Transcript 06 2018 Multi-Mode Radio Excitementx

Technician Licensing Class
Multi-Mode Radio Excitement
Section 6
Valid July 1, 2014
Through
June 30, 2018
Multi-Mode Radio Excitement
A “transceiver” combines both transmitting and
receiving functions in one package
•
T7A02
•
T7A09
A multi-mode VHF transceiver is most useful for VHF
weak-signal communication.
Multi-Mode Radio Excitement
Modulation is the process of applying information
(voice, video, or digital) onto a radio signal
T7A08
Multi-Mode Radio Excitement
4
Multi-Mode Radio Excitement
Single sideband is a form of amplitude
modulation.
 T8A01
Carrier only CW
•
Tones produce
both side bands or
AM
Remove one
sideband and
suppress carrier
becomes SSB
Single Sideband (SSB) is the type of voice mode is most
often used for long-distance (weak signal) contacts on the
VHF and UHF bands.
T8A03
Multi-Mode Radio Excitement
•
The primary advantage of single sideband over FM
for voice transmissions is that SSB signals have narrower
bandwidth
•
3 kHz is the approximate bandwidth of a single
sideband voice signal.
•
For single sideband -- 2400 Hz would be the
appropriate receive filter to minimize noise and interference
•
The upper sideband is normally used for 10 meter HF,
VHF and UHF single-sideband communications
T8A07
T8A08
T4B09
T8A06
Multi-Mode Radio Excitement
The use of SSB phone is permitted in at least some
portion of all the amateur bands above 50 MHz
• T4B06 The receiver RIT or clarifier controls could be used if
the
voice pitch of a single-sideband signal seems too high or
low.
•
T2B13
•
T4B7
The term "RIT" means Receiver Incremental
.
Set knobTuning
to neutral,
press RIT button to
turn on function, and
then adjust slightly
for proper SSB voice
reception
RIT adjusts voice pitch, not the frequency of received station.
Multi-Mode Radio Excitement
• T4A1
•
Some microphone connectors on
amateur transceivers include push-to-talk
functions and voltage links for powering
the microphone.
An oscillator is a circuit that generates a signal of a
desired frequency.
T7A05
Multi-Mode Radio Excitement
CW (Continuous Wave or Morse Code) is the type of
emission that has the narrowest bandwidth.
•
T8A05
•
T8A11
150 Hz is the approximate maximum bandwidth
required to transmit a CW signal.
CW Signal
150 Hz wide
SSB Signal
2 - 3 kHz wide
FM Signal
5 - 15 kHz wide
UHF Fast-Scan TV
~ 6 MHz
Multi-Mode Radio Excitement
•
500 Hz is an appropriate receive filter to select in
order to minimize noise and interference for CW
reception.
T4B10
• Bandwidth filters vary for the mode being received.
•
The advantage of having multiple receive bandwidth
choices on a multimode transceiver will permit noise or
interference reduction by selecting a bandwidth
matching the mode.
T4B08
Multi-Mode Radio Excitement
•
The function of a mixer is to convert a radio signal
from one frequency to another.
T7A03
Station
Signal
MIXER
Signal A at
800 kHz (or at
1200 kHz)
Signal C at
455 kHz
(In AM Broadcast
Receiver)
Intermediate
Frequency
Local
Oscillator
Signal B at
1255 kHz (or
at 1655 kHz)
Block Diagram of an AM Broadcast Receiver Mixer
Multi-Mode Radio Excitement
• T7A04
Selectivity is the term that describes the ability of a
• T7A01
Sensitivity is the ability of a receiver to detect the
• T4B12
AGC or automatic gain control is used to keep
receiver to discriminate between multiple signals.
presence of a signal.
received audio relatively constant.
An RF pre-amp is installed between the antenna input and the
receiver.
• T7A11
Multi-Mode Excitement
•
A transverter is a device that takes the output of
a low-powered 28 MHz SSB exciter and produces a
222 MHz output signal.
T7A06
Your First Radio
Preventing voltage fluctuations from reaching
sensitive circuits is a good reason to use a regulated
power supply for communications equipment.
T4A03
MFJ-4125
13.8VDC@22Amp
Jetstream JTPS30M
Regulated Power Supply
Take Aways
Take Aways
 A “transceiver” combines both transmitting and receiving
functions in one package
 A multi-mode VHF transceiver is most useful for VHF
weak-signal communication.
 Modulation is the process of applying information (voice,
video, or digital) onto a radio signal
 Single sideband is a form of amplitude modulation
 Single Sideband (SSB) is the type of voice mode is most often
used for long-distance (weak signal) contacts on the VHF
and UHF bands.
Take Aways
 The primary advantage of single sideband over FM for voice
transmissions is that SSB signals have narrower bandwidth
 3 kHz is the approximate bandwidth of a single sideband
voice signal. (3 kHz equals 3000 Hz)
 For single sideband 2400 Hz would be the appropriate
receive filter to minimize noise and interference
 The upper sideband is normally used for 10 meter HF, all
VHF and all UHF single-sideband communications
Take Aways
 The use of SSB phone is permitted in at least some portion of
all the amateur bands above 50 MHz
 The receiver RIT or clarifier controls could be used if the
voice pitch of a single-sideband signal seems too high or
low.
 The term "RIT" means Receiver Incremental Tuning.
•
Some microphone connectors on amateur transceivers
include push-to-talk functions and voltage links for powering
the microphone.
•
An oscillator is a circuit that generates a signal of a desired
Take Aways
 In comparison to SSB and FM, CW emission has the narrowest
bandwidth.
 The approximate maximum bandwidth to transmit a CW
signal is 150 Hz
 An appropriate receive filter used in order to minimize noise
and interference for CW reception is 500 Hz.
 The advantage of having multiple receive bandwidth choices
on a multimode transceiver permits noise or interference
reduction by selecting a bandwidth matching the mode.
Take Aways
 The function of a mixer is to convert a radio signal from one
frequency to another
 Selectivity is the term that describes the ability of a receiver
to discriminate between multiple signals.
 Sensitivity is the ability of a receiver to detect the resence of
a signal.
 AGC or automatic gain control is used to keep received
audio relatively constant.
 An RF pre-amp is installed between the antenna input and
the receiver.
Take Aways
 A transverter is a device that takes the output of a lowpowered 28 MHz SSB exciter and produces a 222 MHz
output signal.
 Preventing voltage fluctuations from reaching sensitive
circuits is a good reason to use a regulated power supply
for communications equipment.
Element 2 Technician Class
Question Pool
Multi-Mode
Radio Excitement
Valid July 1, 2014
Through
June 30, 2018
T7A02
What is a transceiver?
A. A type of antenna switch
B. A unit combining the functions of a
transmitter and receiver
C. A component in a repeater which filters
out unwanted interference
D. A type of antenna matching network
23
T7A09
Which of the following devices is most useful for
VHF weak-signal communication?
A.
B.
C.
D.
A quarter-wave vertical antenna
A multi-mode VHF transceiver
An omni-directional antenna
A mobile VHF FM transceiver
24
T8A03
Which type of voice mode is most often used for
long-distance (weak signal) contacts on the VHF
and UHF bands ?
A.
B.
C.
D.
FM
DRM
SSB
PM
25
T8A07
What is the primary advantage of single sideband
over FM for voice transmissions?
A.
B.
C.
D.
SSB signals are easier to tune
SSB signals are less susceptible to interference
SSB signals have narrower bandwidth
All of these choices are correct
26
T8A01
Which of the following is a form of amplitude
modulation?
A.
B.
C.
D.
Spread-spectrum
Packet radio
Single sideband
Phase shift keying
27
T8A06
Which sideband is normally used for 10 meter
HF, VHF and UHF single-sideband
communications?
A.
B.
C.
D.
Upper sideband
Lower sideband
Suppressed sideband
Inverted sideband
28
T7A08
Which of the following describes
combining speech with an RF carrier signal?
A.
B.
C.
D.
Impedance matching
Oscillation
Modulation
Low-pass filtering
29
T8A08
What is the approximate bandwidth of a single
sideband voice signal?
A.
B.
C.
D.
1 kHz
3 kHz
6 kHz
15 kHz
30
T4B09
Which of the following is an appropriate receive
filter bandwidth to select in order to minimize noise
and interference for SSB reception?
A.
B.
C.
D.
500 Hz
1000 Hz
2400 Hz
5000 Hz
31
T2B13
Which of the following is true of the use of SSB
phone in amateur bands above 50 MHz?
A. It is permitted only by holders of a General
Class or higher license
B. It is permitted only on repeaters
C. It is permitted in at least some portion of all
the amateur bands above 50 MHz
D. It is permitted only on when power is limited
to no more than 100 watts
32
T4B06
Which of the following controls could be used if the
voice pitch of a single-sideband signal seems too
high or low?
A.
B.
C.
D.
The AGC or limiter
The bandwidth selection
The tone squelch
The receiver RIT or clarifier
33
T4B07
What does the term "RIT" mean?
A.
B.
C.
D.
Receiver Input Tone
Receiver Incremental Tuning
Rectifier Inverter Test
Remote Input Transmitter
34
T4A01
Which of the following is true concerning the
microphone connectors on amateur transceivers?
A. All transceivers use the same microphone
connector type
B. Some connectors include push-to-talk and
voltages for powering the microphone
C. All transceivers using the same connector
type are wired identically
D. Un-keyed connectors allow any microphone
to be connected
35
T7A05
What is the name of a circuit that generates
a signal of a desired frequency?
A.
B.
C.
D.
Reactance modulator
Product detector
Low-pass filter
Oscillator
36
T8A05
Which of the following types of emission has the
narrowest bandwidth?
A.
B.
C.
D.
FM voice
SSB voice
CW
Slow-scan TV
37
T8A11
What is the approximate maximum bandwidth
required to transmit a CW signal?
A.
B.
C.
D.
2.4 kHz
150 Hz
1000 Hz
15 kHz
38
T4B10
Which of the following is an appropriate receive filter
bandwidth to select in order to minimize noise and
interference for CW reception?
A.
B.
C.
D.
500 Hz
1000 Hz
2400 Hz
5000 Hz
39
T4B08
What is the advantage of having multiple
receive bandwidth choices on a multimode
transceiver?
A. Permits monitoring several modes at once
B. Permits noise or interference reduction by
selecting a bandwidth matching the mode
C. Increases the number of frequencies that can
be stored in memory
D. Increases the amount of offset between
receive and transmit frequencies
40
T7A01
Which term describes the ability of a receiver to
detect the presence of a signal?
A.
B.
C.
D.
Linearity
Sensitivity
Selectivity
Total Harmonic Distortion
41
T7A03
Which of the following is used to convert a radio
signal from one frequency to another?
A.
B.
C.
D.
Phase splitter
Mixer
Inverter
Amplifier
42
T7A04
Which term describes the ability of a receiver to
discriminate between multiple signals?
A.
B.
C.
D.
Discrimination ratio
Sensitivity
Selectivity
Harmonic Distortion
43
T4B12
What is the function of automatic gain control or
AGC?
A.
B.
C.
D.
To keep received audio relatively constant
To protect an antenna from lightning
To eliminate RF on the station cabling
asymmetric goniometer control used for
antenna matching
44
T7A11
Where is an RF preamplifier installed?
A. Between the antenna and the receiver
B. At the output of the transmitter’s power
amplifier
C. Between transmitter and antenna tuner
D. At the receiver’s audio output
45
T7A06
What device takes the output of a low-powered
28 MHz SSB exciter and produces a 222 MHz
output signal?
A.
B.
C.
D.
High-pass filter
Low-pass filter
Transverter
Phase converter
46
T4A03
Which is a good reason to use a regulated power
supply for communications equipment?
A. It prevents voltage fluctuations from reaching
sensitive circuits
B. A regulated power supply has FCC approval
C. A fuse or circuit breaker regulates the power
D. Power consumption is independent of load
47