Radio amateur examination q01 q50

4x4 Adventures
The Essentials:
MALAYSIAN
RADIO AMATUER EXAMINATION
SAMPLE QUESTIONS with Answers.
Q1~Q50
26th March 2019
Charliechong 黑豹 https://sems.skmm.gov.my/sems/

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
Q1. Amateur radio station means:
a) a station for financial gain & operated by a radio amateur.
b) a station for a service of self-tuition, intercommunication and technical investigation
that is operated by an amateur.
c) a station that uses radio waves and is erected by an amateur.
d) a station of self tuition that Is erected for use from an aircraft or a public vehicle.
My answer: b).
The correct answer is b).
黑豹 https://www.facebook.com/puma4x4

Charliechong
Q2. identify four purposes for the amateur service
i) to protect historical radio data
ii) to help the public understand radio history
iii) to help foreign countries Improve communication
iv) to help improve technical skills
v) to encourage visits from foreign hams
vi) to modernize radio schematic drawings
vii) to Increase the pool of electrical drafting people
viii) to Increase the number of trained radio operators
ix) to Increase the number of electronics experimenters
x) to Improve International goodwill
a) I, II, iii & iv c) ii, lv, ix & x
b) Ill, v, vii & lx d) iv, vii, ix & x
My answer: d)
The correct answer is d).

Charliechong 黑豹 https://www.facebook.com/puma4x4
CFR Title 47: Telecommunication PART 97—AMATEUR RADIO SERVICE Contents Subpart A-General
Provisions §97.1 Basis and purpose. §97.3 Definitions. §97.5 Station license required. §97.7 Control operator
required. §97.9 Operator license grant. §97.11 Stations aboard ships or aircraft. §97.13 Restrictions on station
location. §97.15 Station antenna structures. §97.17 Application for new license grant. §97.19 Application for a
vanity call sign. §97.21 Application for a modified or renewed license grant. §97.23 Mailing address. §97.25
License term. §97.27 FCC modification of station license grant. §97.29 Replacement license grant document.
§97.31 Cancellation on account of the licensee's death.
Subpart A—General Provisions §97.1 Basis and purpose. The rules and regulations in
this part are designed to provide an amateur radio service having a fundamental
purpose as expressed in the following principles:
(a) Recognition and enhancement of the value of the amateur service to the public as
a voluntary noncommercial communication service, particularly with respect to
providing emergency communications.
(b) Continuation and extension of the amateur's proven ability to contribute to the
advancement of the radio art
(c) Encouragement and improvement of the amateur service through rules which
provide for advancing skills in both the communication and technical phases of the
art.
(d) Expansion of the existing reservoir within the amateur radio service of trained
operators, technicians, and electronics experts.
(e) Continuation and extension of the amateur's unique ability to enhance international
goodwill.

Charliechong 黑豹 http://www.arrl.org/files/file/Regulatory/March%208,%202018.pdf
CFR Title 47: Telecommunication PART 97—AMATEUR RADIO SERVICE Contents Subpart A-General
Provisions §97.1 Basis and purpose. §97.3 Definitions. §97.5 Station license required. §97.7 Control operator
required. §97.9 Operator license grant. §97.11 Stations aboard ships or aircraft. §97.13 Restrictions on station
location. §97.15 Station antenna structures. §97.17 Application for new license grant. §97.19 Application for a
vanity call sign. §97.21 Application for a modified or renewed license grant. §97.23 Mailing address. §97.25
License term. §97.27 FCC modification of station license grant. §97.29 Replacement license grant document.
§97.31 Cancellation on account of the licensee's death.
Subpart A—General Provisions §97.1 Basis and purpose. The rules and regulations in
this part are designed to provide an amateur radio service having a fundamental
purpose as expressed in the following principles:
(a) Recognition and enhancement of the value of the amateur service to the public as
a voluntary noncommercial communication service, particularly with respect to
providing emergency communications.
(b) Continuation and extension of the amateur's proven ability to contribute to the
advancement of the radio art
(c) Encouragement and improvement of the amateur service through rules which
provide for advancing skills in both the communication and technical phases of the
art. (iv, ix?)
(d) Expansion of the existing reservoir within the amateur radio service of trained
operators, technicians, and electronics experts. (viii)
(e) Continuation and extension of the amateur's unique ability to enhance international
goodwill. (x)

Charliechong
Q2. identify four purposes for the amateur service
i) to protect historical radio data
ii) to help the public understand radio history
iii) to help foreign countries Improve communication
iv) to help improve technical skills
v) to encourage visits from foreign hams
vi) to modernize radio schematic drawings
vii) to Increase the pool of electrical drafting people
viii) to Increase the number of trained radio operators
ix) to Increase the number of electronics experimenters
x) to Improve International goodwill
a) I, II, iii & iv c) ii, lv, ix & x
b) Ill, v, vii & lx d) iv, vii, ix & x
My answer: d)
黑豹
 to Increase the pool of electrical drafting
people
 to Increase the number of electronics
experimenters
https://www.facebook.com/puma4x4

Charliechong
3. The renewal fee for the class A and B licenses are:
a) RM12.00 & RM24.00
b) RM36.00 & RM24.00
c) RM24.00 & RM36.00
d) RM48.00 & RM60.00
My answer: b
4. A class B licensee may operate in the following bands:
a) 144 - 148MHz c) 50 MHz and above
b) 144 - 146 MHz d) 50 MHz and below
My answer: b

Charliechong
GUIDELINE FOR AMATEUR RADIO SERVICES IN MALAYSIA
Second Edition. Pg. 15/76
The fees for the ASAA are tabled as below:

Charliechong
黑豹
Appendix 1:
Amateur
Frequency
Band, Power
and Classes
of Emission
Class A
privilege

Charliechong
黑豹
Appendix 1:
Amateur
Frequency
Band, Power
and Classes
of Emission
Class B
privilege

Charliechong
3. The renewal fee for the class A and B licenses are:
a) RM12.00 & RM24.00
b) RM36.00 & RM24.00
c) RM24.00 & RM36.00
d) RM48.00 & RM60.00
My answer: b
4. A class B licensee may operate in the following bands:
a) 144 - 148MHz c) 50 MHz and above
b) 144 - 146 MHz d) 50 MHz and below
My answer: a)
The correct answer is a).

Charliechong
To Remember!

Charliechong
Q5. The maximum power output permitted from a class B
grade amateur operators station is :
a) 100 watt mean power to 300 watt PEP
b) 120 watt mean power to 400 watt PEP
c) 10 watt mean power to 30 watt PEP
d) 1 000 watt mean power to 2000 watt PEP
My answer: c).
The correct answer is c).
The actual answer is none.

Charliechong
Watt (PEP)
Peak envelope power (PEP) is the highest envelope power supplied to the antenna
transmission line by a transmitter during any full undistorted RF cycle or series of
complete radio frequency cycles. PEP is normally considered the occasional or
continuously repeating crest of the modulation envelope under normal operating
conditions. The United States Federal Communications Commission uses PEP to set
maximum power standards for amateur radio transmitters.
https://en.wikipedia.org/wiki/Peak_envelope_power

Charliechong
Q6. The voltage across a resistor carrying current can be
calculated using the formula:
a) E = I + R (voltage equals current plus resistance)
b) E = I - R (voltage equals current minus resistance)
c) E =I x R (voltage equals current times resistance)
d) E =I/ R (voltage equals current divided by resistance)
My answer: c).
The actual answer is none.

Charliechong
Q7. 2 and are connected across a 40 volt battery. if resistor
is 1000 ohms, the total battery current is:
a) 40 ampere c) 80 ampere
b) 40 milliampere d) 80 milliampere
The total resistance is 1/Rtotal = 1/R1+ 1/R2 + ……… = 500Ω
V= IR
I = 40/500 = 0.08A = 80 milliampere#
My answer: d).

Charliechong
Parallel Resistor Equation
1/Rtotal = 1/R1+ 1/R2 + ………
http://tayyabsiddiqui19.blogspot.com/2012/12/resistors-in-parallel.html

Charliechong
Q8. If a 100 Ohm resistor is connected to 200 volts, what is
the current through the resistor:
a) 1 ampere c) 300 amperes
b) 2 amperes d) 20000 amperes
V=IR
I = 200/100 = 2 Ampere#
My answer: b).
黑豹 https://sems.skmm.gov.my/sems/

Charliechong
Q9. Silicon in its pure form Is:
a) A conductor c) A superconductor
b) An insulator d) A semiconductor
My answer: b).
Q10. A licensee must be able to:
a) use two different languages
b) verify that his transmissions are within the authorized frequency bands
c) read Morse at 20 v.pm
d) Write
My answer: c).
黑豹 https://sems.skmm.gov.my/sems/

Charliechong
The tests will not include any punctuation or other symbols except for full stops,
commas, oblique strokes, question marks and error symbols. The foregoing
particulars are summarized in the following:

Charliechong
A licensee…….
A licensee is not Class “A‟‟ licensee.
Neither is a Class “A” licensee need to read Morse code at 20 v.p.m.

Charliechong
11. The first odd harmonic of 144.69 MHz:
a) 4823 MHz c) 289.38 MHz
b) 434.07 MHz d) 723.45 MHz
My answer: b).

Charliechong
Harmonic
Harmonic of a wave is a component frequency of the signal, which is the integer
multiple of the fundamental frequency. If the fundamental frequency is f, the harmonics
have frequencies f, 2f, 3f, 4f, etc., Even harmonics are 2f, 4f, 6f, and Odd harmonics
are f, 3f, 5f.

Charliechong
Standing Waves and Harmonics
黑豹 https://youtu.be/0Rfushlee0U

Charliechong
Standing Waves and Harmonics
黑豹 https://youtu.be/vkh8Jfmm3hk

Charliechong
Harmonic
A harmonic is a signal or wave whose frequency is an integral (whole-number) multiple of the frequency of
some reference signal or wave. The term can also refer to the ratio of the frequency of such a signal or wave to
the frequency of the reference signal or wave.
Let f represent the main, or fundamental, frequency of an alternating current ( AC ) signal, electromagnetic field ,
or sound wave. This frequency, usually expressed in hertz , is the frequency at which most of the energy is
contained, or at which the signal is defined to occur. If the signal is displayed on an oscilloscope, the waveform
will appear to repeat at a rate corresponding to f Hz.
For a signal whose fundamental frequency is f , the second harmonic has a frequency 2 f , the third harmonic
has a frequency of 3 f , and so on. Let w represent the wavelength of the signal or wave in a specified medium.
The second harmonic has a wavelength of w /2, the third harmonic has a wavelength of w /3, and so on.
Signals occurring at frequencies of 2 f , 4 f , 6 f , etc. are called even harmonics; the signals at frequencies of 3
f , 5 f , 7 f , etc. are called odd harmonics. A signal can, in theory, have infinitely many harmonics.
Nearly all signals contain energy at harmonic frequencies, in addition to the energy at the fundamental
frequency. If all the energy in a signal is contained at the fundamental frequency, then that signal is a perfect
sine wave. If the signal is not a perfect sine wave, then some energy is contained in the harmonics. Some
waveforms contain large amounts of energy at harmonic frequencies. Examples are square waves, sawtooth
waves, and triangular waves.
In wireless communications and broadcasting, transmitters are designed so they emit a minimum of energy at
harmonic frequencies. Normally, a wireless device is intended for use at only one frequency. Signal output at
harmonic frequencies can cause interference to other communications or broadcasting. For example, a
broadcast signal at 90.5 MHz (in the standard FM band) would have a second harmonic at 181 MHz, a third
harmonic at 271.5 MHz, a fourth harmonic at 362 MHz, and so on. Some or all of these harmonic signals could,
if strong, disrupt activities in other wireless services.

Charliechong
Q12. Single sideband, suppressed carrier transmission is
dented by.
a) A3E
b) J3E
c) F3E
d) R3E
My answer: d).

Charliechong
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
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)

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
the use of a modulating sub-carrier
F3E A single channel containing analogue
information
E Telephony
(including sound
broadcasting)J3E iv) Single-
sideband,
suppressed carrier
A single channel containing analogue
information
R3E iii) Single-sideband,
reduced or
variable level
carrier
Charliechong 黑豹
Aural- relating to the ear or the sense of hearing.

Charliechong
Q13. The coaxial cable from an SWR meter to an antenna
develops a fault so that no power reaches the antenna. The
SWR meter will read:
a) zero c) 1:1
b) high d) very low
My answer: a).

Charliechong
The Correct Answer
 Incident wave (blue) is fully reflected (red wave) out of phase at short-circuited
end of transmission line, creating a net voltage (black) standing wave. Γ = −1,
SWR = α.
 Incident wave (blue) is fully reflected (red wave) out of phase at open-circuited
end of transmission line, creating a net voltage (black) standing wave. Γ = −1,
SWR = α.
VSWR = Vmax / Vmin = (1+│Γ│) / (1-│Γ│) -
At Fault
Open-circuit
VSWR = Vmax / Vmin = (1+│1│) / (1-│1│) = 2/0 = α.
Short-circuit
VSWR = Vmax / Vmin = (1+│1│) / (1-│1│) = 2/0 = α.

Charliechong
SWR/VSWR Standing Wave Ratio
In radio engineering and telecommunications, standing wave ratio (SWR) is a
measure of impedance matching of loads to the characteristic impedance of a
transmission line or waveguide. Impedance mismatches result in standing waves
along the transmission line, and SWR is defined as the ratio of the partial standing
wave's amplitude at an antinode (maximum) to the amplitude at a node (minimum)
along the line.
The SWR is usually thought of in terms of the maximum and minimum AC voltages
along the transmission line, thus called the voltage standing wave ratio or VSWR
(sometimes pronounced "vizwar"[1][2]). For example, the VSWR value 1.2:1 denotes
an AC voltage due to standing waves along the transmission line reaching a peak
value 1.2 times that of the minimum AC voltage along that line. The SWR can as well
be defined as the ratio of the maximum amplitude to minimum amplitude of the
transmission line's currents, electric field strength, or the magnetic field strength.
Neglecting transmission line loss, these ratios are identical.
The power standing wave ratio (PSWR) is defined as the square of the VSWR,[3]
however, this deprecated terminology has no physical relation to actual powers
involved in transmission.
黑豹 https://en.wikipedia.org/wiki/Standing_wave_ratio

Charliechong
Standing Wave Ratio
Incident wave (blue) is fully reflected (red wave) out of phase at short-circuited end of
transmission line, creating a net voltage (black) standing wave. Γ = −1, SWR = α.
The reflection coefficient
Γ = -1 complete negative reflection, when the line is short-circuited,
Γ = 0 no reflection, when the line is perfectly matched,
Γ = +1complete positive reflection, when the line is open-circuited.
VSWR = Vmax / Vmin = (1+│Γ│) / (1-│Γ│)

Charliechong
CB Tuning with Amazon SWR Meter
黑豹 https://youtu.be/X5M_cD1vWRo

Charliechong
What is VSWR: Voltage Standing Wave Ratio | Electronics
Notes
黑豹 https://youtu.be/BSa051lWB_c

Charliechong
#208: Visualizing RF Standing Waves on Transmission
Lines
黑豹 https://youtu.be/M1PgCOTDjvI

Charliechong
Q14. If the power supply to the output stage is modulated,
this produces:
a) AM
b) MW
c) FM
d) PM
My answer: a).
The correct answer is c).?
Q15. A readability report R4 indicates:
a) unreadable
b) readable with considerable difficulty
c) readable with practically no difficulty
d) perfectly readable
My answer: b).

Charliechong
Signal Reports
黑豹
Readability Scale (R) Signal Strength Scale (S)
1. Hardly perceptible; unreadable
2. Weak; readable every now and then
3. Fairly good; readable but with
difficulty
4. Good; readable
5. Very good; perfectly readable
1. Unintelligible; barely perceptible
2. Weak signals; barely readable
3. Weak signals; but can be copied
4. Fair signals
5. Fairly good signals
6. Good signals
7. Moderately strong signals
8. Strong signals
9. Extremely strong signals

Charliechong
Signal Reports
黑豹
difficulty
4. Good; readable
4. Fair signals
6. Good signals
8. Strong signals
R4

Charliechong
Signal Reports
黑豹
difficulty
4. Good; readable
4. Fair signals
6. Good signals
8. Strong signals
2/3 3/1/2/3

Charliechong
R Scale
2/3
黑豹
5: Very
Good
4: Good
3: Fairly Good
2: Weak
1: Hardly/ unreadable

Charliechong
Signal Reports
黑豹
difficulty
4. Good; readable
4. Fair signals
6. Good signals
8. Strong signals
2/3 3/1/2/3
GoodWeak

Charliechong
Signal Reports
黑豹
difficulty
4. Good; readable
4. Fair signals
6. Good signals
8. Strong signals
2/3 3/1/2/3
GoodFairWeak Strong
Good
Weak

Charliechong
Strength Scales
4. Fair signals (Melody Fair).
黑豹
Signal Strength Scale (S)
4. Fair signals
6. Good signals
8. Strong signals

Charliechong
Q16. The o code for 'stand by' is:
a) ORN c) ORM
b) ORU d) ORX
My answer: To Read.
Q17. For safety the integrity of the earthing system should
be checked:
a) Every decade
b) When you move house
c) Periodically
d) Never
My answer: c).

Charliechong
Appendix 5: The International Q Code
Below are some of the International Q Codes commonly used in the Amateur
Service with their meanings, when used as a question and as a statement. The Q
signal procedurals are for use in Morse communications, but some have been
adopted into voice usage as well, with similar meanings.

Charliechong
QRG? : Will you tell me my exact frequency (or that of …………)?
Your exact frequency (or that of ……….) is.......... KHz.
QRH? : Does my frequency vary?
Your frequency varies.
QRI? : How/What is the tone of my transmission?
The tone of your transmission is.......... (1 = good, 2 = variable, 3 =
bad).
QRK? : What is the intelligibility of my signals (or those of ………)?
The intelligibility of your signals (or those of ………) is......... (1 =
bad, 2 = poor, 3 = fair, 4 = good, 5 = excellent).
QRL?
Voice
Usage
: Are you (or is the frequency) busy?
I am (or the frequency is) busy (with……….); please do not interfere.
(QRL is never spoken but it is customary to say “Is this frequency
in use?” before making a call on an apparently-free frequency)

Charliechong
QRM?
Voice
Usage
: Is my transmission being interfered with?
Your transmission is being interfered with ...…. (1 = nil, 2 = slightly,
3 = moderately, 4 = severely, 5 = extremely)
(QRM is sometimes spoken as “you’re getting QRMd” or “there’s a
lot of QRM” to indicate that the frequency is very congested)
QRN? : Are you troubled by static?
I am troubled by static ....…. (1 = nil, 2 = slightly, 3 = moderately, 4
= severely, 5 = extremely)
QRO? : Shall I increase transmitter (output) power?
Increase transmitter (output) power.

Charliechong
QRP?
Voice
Usage
: Shall I decrease transmitter (output) power?
Decrease transmitter (output) power.
(QRP has a more absolute “low power operation” meaning rather
than a relative “please lower your power” one. “Operating QRP”
refers to the sport of trying to make contacts with as low a power
as possible, usually 5 watts or less)

Charliechong
QRQ? : Shall I send faster?
Send faster (...... words per minute).
QRS? : Shall I send more slowly?
Send more slowly (...... words per minute).
QRT?
Voice
Usage
: Shall I stop sending?
Stop sending / I am leaving the air.
(QRT is sometimes used to indicate that one is signing off. “I’m
going QRT now”)
QRU? : Have you anything for me?
I have nothing for you.

Charliechong
QRV? : Are you ready?
I am ready.
QRW? : Shall I inform …….. that you are calling on ….. KHz?
Please inform …….. that I am calling on ….. KHz?
QRX? : When will you call me again?
Standby / I will call you again at ......hours on...... KHz.

Charliechong
QRZ?
Voice
Usage
: Who is calling me?
You are being called by ...... on..... KHz.
(QRZ is always spoken "Q R Zed" and is used when one catches
part of a call, particularly on an FM repeater, but can't tell which
station is being called. If I hear a friend of mine call someone, and
it might be me, but I'm not sure, I might say "QRZ for 9M2XXX?" It
can be used this way whenever there is doubt about whom the
calling station is calling or what they want)
QSA? : What is the strength of my signals (or those of ………)?
The strength of your signals (or those of ………) is...... (1 = barely
perceptible, 2 = weak, 3 = fairly good/okay, 4 = good, 5 = very
good).

Charliechong
QSB?: Are my signals fading?
Your signals are fading.
QSD? : Are my signals mutilated / Is my keying defective?
Your signals are mutilated / Your keying is defective.
QSG? : Shall I send ………. messages at a time? How many messages
should I send at a time?
Send ………….. messages at a time.
QSK? : Can you hear me between your signals and if so may I break in on
your transmissions?
I can hear you between my signals; break in on my transmissions.

Charliechong
QSL?
Voice
Usage
: Can you acknowledge receipt?
I acknowledge receipt.
(QSL when spoken either as a question or a statement has much
of the meaning of "okay" or "I understand" or "I will comply." "I'll
meet you later on at the house, QSL?" When communication
quality is poor, "QSL" is sometimes repeated three or more times
to indicate that the message was indeed received)
QSM? : Shall I repeat?
Repeat the last message you sent me (or message number
………).
QSN? : Did you hear me (or …………) on …………….KHz?
I heard you me (or …………) on …………….KHz

Charliechong
QSO?
Voice
Usage
: Can you communicate with ...….directly or by relay?
I can communicate with ...….directly (or via relay ………)
(QSO when spoken simply means "2-way contact." "Eyeball QSO"
refers to a face-to-face meeting)
QSP? : Will you relay to............?
I will relay to ….........

Charliechong
QST?
Voice
Usage
: Attention all radio amateurs:
(QST is usually used to introduce a broadcast message to all
amateurs (the only type of one-way message allowed on amateur
radio). “The following is a QST:”
QSU? : Shall I send or reply on this frequency (or on ………. KHz)?
Send or reply on this frequency (or on ………. KHz)
QSV? : Shall I send a series of V's for adjustment on this frequency?
Send a series of V's.
QSX? : Will you listen to ……… on ……… KHz?
I am listening to ……… on ……… KHz.

Charliechong
QSY?
Voice
Usage
: Shall I (Will you) change frequency (to ………..)?
I am changing frequency (to ……….)
(QSY when spoken is either a suggestion or an announcement
that one is changing frequencies. “QSY simplex?” is a suggestion
that the two conversing parties leave the repeater to another nonrepeater
frequency in order to free up the repeater resource.
Signing off using “this is KF9FF, QSY” conveys that I cannot be
reached on the current frequency any longer (lest anyone try).
QSZ? : Shall I send each word or group more than once?
Send each word or group twice.

Charliechong
QTA? : Shall I cancel message number ………..?
Cancel message number ………. .
QTB? : Do you agree with my counting of words?
I disagree with your count of words. I will repeat the first letter of
each word in the message.
QTH?
Voice
Usage
: What is your location?
My location is......
(QTH has the identical meaning as in Morse. "What's your QTH?"
"I'm nearly home").
QTR? : What is the correct time?
The correct time is ...... hours.

Charliechong
Q18. One quarter of one ampere may be written as:
a) 250 microampere c) 0.001 milliampere
b) 0.5ampere d) 250 milliampere
My answer: d).
Q19. An 'alternating current' is so called because:
a) it reverses direction periodically
b) it travels through a circuit using alternate paths
c) its direction of travel is uncertain
d) its direction or travel can be altered by a switch
My answer: a).

Charliechong
Q20. The type or transmission most prone to causing
Interference to an audio amplifier system is:
a) frequency modulation
b) frequency shift keying
c) amplitude modulation.
d) phase modulation
My answer: c).

Charliechong
Q21. An Ohm is equivalent to a:
a) Henry per Ampere c) Ampere per Volt
b) Joule per Coulomb d) Volt per Ampere
V= IR
R= V/I
My answer: d).
Q22. Watts are equivalent to:
a) V x I b) VII
c) V XV X t d) I x R
V= IR
My answer: d).

Charliechong
Q22. Watts are equivalent to:
a) V x I b) VII
C) V XV X t d) I x R
V= IR
Watt= Energy = I2Rt = IIR = IV#, for t=1s

Charliechong
Power
黑豹 https://www.slideshare.net/shreyaans/electricity-class-10-physics-chapter-complete-with-formulaehttps://www.facebook.com/puma4x4

Charliechong
Q23. Five 1500 Ohm transistors In parallel are equivalent to:
a) 60 Ohms c) 100 Ohms
b) 300 Ohms d) 7500 Ohms
I/R total = 5(1/1500) = 300Ω
My answer: b).
Q24. What are 4 good electrical Insulators?
a) Glass, air, plastic, porcelain
b) Paper, glass, air, aluminum
c) Glass, wood, cooper, porcelain
d) Plastic, rubber, wood, carbon
My answer: a).

Charliechong
Q25. A VHF/UHF transmitter should ideally be follow by:
a) a high pass fitter c) a crystal filter
b) a band pass filter d) a mains filter
LOW PASS FILTER FOR UHF TRANSMITTER: HOW ARE THEY USED?
If you are building a UHF transmitter, there is a high chance that you will need a low
pass filter for UHF transmitter. A UHF transmitter transmits an RF signal in the UHF
band, which could be anywhere in the frequency band from 300MHz to 1 GHz.
https://awgrf.com/low-pass-filter-uhf-transmitter/
My answer: b).

Charliechong
Q26. A multi-band antenna Is:
a) Less likely to radiate harmonics ,
b) More likely to radiate harmonics
c) Never going to radiate harmonics
d) More efficient than a dipole
My guess answer: b).
See: https://www.iasj.net/iasj?func=fulltext&aId=80903
Q27. What are electromagnetic waves
a) Alternating currents in the core or an electromagnet
b) A wave consisting of two electric fields at right angles to each other
c) A wave consisting of an electric field and a magnetic field at right angles to each
other
d) A wave consisting of two magnetic fields at right angles to each ether
My guess answer: c).

Charliechong
Q28. In digital communications, FSK stands for:
a) phase selection keying
b) frequency shift keying
c) final section keying
d) final signal keying
My guess answer: b).

Charliechong
Frequency-shift keying (FSK)
Frequency-shift keying (FSK) is a frequency modulation scheme in which digital
information is transmitted through discrete frequency changes of a carrier signal. The
technology is used for communication systems such as telemetry, weather balloon
radiosondes, caller ID, garage door openers, and low frequency radio transmission in
the VLF and ELF bands. The simplest FSK is binary FSK (BFSK). BFSK uses a pair of
discrete frequencies to transmit binary (0s and 1s) information. With this scheme, the
"1" is called the mark frequency and the "0" is called the space frequency.

Charliechong
Q29. In a Class B amplifiers, using an NPN transistor, the
base bias potential is:
a) much greater than the emitter potential
b) the same as the collector potential
c) about 0 .6V above the emitter voltage
d) less than the emitter voltage
My guess answer: c).
It should be 0.7V?

Charliechong
Class A B AB D & H Audio Amplifiers Explained
黑豹 https://youtu.be/9iqxvq9i0CQ

Charliechong
What are the differences between Class A, AB, and Class D
amplifiers?
黑豹 https://youtu.be/rj6h4qYxkCc

Charliechong
Generic Amplifier Circuit
黑豹 https://youtu.be/Rje5DJSe098

Charliechong
Class A & B Amplifiers
黑豹 https://youtu.be/2oTX_2RSjt8

Charliechong
Class A, B & AB Amplifiers
黑豹 https://youtu.be/oxC8isaaa7g

Charliechong
Introduction to Amplifiers: Class A
黑豹 https://youtu.be/x7LWkioxpIU

Charliechong
TTT136 Class A Transistor Amplifiers Pt1
https://www.youtube.com/results?search_query=TTT136+Class+A+Transistor+Amplifiers+Pt2
黑豹 https://youtu.be/FG4obc9SkPE

Amplifier
1. Introduction to the Amplifier
2. Common Emitter Amplifier
3. Common Source JFET Amplifier
4. Amplifier Distortion
5. Class A Amplifier
6. Class B Amplifier
7. Crossover Distortion in Amplifiers
8. Amplifiers Summary
9. Emitter Resistance
10. Amplifier Classes
11. Transistor Biasing
12. Input Impedance of an Amplifier
13. Frequency Response
14. MOSFET Amplifier
15. Class AB Amplifier
16. Common Collector Amplifier
Charliechong 黑豹 https://www.electronics-tutorials.ws/amplifier/amp_1.html

Charliechong
Q30. In the figure shown, 2 represents the:
a) Collector of a PNF transistor
b) Emitter of an NPN transistor
c) Base of an NPN transistor
d) Source of a junction FET
My answer: c).

Charliechong
Q31. Why would you use a fuse:
a) To create a short circuit when there Is too much current in a circulating
b) To change direct current into alternating current
c) To change alternating current into direct current
d) To create an open circuit when there is too much current in a circuit
My answer: d).
Q32. Which symbol of figure represents a fixed-value
capacitor
a) Symbol 1 c) Symbol 2
b) Symbol 3 d) Symbol 4
My answer: a).

Charliechong
Q33. In Figure 16-2, which symbol represents a variable
capacitor
a) Symbol 1 c) Symbol 2
b) Symbol 3 d) Symbol 4
My answer: b).
Should it be b). Figure 3?
黑豹 https://www.bing.com/images/search?view=detailV2&id=6E43A9217C9BEC6DC52623FBC09B8FA330C5A925&thid=OIP.IS9wmV84PYam10Eh3c5dHAAAAA&mediaurl=http%3A%2F%2Fwww.learnabout-electronics.org%2Fac_theory%2Fimages%2Fvariable-cap-symbols.gif&exph=256&expw=466&q=variable+capacitor+symbol&selectedindex=6&ajaxhist=0&vt=0&eim=0
Should it be b).
Figure 3?

Charliechong
Q34. What is a liquid crystal display (LCD)
a) A modem replacement for a quart crystal oscillator which displays its fundamental
frequency
b) A display that uses a crystalline liquid to change the way light is refracted
c) A frequency determining unit for a transmitter or receiver
d) A display that uses a glowing liquid to remain brightly lit in dim light
My guessed answer: d).
After Wikied my guessed answer: b).

Charliechong
LCD
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated
optical device that uses the light-modulating properties of liquid crystals. Liquid
crystals do not emit light directly, instead using a backlight or reflector to produce
images in color or monochrome. LCDs are available to display arbitrary images (as in
a general-purpose computer display) or fixed images with low information content,
which can be displayed or hidden, such as preset words, digits, and seven-segment
displays, as in a digital clock. They use the same basic technology, except that
arbitrary images are made up of a large number of small pixels, while other displays
have larger elements. LCDs can either be normally on (positive) or off (negative),
depending on the polarizer arrangement.
For example, a character positive LCD with a backlight will have black lettering on a
background that is the color of the backlight, and a character negative LCD will have a
black background with the letters being of the same color as the backlight. Optical
filters are added to white on blue LCDs to give them their characteristic appearance.
黑豹 https://en.wikipedia.org/wiki/Liquid-crystal_display

Charliechong
Q35. How is a voltmeter usually connected to a circuit under
test
a) in series with the circuit
b) in quadrature with the circuit
c) in parallel with the circuit
d) a phase with the circuit
My answer: a).

Charliechong
Measuring Voltage (in parallel)

Charliechong
Measuring Current (in series)

Charliechong
Q36. For which measurements would you normally use a
multimeter
a) SWR and power
b) resistance, capacitance & inductance
c) resistance and reactance
d) Voltage, current & resistance
My answer: d).

Charliechong
Q37. For safety reasons. across high value capacitors there
should always be:
a) an inductor
b) a bleed resistor
c) a short circuit
d) an open circuit
My answer: a).

Charliechong
Bleeder Resistor Basics
Role of Bleeder Resistors in Power Electronics Circuit:
In high voltage DC power supply, capacitors are used to smooth out the fluctuations in the output side. In AC to
DC rectifiers, the DC link capacitors are used to maintain the smooth DC waveform.
These capacitors store an electric charge for a while. In some power supplies, these filter capacitors hold the
full output voltage of the supply, like 600V even after the supply has been turned off.
We should not touch the DC link capacitors or Output filter capacitors immediately after turned off the supply.
The Bleeder resistors are connected across the filter capacitors to drain their stored charge so that servicing
the supply is not dangerous.
The Bleeder resistor is also known as Power Supply Drain Resistor.
The bleeder resistor R should have a value high enough so that it does not interfere with the operation of power
supply, but low enough so it will discharge the capacitor C, in a short time after the power supply has been shut
down.
In the figure, the Capacitor C is referred to as a reservoir capacitor. During the process of rectification, it stores
charge during the positive half-cycles of secondary voltage and releases it during the negative half-cycles.
Thus the power supply circuit is able to maintain a reasonably constant output voltage across load. But due to
parasitic effects C1 will discharge by a small amount during the negative half-cycle periods from the transformer
secondary.
This gives rise to a small variation in the d.c. output voltage (known as ripple voltage).
Since ripple is undesirable we must take additional precautions to reduce it. One method of reducing the ripple
voltage is increasing the discharge time constant. This can be achieved by increasing the value of C.
Thus for normal operation, the high value of C is important. At the same time, when the power supply is turned
off, this charge has to be removed.
黑豹 http://www.completepowerelectronics.com/bleeder-resistor-basics/https://www.facebook.com/puma4x4

Charliechong
Advantages of Bleeder Resistor
It improves the Voltage regulation. Being connected permanently across the supply it
causes an initial Voltage drop and on connecting the load their is a slightly additional
voltage drop. Thus the Difference between the no load voltage and full load voltage is
reduced thereby increasing the voltage Regulation.
It provides the safety to the operator by providing a discharge path to the capacitor.
When Power supply is switched off the filter capacitor discharges through it.
That is why it is called BLEEDER RESISTOR.
黑豹 https://www.mycircuits9.com/2012/06/bleeder-resistor-advantages-and-circuit.htmlhttps://www.facebook.com/puma4x4

Charliechong
Q38. The following unit in a DC power supply performs a
rectifying operation
a) an electrolytic capacitor
b) a fuse
c) A crowbar
d) a full-wave diode bridge
My answer: d).
黑豹 https://www.dnatechindia.com/Tutorial/Diode/Full-Wave-Rectifier.html

Charliechong
Bleeder Resistor
Definition: Bleeder Resistor is a standard resistor which is connected in parallel with the capacitor of the filter
circuit to provide discharging of the capacitor. If the capacitor is not discharged properly, then it may lead to an
electric shock to the person operating it.
黑豹 https://electronicscoach.com/bleeder-resistor.html

Charliechong
Q39. The capacitor value best suited for filtering the output
of 12 volt 1 amp DC power supply is;
a) 100 pF c) 10 nF
b) 100 nF d) 10,000 uF
C = Q/V
C =
It
V
C =
1t
12
=
1x 0.01
12
106 = 833μF#
t = half cycle time for 50Hz DC (10ms)
My answer: d).
Read more:
https://www.electronics-notes.com/articles/electronic_components/capacitors/capacitor-uses.php
黑豹 https://www.youtube.coam/embed/J9HsLWmtBnE

Charliechong
Why and How to use capacitor | Basic electronics Tutorials
黑豹 https://www.youtube.com/embed/XXWlCUiUxuY

Charliechong
What is a Capacitor? Learn the Physics of Capacitors &
How they work - Basic Electronics Tutorial
黑豹 https://www.youtube.com/embed/CmII_BmOf0I

Charliechong
Full Bridge rectifier - capacitor value, voltage selection
黑豹 https://www.youtube.com/embed/J9HsLWmtBnE

Charliechong
Q40. The block diagram below representing a circuit for:
a) voltage stabilization
b) rectification
c) reverse bias protection
d) voltage multiplication
My answer: b).
On second thought, based on the description provided ―Regulated Power Supply‖
My second thought answer: a).
黑豹
 Rectification block diagram
 Stabilization block diagram

Charliechong
Q41. The block marked ·regulator in the diagram is to;
a) Regulate the incoming mains voltage to a constant value
b) Ensure that the output voltage never exceeds a dangerous value
c) Keep the incoming frequency constant at 50Hz
d) Keep the output voltage at a constant value
My answer: d).
Q42. The block marked transformer in the diagram is to;
a) Transform the incoming mains AC voltage to a DC voltage
b) Ensure that any RF radiation cannot get into the power supply
c) Transform the mains AC voltage to a more convenient AC voltage
d) Transform the mains AC waveform into a higher frequency waveform
My answer: a).
黑豹

Charliechong
Q43. The block marked rectifier in the diagram Is to;
a) the AC voltage from the transformer Into a fluctuating DC voltage
b) Rectify any waveform errors introduced by the transformer
c) Tum the sine wave output of the rectifier into a square wave
d) Remove any AC components from the output of the transformer
My answer: a).

Charliechong
Q44. Which type of oscillator circuits are commonly used in
a VFO (variable frequency oscillator)?
a) Pieroe & Zener
b) Colpitts & Hartley
c) Armstrong & deforest
d) Negative feedback & batanoed feedback
On Youtube_ed
My answer: b).

Charliechong
Variable Frequency Oscillators (VFO)
黑豹 https://www.youtube.com/embed/i5qzbIis5cg

Charliechong
A Zener diode
A Zener diode is a particular type of diode that, unlike a normal one, allows current to
flow not only from its anode to its cathode, but also in the reverse direction, when
the Zener voltage is reached.
Zener diodes have a highly doped p-n junction. Normal diodes will also break
down with a reverse voltage but the voltage and sharpness of the knee are not as well
defined as for a Zener diode. Also normal diodes are not designed to operate in the
breakdown region, but Zener diodes can reliably operate in this region.
The device was named after Clarence Melvin Zener, who discovered the Zener effect.
Zener reverse breakdown is due to electron quantum tunnelling caused by a high-
strength electric field. However, many diodes described as "Zener" diodes rely instead
on avalanche breakdown. Both breakdown types are used in Zener diodes with the
Zener effect predominating under 5.6 V and avalanche breakdown above.
Zener diodes are widely used in electronic equipment of all kinds and are one of the
basic building blocks of electronic circuits. They are used to generate low power
stabilized supply rails from a higher voltage and to provide reference voltages for
circuits, especially stabilized power supplies. They are also used to protect circuits
from overvoltage, especially electrostatic discharge (ESD).
黑豹

Charliechong
What is Zener Diode
黑豹 https://www.youtube.com/embed/XhQqtdTlRus

Charliechong
Zener Diode
Electron Tunneling/ Avalanche
黑豹
V=IR
R=
10.1
40.9
𝑥1000, Rz = 246Ω
V=IR
R=
9.94
2.06
𝑥1000, Rz = 4825Ω

V=IR
R=
10.1
40.9
𝑥1000, Rz = 246Ω
V=IR
R=
9.94
2.06
𝑥1000, Rz = 4825Ω
Charliechong 黑豹
How Zener Diode Works?
During reverse voltage applied across the Zener diode exceeds the
rated voltage of the device a process called Avalanche
Breakdown occurs in the semiconductor depletion layer and a current
starts to flow through the diode to limit this increase in voltage.
https://www.electronics-tutorials.ws/diode/diode_7.html
Zener Diode
Electron Tunneling/ Avalanche

Charliechong
The Pierce oscillator
The Pierce oscillator is a type of electronic
oscillator particularly well-suited for use in
piezoelectric crystal oscillator circuits. Named for
its inventor, George W. Pierce (1872–1956), the
Pierce oscillator is a derivative of the Colpitts
oscillator. Virtually all digital IC clock oscillators
are of Pierce type, as the circuit can be
implemented using a minimum of components: a
single digital inverter, one resistor, two
capacitors, and the quartz crystal, which acts as
a highly selective filter element. The low
manufacturing cost of this circuit and the
outstanding frequency stability of the quartz
crystal give it an advantage over other designs
in many consumer electronics applications.
黑豹
Simplified Pierce oscillator. Positive voltage is applied
to collector of transistor, usually via a resistor or
choke.
https://en.wikipedia.org/wiki/Pierce_oscillator

Charliechong
The Pierce oscillator
The circuit shown to the right is known as a Pierce oscillator. This is a simple, very
conventional oscillator circuit, which works quite well as long as the transistor doesn't
generate too much noise.
Feedback is through the crystal, of course, and the operating frequency is trimmed by
adjusting C1. Of course, the circuit cannot be tuned over a range, but it does lend
itself to switching between different crystals, thus allowing this oscillator to cover
different frequency bands.
C2 serves to bypass some of the feedback energy, and thereby keep the output sine
wave cleaner. Without C2, the output waveform would be more of a square wave than
a sine wave.
The Pierce oscillator typically is built using a parallel mode crystal operating at its
fundamental frequency.
黑豹 http://www.play-hookey.com/oscillators/crystal/pierce_oscillator.html

Charliechong
Crystal oscillator
A crystal oscillator is an electronic oscillator circuit that uses the mechanical
resonance of a vibrating crystal of piezoelectric material to create an electrical signal
with a precise frequency. This frequency is often used to keep track of time, as in
quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and
to stabilize frequencies for radio transmitters and receivers. The most common type of
piezoelectric resonator used is the quartz crystal, so oscillator circuits incorporating
them became known as crystal oscillators, but other piezoelectric materials including
polycrystalline ceramics are used in similar circuits. A crystal oscillator, particularly one
using a quartz crystal, works by distorting the crystal with an electric field, when
voltage is applied to an electrode near or on the crystal. This property is known as
electrostriction or inverse piezoelectricity. When the field is removed, the quartz -
which oscillates in a precise frequency - generates an electric field as it returns to its
previous shape, and this can generate a voltage. The result is that a quartz crystal
behaves like an RLC circuit, but with a much higher Q. Quartz crystals are
manufactured for frequencies from a few tens of kilohertz to hundreds of megahertz.
More than two billion crystals are manufactured annually[citation needed]. Most are
used for consumer devices such as wristwatches, clocks, radios, computers, and
cellphones. Quartz crystals are also found inside test and measurement equipment,
such as counters, signal generators, and oscilloscopes.
黑豹 https://en.wikipedia.org/wiki/Crystal_oscillator

Charliechong
Crystal oscillator
黑豹
Simple Pierce oscillator
https://en.wikipedia.org/wiki/Pierce_oscillator

Charliechong
Colpitts oscillator
黑豹 https://www.electronics-tutorials.ws/oscillator/colpitts.html

Charliechong
Q45. What type of circuit does figure T7-2 represent if block
1 is a product detector
a) a simple phase modulation receiver
b) a simple FM receiver
c) a simple CW and SSB receiver
d) a double conversion multiplier

Charliechong
CW Transceiver

Charliechong
Ham Radio Basics- What is SSB and How to Tune in SSB
黑豹 https://www.youtube.com/embed/QiQYS9gMDyc

Charliechong
Q46. if figure T7·2 is a diagram of a simple single-sideband
receiver, what type of circuit should be shown in block 1?
a) a high pass filler
b) a ratio detector
c) a low pass filter
d) a product detector
My guessed answer: c).

Charliechong 黑豹
Detector
In radio, a detector is a device or circuit that extracts information from a modulated radio
frequency current or voltage. The term dates from the first three decades of radio (1888-1918).
Unlike modern radio stations which transmit sound (an audio signal) on an uninterrupted carrier
wave, early radio stations transmitted information by radiotelegraphy. The transmitter was
switched on and off to produce long or short periods of radio waves, spelling out text messages
in Morse code. Therefore, early radio receivers had only to distinguish between the presence or
absence of a radio signal. The device that performed this function in the receiver circuit was
called a detector.[1] A variety of different detector devices, such as the coherer, electrolytic
detector, magnetic detector and the crystal detector, were used during the wireless telegraphy
era until superseded by vacuum tube technology.
After sound (amplitude modulation, AM) transmission began around 1920, the term evolved to
mean a demodulator, (usually a vacuum tube) which extracted the audio signal from the radio
frequency carrier wave. This is its current meaning, although modern detectors usually consist of
semiconductor diodes, transistors, or integrated circuits.
In a superheterodyne receiver the term is also sometimes used to refer to the mixer, the tube or
transistor which converts the incoming radio frequency signal to the intermediate frequency. The
mixer is called the first detector, while the demodulator that extracts the audio signal from the
intermediate frequency is called the second detector.
In microwave and millimeter wave technology the terms detector and crystal detector refer to
waveguide or coaxial transmission line components, used for power or SWR measurement, that
typically incorporate point contact diodes or surface barrier Schottky diodes.
https://en.wikipedia.org/wiki/Detector_(radio)

Charliechong
Envelope detector
One major technique is known as envelope detection. The simplest form of envelope
detector is the diode detector that consists of a diode connected between the input
and output of the circuit, with a resistor and capacitor in parallel from the output of the
circuit to the ground to form a low pass filter. If the resistor and capacitor are correctly
chosen, the output of this circuit will be a nearly identical voltage-shifted version of the
original signal.
An early form of envelope detector was the crystal detector, which was used in the
crystal set radio receiver. A later version using a crystal diode is still used in crystal
radio sets today. The limited frequency response of the headset eliminates the RF
component, making the low pass filter unnecessary.
More sophisticated envelope detectors include the grid-leak detector, the plate
detector, the infinite-impedance detector, transistor equivalents of them and precision
rectifiers using operational amplifiers.
黑豹
A simple envelope detector

Charliechong
Product detector
A product detector is a type of demodulator used for AM and SSB signals. Rather than
converting the envelope of the signal into the decoded waveform like an envelope
detector, the product detector takes the product of the modulated signal and a local
oscillator, hence the name. A product detector is a frequency mixer.
Product detectors can be designed to accept either IF or RF frequency inputs. A
product detector which accepts an IF signal would be used as a demodulator block in
a superheterodyne receiver, and a detector designed for RF can be combined with an
RF amplifier and a low-pass filter into a direct-conversion receiver.
黑豹 https://en.wikipedia.org/wiki/Product_detector

Charliechong
Product detector
A product detector is an electronic circuit that brings out the message from an
amplitude-modulated carrier or a single-sideband (SSB) carrier. It is based on the
mathematical model of the message translated in the frequency domain by an amount
known as the radio frequency (RF) carrier frequency. The product detector may or
may not use a frequency mixer to recover the message from the modulated or
message-modified carrier.
In communication circuits, the message, which can be voice, is combined or used to
modulate an RF carrier. The envelope of the carrier then becomes the carrier attribute
that carries the original message. To recover the message, called modulation, an
envelope detector or demodulator is used. In amplitude modulation (AM), the simple
diode detector rectifies the carrier to produce a direct current (DC) with an average
level that is proportional to the original message. In SSB, the product detector, along
with additional circuits, will reconstruct the message even if only one of the two
sidebands is available.
黑豹 https://www.wisegeek.com/what-is-a-product-detector.htm

Charliechong 黑豹 https://www.wisegeek.com/what-is-a-product-detector.htm
It is possible in an AM radio receiver to amplify the incoming RF once, and then feed the
result into a frequency mixer together with a local oscillator equal to the incoming frequency.
The output of the frequency mixer will have a few significantly strong outputs. There will be
a signal in the frequency range of the message that will be available at the output of the
mixer. Moreover, there will be other products like a signal with a frequency equal to the sum
of the incoming RF and the local oscillator. If the filter at the mixer output passes only the
message, only the message will be recovered by an envelope detector, which is a
simplified product detector.
A simple product detector may be implemented using four diodes in a circuit similar to a
gating circuit. When one of the two input signals is at 0 volts (V), there is lack of forward
bias in the diodes to allow the other input to reach the output. The resulting signal is a time-
domain product, which results in a frequency-domain addition or subtraction of the
message band or the base band. This is the original message.
In AM, the RF carrier and both sidebands are available in the carrier. One technique used
in saving power and bandwidth is to make use of SSB. In the SSB transmitter, the output
does not have a carrier and one of the sidebands. When the SSB carrier is transmitted into
the air and received, it is easy to notice when the SSB audio received turns into a duck-like
sound, while the resulting message will tend to shift in audio frequency. One option is to
equip an SSB receiver with a very accurate and stable carrier frequency reference so that
the product detector will be able to demodulate the message with minimal distortion in
terms of phase and frequency.

Charliechong
Product Detector Components
黑豹 https://www.youtube.com/embed/qbCoql_OPMw

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
47 What circuit Is pictured in figure 17-3, if block 1 is a
frequency discriminator
a) a double-conversion receiver
b) a variable-frequency oscillator
c) a superheterodyne receiver
d) an FM receiver z

Charliechong
Product Detector Components
黑豹 https://www.youtube.com/embed/x9hnbzF9XC8

Charliechong
What is a frequency discriminator?
黑豹 https://www.youtube.com/embed/WxJdUo7dnNM

Charliechong
FM Discriminator?
黑豹 https://www.youtube.com/embed/k0Gx5YqefoE

Charliechong
Frequency Discriminator
A discriminator circuit that delivers an output voltage which is proportional to the
deviations of a signal from a predetermined frequency value.
Superheterodyne
A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that
uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF)
which can be more conveniently processed than the original carrier frequency. It was
invented by US engineer Edwin Armstrong in 1918 during World War I. Virtually all
modern radio receivers use the superheterodyne principle.

Charliechong
Question from 48 10 53 relates to this diagram below

Charliechong
Q48. In the transmitter block diagram shown the „oscillator'
a) Is variable in frequency
b) Generates an audio frequency tone during tests
c) Uses a crystal for goal frequency stability
d) May have a calibrated dial
My guessed answer: b).
Q49. In the transmitter block diagram shown, the 'balanced
modulator'
a) Balances the high and low frequencies in the audio signal
b) Performs double sideband suppresses carrier modulation
c) Acts as a tone control
d) Balances the standing wave ratio

Charliechong 黑豹 https://www.wisegeek.com/what-is-a-balanced-modulator.htm
Balanced Modulator
A balanced modulator is a device that modifies a signal, usually in the form of an
amplitude modulated (AM) radio signal. It takes the original signal that has both
sidebands and a carrier signal, and then modulates it so that only the sideband signals
come through the output modulator. This creates a balanced signal, as there is less
noise because the carrier signal has been removed.
Amplitude modulation is a way for a signal to be transmitted over distances. The AM
signal is originally sent with a carrier signal in the form of a wave, which is then
modulated, or changed, by an audio signal that is also in the form of a wave. This
produces a signal that has the original carrier signal plus two bands, one on top of the
original and one on the bottom. These are referred to as sidebands and are exact
copies of each other. A signal like this is called a double-sideband amplitude
modulated (DSB-AM) signal.
The sidebands, because they were modified by the originating audio waveform, are
the signals responsible for carrying the information that is being transmitted. Once
modulated, the carrier signal doesn’t serve a real practical purpose anymore, and it
only shows that a signal is being sent. It does, however, take up a larger chunk of
power than the two sideband signals, and also creates a less-clear signal.

Charliechong
Q50. In the transmitter block diag. shown, the 'filter'
a) Removes mails hum from the audio signal
b) Suppresses unwanted harmonics of the RF signal
c) Removes one sideband from the modulated signal
d) Removes the carrier component from the modulated Signal
Q51. In the transmitter block diagram shown the 'mixer‟
a) Adds the correct proportion of carrier to the SSB signal
b) Mixes the audio and RF signals in the correct proportions
c) Translates the SSB signal to the required frequency
d) Mixes the two sidebands in the correct proportions
My guessed answer: c).

Charliechong
Q52. In the transmitter block diagram shown, the 'linear
amplifier”
a) Has all components arranged in-line
b) Amplifies the modulated signal with no distortion
c) Aligns the two sidebands correctly
d) Removes any unwanted amplitude modulation from the signal
Q53. In the transmitter block diagram shown the 'VFO' is
a) A voice frequency oscillator
b) A virtual faze oscillalor
c) A variable fixed oscillator
d) A variable frequency oscillator

Charliechong
How an FM Transceiver Works
黑豹 https://www.youtube.com/embed/lRPeEPazdOI

Charlie Chong/ Fion ZhangCharlie Chong/ Fion Zhang

Charliechong
The handbook

Charliechong
Superheterodyne Reoeiver

Charliechong
Appendix 2: Class of Emission Code
Emissions are classified and symbolized according to their basic characteristics.
The basic characteristics are:
a) First symbol – type of modulation of the main carrier;
b) Second symbol – nature of signal(s) modulating the main carrier; and
c) Third symbol – type of information to be transmitted.
黑豹

Charliechong
i) Basic characteristic
1. First 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
黑豹

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 pre-established
sequence, in a combination of two or more of the following modes:
amplitude, angle, pulse.
X Cases not otherwise covered
黑豹

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
X Cases not otherwise covered
黑豹

Charliechong
Help in emergencies and natural disasters situations
by providing immediate communications whenever normal communications service is
failed or unavailable.
黑豹

Charliechong
PART B: AMATEUR RADIO OPERATING
PROCEDURES (AOP)
黑豹

Charlie Chong/ Fion ZhangCharlie Chong

Charlie Chong/ Fion Zhang
The primary participants needed for conducting an audit are the auditor, the auditee, and the
client.
 The person conducting the audit is called the auditor, lead auditor, or audit team leader.
 The organization being audited or investigated is called the auditee.
 There is also a client, the person or organization that has requested the audit.

Summary
• How would you define quality audit?
• How would you define quality inspection?
• What are the phases of audits?
• What are the 2 types of audits based on
supplier-customer relationship?
• Briefly descries 1st/2nd and 3rd party audits.
• What are the 3 levels/areas of audit that
could be performed on an organization?
• What are the reference documents to be
audited of the above 3 levels of audit areas?
• What are the primary participants of an
audit?
• Who calls for audit?
• What could be audited?
• What are the common audit criteria?
• What could be reported in the audit report?
• Is an auditor inspector?

Summary
• How would you define quality audit?
A planned, independent, and documented assessment to determine whether agreed-upon
requirements are being met. It is a management tool.
• How would you define quality inspection?
Inspection is a tool to detect errors or defects before a product is approved for release or
distribution.
• What are the phases of audits?
Preparation, performance, report, follow- up and closure.
• What are the 2 types of audits based on supplier-
customer relationship?
Internal and external.
• Briefly descries 1st/ 2nd and 3rd party audits.
• What are the 3 levels/areas of audit that could be
performed on an organization?
System, process and product including service audits.
• What are the reference documents to be audited of the
above 3 levels of audit areas?
• What are the primary participants of an audit?
Auditor, Auditee and the Client.
• Who calls for audit?
The Client.
• What could be audited?
Anything.
• What are the common audit criteria?
• What could be reported in the audit report?
nonconformities/conformities, findings, non-compliances/compliances, defects,
concerns, effective, not-effective, strength, weak, good points, bad practices
etc.
• Is an auditor inspector? No.

Charlie Chong/ Fion Zhang
Part II
Audit Process
[42 of the CQA Exam Questions or 28 percent]
_________________________________________________________
Chapter 6 Audit Preparation and Planning/Part IIA
Chapter 7 Audit Performance/Part IIB
Chapter 8 Audit Reporting/Part IIC
Chapter 9 Audit Follow- up and Closure/Part IID

Radio amateur examination q01 q50

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