UHF 430.000 –
440.000
300-3000

Class of
Transmission
A3E A i) Double-
sideband
information
E Telephony
(including sound
broadcasting)
F1A F i) Frequency
modulation
aural reception
information
E Telephony
(including sound
sideband,
suppressed carrier
information
reduced or
variable level
carrier
Charliechong 黑豹

Charliechong
HF/VHF/UHF Range Definitions
黑豹

Charliechong
Q115. The suffix when riding a motorbike is:
a) /B c) /P
b) /M d) /C
My answer: b)

Charliechong
License Suffixes
 /A clause 17(b) applies so that the ―Alternative address means a fixed postal
address in the UK other than the Main Station Address‖
 /P clause 17(jj) applies so that the ―Temporary Location means a fixed location in
the UK which is not the Main Station Address or an Alternative Address‖
 /M clause 17(x) applies to define Mobile as applying when the Radio Equipment is
―located in the UK in or on any vehicle or conveyance, on person of the Licensee
where the Licensee is a pedestrian or on any Vessel on Inland Waters‖. The latter
is defined in in clauses 17(rr) and(tt).
 /MM clause 17(v) applies to define Maritime Mobile where the ―Radio Equipment
is on any ‗Vessel at Sea‘‖ – the latter being further defined in clauses 17(rr) and
17(ss).
Note that 17(kk) which refers to Tidal Water is no longer formally referenced, but its
inclusion in 17(1) has been known to cause misinterpretation.
黑豹 https://rsgb.org/main/archive/consultation-archive/ofcom-consultations/licence-review-preparation/licence-

Charliechong
Q116. An isolating transformer is used to
a) Ensure that faulty equipment connected to it will blow a ruse In the distribution
board
b) Ensure that no voltage is developed between either output lead and ground
c) Ensure that no voltage is developed between the output leads
d) Step down the mans voltage to a safe value
My answer: d)

Charliechong
An isolation transformer is a transformer used to transfer electrical power
from a source of alternating current (AC) power to some equipment or device while
isolating the powered device from the power source, usually for safety reasons.
Isolation transformers provide galvanic isolation and are used to protect against
electric shock, to suppress electrical noise in sensitive devices, or to transfer power
between two circuits which must not be connected. A transformer sold for isolation is
often built with special insulation between primary and secondary, and is specified to
withstand a high voltage between windings.
Isolation transformers block transmission of the DC component in signals from one
circuit to the other, but allow AC components in signals to pass. Transformers that
have a ratio of 1 to 1 between the primary and secondary windings are often used to
protect secondary circuits and individuals from electrical shocks between energized
conductors and earth ground. Suitably designed isolation transformers block
interference caused by ground loops. Isolation transformers with electrostatic shields
are used for power supplies for sensitive equipment such as computers, medical
devices, or laboratory instruments.

Charliechong
Q117. What device is used to store electrical energy in an
electrostatic field:
a) A battery c) A capacitor
b) A transformer d) An inductor
My answer: d)

Charliechong
Q118. What dies a variable resistor or potentiometer do?
a) Its resistance changes when AC is applied to it
b) its transforms a variable voltage into a constant voltage
c) its resistance changes when its slide or contact Is moved
d) To create an open circuit when there is too much current i n a circuit
My answer: c)

Charliechong
Q119. In figure N6-1. which symbol represents a fixed
resistor.
My answer: b)
Q120. In figure N6-1 which symbol represents a fuse
My answer: a)

Charliechong
Q121. In figure N6-1, which symbol represents a single cell
battery
My answer: d)
Q122. In figure N6-1, which symbol represents an earth
ground:
My answer: d)

Charliechong
Q123. In figure NS-1, which symbol represents an antenna
a) Symbol 2
b) Symbol 3
c) Symbol 6
d) Symbol 7
My answer: d)
Q124. What does a capacitor do:
a) stores energy and opposes a change in current
b) stores energy electrostatically and opposes a change in voltage
c) stores energy electromagnetically and opposes a change in current
d) stores energy electromechanically and opposes a change in voltage
My answer: b)

Charliechong
Q125. In figure N6-2, which symbol represents a single pole,
single throw switch
a) Symbol 1
b) Symbol 2
c) Symbol 3
d) Symbol 4
My answer: a)

Charliechong
Q126. The mains transformer in a transmitter is fitted with
an internal screen. To minimize the possibility of
Introducing mains-borne interference it should be
connected to;
a) the chassis
b) the VFO output
c) the live side of the mains
d) left floating
My answer: a) The correct answer: a)

Charliechong
Q127. The total capacitance of two or more capacitors in
series Is
a) always less than that of the smallest capacitor
b) always greater than that of the largest capacitor
c) found by adding each of the capacitances together
d) found by adding the capacitances together and dividing by their total number
My answer: a) The correct answer: a)

Charliechong
Capacitor Calculation
黑豹 https://keisan.casio.com/exec/system/1258035746

Charliechong
Capacitor in series always less than that of the smallest
capacitor

Charliechong
Inductor Calculation

Charliechong
Calculates the total inductance of two coils in series and
parallel.

Charliechong
Q128. Colpitts. Hartley, Vackar, Clapp-Gouriet are alt types
of
a) power supply c) amplifier
b) oscillator d) modulator
My answer: b)
129. The power supply to a VFO should be:
a) well regulated
b) straight from the smoothing circuit
c) unregulated
d) AC only
My answer: a)

Charliechong
Clapp oscillator
The Clapp oscillator or Gouriet oscillator is an LC electronic oscillator that uses a
particular combination of an inductor and three capacitors to set the oscillator's
frequency. LC oscillators use a transistor (or vacuum tube or other gain element) and
a positive feedback network. The oscillator has good frequency stability.
Clapp oscillator (direct-current biasing
network not shown)

Charliechong
Q130. The block diagram below is of a typical 144 MH
transmitter using multipliers. The box marked X is:
a) a doubler c) a triplet
b) a quadrupler d) a buffer
My answer: a)
黑豹 http://electricalacademia.com/electronics/radio-transmitter-and-receiver-working-block-diagram/
Many CW transmitters use frequency multipliers
to increase the frequency produced by the basic
oscillator. These circuits multiply the carrier wave
by two (doubler) or three (tripler). These circuits
operate on the principle of harmonics in the
fundamental carrier frequency created by the
oscillator.
x + x2 = x3
(triplet)

Charliechong
Q131. If the carrier generated by the signal in the above
question Is to be amplitude modulated, modulation should
be applied at:
a) A c) B
b) C d) D
My answer: d)
Q132. When calling a station, it is good practice to:
a) put your callsign first
b) use your callsign only
c) put the callsign of the station being called first
d) use the callsign of the other station only
My answer: c)

Charliechong
Transceiver Block Diagrams
AM Transmitter
黑豹 https://www.petervis.com/Education/radio-transmitter-block-diagram/radio-transmitter-block-diagram.html

Charliechong
Radio Transmitter Block Diagram
This block diagram of a radio transmitter in a communication system is very simple
and basic. It is generalised for AM and FM types of modulation, and consists of four
subsystems. Communication is the transfer of meaningful information from one
location to another.
 We start with the conversion of sound waves in the air into electrical energy. A
transducer, which is usually a microphone, does this job very well.
 The carrier wave generator is an oscillator, which produces pure un-modulated sine
waves in the radio frequency range. It usually consists of a tuned oscillator circuit
that produces a carrier wave of a specific frequency.
 The signal from the carrier wave generator, and transducer, feeds a modulator,
which encodes the carrier signal with the information we wish to send.
There are two types of modulation methods; in AM, the amplitude of the carrier
modulates, whilst in FM the frequency of the carrier modulates.
 The transmitter block is usually responsible for generating electromagnetic waves
that travel through the air.

Charliechong
AM/FM Transmitter
A transducer, which is
usually a microphone
The carrier wave generator is an
oscillator, which produces pure un-
modulated sine waves in the radio
frequency range.
 The signal from the carrier wave generator,
and transducer, feeds a modulator, which
encodes the carrier signal with the
information we wish to send.
 The transmitter block is usually
responsible for generating
electromagnetic waves that
travel through the air.

Charliechong
Simple Radio Receiver Block Diagram
 Point A has wide
range of modulated
radio frequency
signals.
 Point B has a
narrow range of
modulated
frequency signals.
 Point C has small amplitude
audio frequency signal.
 Point D has a large
amplitude audio
frequency signal.

Charliechong
This block diagram is for a simple radio receiver such as a crystal radio, and
consequently it does not have an oscillator or mixer stage.
 Point A has wide range of modulated radio frequency signals.
 Point B has a narrow range of modulated frequency signals.
 Point C has small amplitude audio frequency signal.
 Point D has a large amplitude audio frequency signal.
The detector stage, also known as the demodulator, is where the carrier frequency
and the audio signals separate. It strips the carrier away to leave only the audio signal.
In a crystal radio, a germanium diode usually performs this process.
The tuned circuit usually consists of a ferrite rod with a coil wound around it. A variable
tuning capacitor usually connects to the coil in parallel. The coilinductance (L) and the
tuning capacitance (C) form an LC circuit, which determines the resonance
frequency when selecting a particular frequency.

Charliechong
Summary
The antenna generates an electrical signal from electromagnetic waves.
The detector/demodulator creates a non-zero average signal.
Headphones/loudspeakers convert electrical signals into sound.
Tuned circuit selects the required radio station.
RF Filter removes the high frequency component leaving the audio signal for
amplification.

Charliechong 黑豹 https://www.petervis.com/Education/radio-transmitter-block-diagram/radio-transmitter-block-diagram.html
FM Radio Receiver Block Diagram
FM detector, also
known as
discriminator

Charliechong
FM Radio Block Diagram
This super-heterodyne FM radio block diagram shows all the main stages of a modern
radio. The first three stages are very similar to an AM radio block diagram; however,
the main difference is in the limiter and FM detector stages, which are crucial to FM
reception. These stages are responsible for decoding the frequency-modulated signal.
In order to understand them, we need to consider the encoding process because the
decoding is simply the reverse.

Charliechong
Limiter Stage
The limiter stage is a very simple IF amplifier that keeps the amplitude of the FM
signal to a constant level. It has a built-in gain control circuitry so that the amplitude of
the signal remains precisely the same. This is because the FM carrier is just as
vulnerable to have its amplitude corrupted as AM is, however, since FM does not store
information in the amplitude of the carrier, we can correct any corruptions easily and
maintain the amplitude to a constant value.

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FM Detector Stage
In FM encoding, the amplitude of the carrier wave remains constant, and it is the
variation in frequency where information is stored. Specifically, variation in frequency
is proportional to the amplitude of the encoding signal. In many ways, you can think of
this as amplitude to frequency conversion. When the encoding signal is in positive
phase, the carrier frequency is at maximum, however when it is in negative phase, the
carrier frequency is at minimum. Variation in frequency is proportional to the amplitude
of the encoding signal. This way we can represent the level of amplitude in terms of
frequency.
In a radio receiver, the FM detector, also known as discriminator, does the opposite
because it has to decode the encoded signal. Therefore, the FM detector stage
converts variations in frequency to variations in amplitude to recover the original signal.
Hence, this is very much a frequency to amplitude converter. In electronics, many IC
packages can convert frequency to voltage. This is where the voltage is proportional
to frequency.

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Radio Designs
In practice, many radios that can receive FM and AM have a shared IF stage, and AF
stage. Usually a radio that has FM reception will have a special FM tuner encased in
metal shielding. Usually this part contains the oscillator, mixer, and RF stages. If you
look at the construction of the Zenith Transoceanic, then it might give more insight.

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Radio Transmitter and Receiver | Working | Block Diagram
Figure 1. A simple crystal
radio can receive AM radio
signals and convert them to
sound.
Also known as an inductor-capacitor circuit, an LC circuit, a resonator circuit or a tuned circuit, a tank
circuit is a simple electrical circuit that uses magnetic resonance to store an electrical charge or
produce an electromagnetic frequency. If you've ever wondered how your radio picks up single
frequencies when you turn the dial -- instead of playing all the radio frequencies in the air at the
same time -- the answer is a tank circuit.

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Tank Circuit
The tank circuit consists of an inductor and a variable capacitor connected in parallel.
As we know that an inductor and capacitor connected in parallel will have a resonant
frequency.
By using a variable capacitor, you are able to vary the tank circuit resonant frequency
until it matches the frequency of the desired station.
For example, if we wish to tune in station 1, the capacitor is varied until the resonant
frequency of the tank circuit is equal to 920 kHz. Receiving a frequency of 920 kHz will
cause the greatest voltage drop across the tank circuit.
The other frequencies (1040 station 3, and 1460 station 2) will not produce a large
voltage drop across the tank circuit.
黑豹 https://www.techwalla.com/articles/what-is-a-tank-circuit

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What Is It?
A tank circuit consists of a capacitor connected to a coil, an inductor, by wires. A
capacitor is simply two conductive plates separated by a non-conductive material such
as wax paper. When the capacitor receives an electric charge, positive and negative
charges accumulate on opposite ends of the non-conductive surface. Because
opposite charges attract but cannot pass through the non-conductive surface, they
move through the wires to the inductor coil, electromagnetically charging the inductor.

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How It Works
The resonance in a tank circuit is created by the movement between the capacitor and
the inductor, the same movement Savary noticed in the Leyden Jar. As electrical
charge moves from the capacitor to the coil, the capacitor loses electromagnetic
energy and the inductor becomes electromagnetically charged. Once the inductor is
more charged than the capacitor, however, the electromagnetic cloud around the coil
begins to dissipate and energy flows back through the wires to the capacitor. The
process then begins again and repeats over and over until all of the original energy is
lost to resistance in the circuit.

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Uses of Tank Circuits
The back-and-forth of electrical energy between the capacitor and inductor emits an
electromagnetic frequency that is very useful in telecommunications technology. Often
used in tuning radio transmitters and receivers, tank circuits can be charged to
produce a specific frequency. When you turn a radio to a specific station, you're really
changing the charge on a tank circuit so that it resonates at that frequency. That
specific resonance is used to filter out other frequencies and only play the station you
selected. The same technology is used in all sorts of communications equipment, from
radio towers to walkie-talkies.

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Tank Circuit
黑豹 https://www.youtube.com/embed/7rqFpEZtYUU

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Detector
The detector rectifies the radio signal to a pulsing dc signal. The filter capacitor
smoothers the high frequency of the audio portion of the radio signal.
The detector diode and filter capacitor are necessary to change the broadcast
frequency and audio signal to a reproducible sound at the headphones.
The description above may sound simple, and that is because this is the simple
operation of a radio receiver. The radio described is known as a crystal radio receiver.
When constructed properly in the lab, you can actually receive and hear a few stations.
The performance of this radio, however, is extremely poor by today‘s standards.
Today‘s radios and televisions operate from the same principles just described, but
they are a significant refinement of the crystal set.
Take special note of the fact that there is no battery or other conventional power
supply for this radio. First, we will discuss the power source for this radio.

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Amplitude Modulation AM Demodulation- Diode Envelope
Detector
黑豹 https://www.youtube.com/embed/e_gTCU2fnD8

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Amplitude Modulation and Frequency Modulation
黑豹 https://www.youtube.com/embed/e_gTCU2fnD8

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Radio Waves
A radio wave is an electromagnetic radiation produced from current alternating
through an antenna.
A transmitting antenna is surrounded by electromagnetic radiation. In the study of
electromagnetism, we learned that a conductor carrying an electric current is
surrounded by a magnetic field. In a magnetic field created by an alternating current,
the field expands, collapses, and changes polarity in step with the frequency.
An oscillator can produce high-frequency alternating currents that produce a radio
wave when connected to an antenna. In general, the radio wave is an electrostatic
radiation of energy produced by an oscillator circuit. The electrostatic field is
perpendicular to the electromagnetic field. Both travel away from the antenna. As a
result, a radio wave is made up of electromagnetic and electrostatic fields. See Figure
2.
The direction these waves radiate, in respect to the earth, is called polarization.

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Figure 2. The relationship between electrostatic and electromagnetic waves. They are
perpendicular to each other and both are perpendicular to the direction of travel.
For dipole antenna, the
electrostatic components
polarized parallel in the same
plane with the earth.
For dipole antenna, the
electromagnetic components
polarized vertical
perpendicular with the earth.

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In Figure 3 the waves are radiated from a vertical antenna. Note that the electrostatic,
or E waves, are in the same plane as the antenna, yet perpendicular to the direction of
travel. The vertically polarized waves are perpendicular to the surface of the earth. In
Figure 4, the wave is radiated from a horizontal antenna. It is still perpendicular to the
direction of travel but is parallel to the surface of the earth.
Generally speaking, the antenna that receives these waves should be positioned in
the same way as the transmitting antenna. At high frequencies, the polarization
changes slightly as the wave moves. Does all this mean the transmitting antenna
radiates two waves? The answer is found in the fact that without one, there cannot be
the other.
A moving electrostatic field produces a moving electromagnetic field, and likewise, a
moving electromagnetic field produces a moving electrostatic field. These conditions
exist whether an actual conductor is present or not.
The radiated waves from an antenna can be divided into two groups. These are
ground waves and sky waves.

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Figure 3. A vertical antenna radiates a vertically polarized wave.

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Figure 4. A horizontal antenna radiates a horizontally polarized wave.

Charliechong 黑豹 http://electricalacademia.com/electronics/radio-transmitter-and-receiver-working-block-diagram/
Ground waves
A ground wave follows the surface of the earth to the radio receiver. The ground wave
has three parts:
 The surface wave.
 The direct wave, which follows a direct path from the transmitter to the receiver.
 The ground-reflected a wave, which strikes the ground and is then reflected the
receiver.
The last two waves are combined and called a space wave. The waves that make up
the space wave may or may not arrive at the receiver in proper order. They may join
together or cancel each other, depending on distances traveled by each wave.
Broadcast stations depend on the surface wave for reliable communications. As the
surface wave travels along the surface of the earth, it induces currents in the earth‘s
surface. These currents use up the energy contained in the wave. The wave becomes
weaker as the distance it travels increases.
An interesting side note is that salt water conducts surface waves about 5000 times
better than the land. Overseas communication is very reliable when transmitters are
near the coastline. These stations use high power and operate at lower frequencies
than the normal broadcast band.

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Sky Waves
The second type of radiated wave is a sky wave. Sky waves use the ionized layer of
the earth‘s atmosphere for transmission. This layer is called the ionosphere. It is
located from 40 to 300 miles above the earth‘s surface. It is believed to consist of
large numbers of positive and negative ions.
As the sky wave radiates, it strikes the ionosphere. Some of the waves can be
absorbed into the ionosphere. But some will bounce off the layer and be sent back to
the earth‘s surface. See Figure 5

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Figure 5. Sky waves bounce off the ionosphere and move back to the earth‘s surface.

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Radio Transmitter Working Principle
Any oscillator will produce radio frequency waves. When the oscillator is connected to
an antenna system, it sends energy into the atmosphere. Amplification will increase
the amplitude of the oscillator wave so that it will drive a final power amplifier.

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Continuous Wave Transmitter
A block diagram of a simple continuous wave (CW) transmitter is shown in Figure 6.
The first block is the conventional crystal oscillator and then the final power amplifier. A
power supply is provided for the oscillator and the final power amplifier.
Following the action in Figure 6, the oscillator creates an ac sine wave at the desired
frequency. This signal is called the carrier wave. The carrier wave is then amplified by
the radio frequency (RF) power amplifier to the desired output wattage.
A power supply is required to provide the voltages and current needed to operate the
oscillator and the RF power amplifier. The output is then fed to an antenna. From there,
the energy is sent into the air as electromagnetic waves.
Notice that a CW transmitter sends energy that has no audio or video message. The
CW transmitter has only two states, on or off. How can this type of transmitter be
useful? By adding a switch, the transmitter can be turned on and off following a code.
For example, such a transmitter could be used to send Morse code messages, Figure
7. Figure 8 lists the character set for sending Morse code messages.

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Figure 6. A block diagram representing various stages of a basic continuous wave
radio transmitter.

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Figure 7. Continuous wave transmitter with a telegraph key. Note break in RF
waveform indicating an open switch at that point.

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Figure 8. The character set for Morse code.

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The basic switched, or keyed, CW transmitter can be improved by placing a buffer
amplifier between the oscillator and the RF amplifier.
The buffer amplifier isolates the oscillator from the RF amplifier and keeps it from
shifting off of the desired frequency. It also provides some amplification to the carrier
wave.
Many CW transmitters use frequency multipliers to increase the frequency produced
by the basic oscillator. These circuits multiply the carrier wave by two (doubler) or
three (tripler). These circuits operate on the principle of harmonics in the fundamental
carrier frequency created by the oscillator.
A fundamental frequency is a basic frequency produced by the oscillator. A harmonic
frequency is a multiple of the fundamental frequency.

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Microphones
How is a sound wave converted to an electrical wave? Your vocal cords send
vibrations in the air. These waves move out to all persons within hearing range.
A microphone will convert these sound waves into electrical audio waves of the same
frequency and relative amplitude. Microphones are sometimes called transducers.
This is because they transform one form of energy (vibrating air, or mechanical) to
electrical energy. Figure 9 shows a microphone built into a video camera.

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Figure 9. This video camera is equipped with a stereo microphone.
(Sony Electronics Corp.)

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Carbon microphone
A diagram of a carbon microphone is shown in Figure 10. Granules of carbon are
packed in a small container. Electrical connections are made to each side.
A transformer and a small battery are joined in series with the carbon. A diaphragm is
attached to one side of the container. This diaphragm is sometimes called a button.
Sound waves strike the diaphragm (button) and cause the carbon granules to be
compressed or pushed together. This varies the resistance of the carbon.
Varying resistance causes a varying current to flow through the carbon button and the
transformer primary. The output is a current that varies at the same frequency as the
sound waves acting on the diaphragm.
The carbon microphone is a very sensitive device. It has a frequency response up to
about 4000 Hz. This is useful for voice communication, but not for the reproduction of
music. It provides a good response for its intended frequencies. A carbon microphone
is non-directional, which means it will pick up sound from all directions.

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Figure 10. In a carbon microphone, sound waves change the resistance of the circuit.

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Crystal microphone
The second type of microphone uses the piezoelectric effect of certain crystals. It is
called a crystal microphone. When sound waves strike a diaphragm, mechanical
pressure is transferred to the crystal. The flexing or bending of the crystal creates a
small voltage between its surfaces. This voltage is the same frequency and relative
amplitude as the sound wave, Figure 11.
Crystal microphones have a frequency response up to 10,000 Hz. They are sensitive
to shock and vibration. They should be handled with care.

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Figure 11. Mechanical pressure is used to produce electrical energy. The crystal
microphone takes advantage of the piezoelectric effect.

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Dynamic microphone
A dynamic microphone, or moving coil microphone, is sketched in Figure 12. As sound
waves strike the diaphragm, they cause the voice coil to move in and out. The voice
coil is surrounded by a fixed magnetic field.
When the coil moves, a voltage is induced in the coil (Faraday‘s discovery). This
induced voltage causes current to flow at a frequency and amplitude similar to the
sound wave causing the motion. It has a frequency response up to 9000 Hz. It is
directional and requires no outside voltage for operation.

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Figure 12. Dynamic microphone. Electrical audio waves are produced by a coil
moving in a magnetic field.

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Condenser microphone
A condenser microphone operates on the principle of capacitance. It is similar in
construction to a capacitor, consisting of two plates separated by air.
One plate is rigid while the other is moveable. As sound waves strike the movable
plate, the distance between the two plates will vary, varying the capacitance of the
microphone.
The varying capacitance of the microphone causes a reproduction of the audio signal
similar in frequency and amplitude. The condenser microphone is very sensitive when
compared to other types of microphones.

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Condenser Microphone

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Velocity Microphone
A high-quality microphone, called a velocity microphone, is made by suspending a
corrugated ribbon of metal in a magnetic field.
Sound waves directly striking the ribbon cause the ribbon to vibrate. As the ribbon cuts
the magnetic field, a voltage is induced.
Proper connections at the ends of the ribbon bring the voltage out to terminals. This
voltage varies according to the frequency and amplitude of the incoming sound waves.
The velocity microphone is a somewhat delicate microphone with a response above
12,000 Hz. When using this microphone, the speaker must speak across its face or
stand about 18 inches away. Otherwise, a ―booming‖ effect is created.

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Velocity Microphone

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Modulation
When you turn on the radio or TV, you expect to hear music and voices you
understand. The signals of the CW transmitter mean nothing to the average person.
To make an understandable message, an audio wave is combined, or superimposed,
on a carrier wave. See Figure 13.
The process of combining an audio wave with a carrier wave is called modulation.
Sound waves are converted by microphones into electrical waves, amplified, and then
combined with the CW radio wave. Amplitude modulation occurs when the amplitude
of the CW radio wave is made to vary at an audio frequency rate. Amplitude
modulation is referred to as AM.
In a second method, the radio wave frequency is made to vary at an audio frequency
rate. This is called frequency modulation or FM.
Part A shows the modulation of the amplitude of a carrier wave. Part B shows the
modulation of the frequency of a carrier wave

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Figure 13. Carrier waves and resulting modulated waves. A–Amplitude modulation, or
AM. B–Frequency modulation, or FM.

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Q133. What is the advantage in using the International
Telecommunication Union (ITU) phonetic alphabet when
identifying your station?
a) the words are internationally recognized substitutes for letters
b) there is no advantage
c) the words have been chosen to be easily pronounced by Asian cultures
d) k preserves traditions begun in the early days of Amateur Radio
My answer: a)

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Question from 134 to 136 relates to this diagram below:

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Q134. In this diagram the item U corresponds to the
a) boom c) driven element
b) reflector d) director
My answer: a)
Q135. In this diagram the item V corresponds to the
My answer: b)
Q136. In this diagram the item X corresponds to the
My answer: d) The correct answer: d)

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Q137. How does a spectrum analyzer differ from a
conventional time domain oscilloscope
a) A spectrum analyzer measures ionospheric reflection; an oscilloscopes displays
electrical signals
b) A spectrum analyse displays signals in the time domain; an oscilloscope displays
signals in the frequency domain
c) A spectrum analyzer displays signals in the frequency domain; an oscilloscope
displays signals in the time domain
d) A spectrum analyzer displays radio frequencies; an oscilloscope displays audio
frequencies
My answer: c)

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Q138. What instrument can be used to determine the
horizontal radiation pattern or an antenna?
a) a field-strength meter
b) a grid-dip meter
c) an oscilloscope
d) a signal tracer & an audio amplifier
My answer: d)
Q139. What can a logic probe indicate about a digital logic
circuit?
a) a short-circuit fault
b) an open-circuit fault
c) the resistance between logic modules
d) the high & low logic states
My answer: d) The correct answer: d)
In telecommunications, a field
strength meter is an instrument
that measures the electric field
strength emanating from a
transmitter.

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logic probe- A logic probe is a hand-held test probe used for analyzing and
troubleshooting the logical states (boolean 0 or 1) of a digital circuit.

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Q140. What does a frequency counter do?
a) It makes frequency measurements
b) It produces a reference frequency
b) It measures FM transmitter deviation
d) It generates broadband white noise
My answer: a)
Q141. A mains operated DC power supply
a) Converts DC from the mains Into AC of the same voltage
b) Converts energy from the mains into DC for operating electronic equipment
c) Is a diode-capacitor device lot measuring mains power
d) Is a diode-choked device for measuring inductance Power
My answer: b)
A frequency counter is an electronic instrument, or
component of one, that is used for measuring frequency.
Frequency counters usually measure the number of cycles
of oscillation, or pulses per second in a periodic electronic
signal. Such an instrument is sometimes referred to as a
cymometer, particularly one of Chinese manufacture.

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Q142. A low pass filer will:
a) suppress sub-harmonics
b) Reduce harmonic
c) always eliminate interference
d) improve harmonic radiation
My answer: d)
Q143. An antenna Balun is:
a) a balance to unbalance transformer
b) a mains transformer
c) a single winding inductor
d) a semiconductor device
My answer: a)

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Q144. What is simplex operation?
a) transmitting and receiving on the same frequency
b) transmitting and receiving over a wide area
c) transmitting on one frequency and receiving on another
d) transmitting one-way communications
My answer: a)

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Q145. The main purpose of a repeater is:
a) to ·improve communication between mobile stations
b) to provide a convenient frequency for local nets
c) to aid DX working during lift conditions
d) to aid propagation studies
My answer: a)
Q146. The standard tone use for amateur repeaters in
Malaysia is
a) 203.5 MHz c) 103.5 Hz
b) 203.5 Hz d) 250.3 Hz
My answer: a)

Radio amateur examination q51 q150

Radio amateur examination q51 q150

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