Canadian (from VE2AAY) Basic Qualification pool, section L10

Subelement L10

Modulation and Transmitters.

Section L10

B-3-2-1

In a frequency modulation transmitter, the input to the speech amplifier is connected to the:

A.
frequency multiplier
Correct Answer
B.
microphone
C.
modulator
D.
power amplifier

B-3-2-1

key words: INPUT to SPEECH AMPLIFIER. The Speech Amplifier serves to bring up the feeble microphone signal to a working level. The FM Transmitter block diagram: Microphone, Speech Amplifier, Modulator, Oscillator, Frequency Multiplier, Power Amplifier, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-2-2

In a frequency modulation transmitter, the microphone is connected to the:

A.
modulator
B.
power amplifier
C.
oscillator
Correct Answer
D.
speech amplifier

B-3-2-2

The Speech Amplifier serves to bring up the feeble microphone signal to a working level. The FM Transmitter block diagram: Microphone, Speech Amplifier, Modulator, Oscillator, Frequency Multiplier, Power Amplifier, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-2-3

In a frequency modulation transmitter, the ____________is in between the speech amplifier and the oscillator.

A.
power amplifier
B.
microphone
C.
frequency multiplier
Correct Answer
D.
modulator

B-3-2-3

key words: FM TANSMITTER. Frequency Modulation depends on frequency deviation to carry the message. The obvious way to effect deviation is to use modulation to alter the Oscillator frequency. The FM Transmitter block diagram: Microphone, Speech Amplifier, Modulator, Oscillator, Frequency Multiplier, Power Amplifier, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-2-4

In a frequency modulation transmitter, the __________is located between the modulator and the frequency multiplier.

A.
microphone
Correct Answer
B.
oscillator
C.
speech amplifier
D.
power amplifier

B-3-2-4

The Oscillator frequency and the deviation impressed on it by the Modulator are brought up to the operating frequency through multiplication. The FM Transmitter block diagram: Microphone, Speech Amplifier, Modulator, Oscillator, Frequency Multiplier, Power Amplifier, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-2-5

In a frequency modulation transmitter, the ___________is located between the oscillator and the power amplifier.

Correct Answer
A.
frequency multiplier
B.
microphone
C.
speech amplifier
D.
modulator

B-3-2-5

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-2-6

In a frequency modulation transmitter, the _________ is located between the frequency multiplier and the antenna.

A.
oscillator
Correct Answer
B.
power amplifier
C.
modulator
D.
speech amplifier

B-3-2-6

In all transmitters, the last stage before the Antenna is a Power Amplifier which imparts the transmitted signal its actual power. The FM Transmitter block diagram: Microphone, Speech Amplifier, Modulator, Oscillator, Frequency Multiplier, Power Amplifier, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-2-7

In a frequency modulation transmitter, the power amplifier output is connected to the:

A.
modulator
Correct Answer
B.
antenna
C.
frequency multiplier
D.
microphone

B-3-2-7

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-4-1

In a CW transmitter, the output from the __________ is connected to the driver/buffer.

A.
telegraph key
B.
power supply
Correct Answer
C.
master oscillator
D.
power amplifier

B-3-4-1

To achieve stability (absence of frequency 'drift'), Master Oscillators are always low-power stages. Amplification must follow; that's the purpose of the Driver/Buffer. The CW Transmitter block diagram: Master Oscillator, Driver/Buffer, Power Amplifier, Antenna. A Power Supply supplies DC to all stages. A Telegraph Key activates the Driver and Power Amplifier when pressed.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-4-2

In a typical CW transmitter, the ___________ is the primary source of direct current.

A.
driver/buffer
B.
power amplifier
C.
master oscillator
Correct Answer
D.
power supply

B-3-4-2

ALL transmitters require a Power Supply, the primary source of Direct Current (DC), required by active devices such as transistors and vacuum tubes. The CW Transmitter block diagram: Master Oscillator, Driver/Buffer, Power Amplifier, Antenna. A Power Supply supplies DC to all stages. A Telegraph Key activates the Driver and Power Amplifier when pressed.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-4-3

In a CW transmitter, the _________ is between the master oscillator and the power amplifier.

Correct Answer
A.
driver/buffer
B.
audio amplifier
C.
power supply
D.
telegraph key

B-3-4-3

To achieve stability, Master Oscillators are always low-level stages. Amplification must follow; that's the purpose of the Driver/Buffer. The CW Transmitter block diagram: Master Oscillator, Driver/Buffer, Power Amplifier, Antenna. A Power Supply supplies DC to all stages. A Telegraph Key activates the Driver and Power Amplifier when pressed.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-4-4

In a CW transmitter, the _____________ controls when RF energy is applied to the antenna.

A.
driver/buffer
B.
power amplifier
Correct Answer
C.
telegraph key
D.
master oscillator

B-3-4-4

Telegraphy is equivalent to 'on-off keying' ( an 'interrupted carrier'). The Telegraph Key allows the operator to send bursts of RF energy to the antenna per the rhythm of his hand movement on the key. The CW Transmitter block diagram: Master Oscillator, Driver/Buffer, Power Amplifier, Antenna. A Power Supply supplies DC to all stages. A Telegraph Key activates the Driver and Power Amplifier when pressed.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-4-5

In a CW transmitter, the ______________ is in between the driver/buffer stage and the antenna.

Correct Answer
A.
power amplifier
B.
power supply
C.
telegraph key
D.
master oscillator

B-3-4-5

In all transmitters, the last stage before the Antenna is a Power Amplifier which imparts the transmitted signal its actual power. The CW Transmitter block diagram: Master Oscillator, Driver/Buffer, Power Amplifier, Antenna. A Power Supply supplies DC to all stages. A Telegraph Key activates the Driver and Power Amplifier when pressed.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-4-6

In a CW transmitter, the output of the _____________ is transferred to the antenna.

A.
power supply
B.
master oscillator
Correct Answer
C.
power amplifier
D.
driver/buffer

B-3-4-6

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-1

In a single sideband transmitter, the output of the ________ is connected to the balanced modulator.

A.
variable frequency oscillator
B.
linear amplifier
C.
mixer
Correct Answer
D.
radio frequency oscillator

B-3-6-1

The Balanced Modulator receives two inputs: RF Oscillator, Speech Amplifier. The SSB Transmitter block diagram: The Balanced Modulator takes in two signals: fixed frequency from an RF Oscillator and the microphone signal after it has passed through a Speech Amplifier. Out of the Balanced Modulator, a Filter selects the desired sideband. This SSB signal is mixed with a Variable Frequency Oscillator (VFO) signal by a Mixer. Out of the Mixer, the SSB signal is now at the operating frequency and is taken through a LINEAR Power Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-2

In a single sideband transmitter, the output of the ____________ is connected to the filter.

Correct Answer
A.
balanced modulator
B.
microphone
C.
mixer
D.
radio frequency oscillator

B-3-6-2

The Balanced Modulator produces a double-sideband suppressed-carrier signal. The Filter keeps one sideband. The SSB Transmitter block diagram: The Balanced Modulator takes in two signals: fixed frequency from an RF Oscillator and the microphone signal after it has passed through a Speech Amplifier. Out of the Balanced Modulator, a Filter selects the desired sideband. This SSB signal is mixed with a Variable Frequency Oscillator (VFO) signal by a Mixer. Out of the Mixer, the SSB signal is now at the operating frequency and is taken through a LINEAR Power Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-3

In a single sideband transmitter, the _____________ is in between the balanced modulator and the mixer.

A.
speech amplifier
B.
microphone
Correct Answer
C.
filter
D.
radio frequency oscillator

B-3-6-3

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-4

In a single sideband transmitter, the ______________ is connected to the speech amplifier.

A.
filter
B.
mixer
Correct Answer
C.
microphone
D.
radio frequency oscillator

B-3-6-4

The Speech Amplifier serves to bring up the feeble microphone signal to a working level. The SSB Transmitter block diagram: The Balanced Modulator takes in two signals: fixed frequency from an RF Oscillator and the microphone signal after it has passed through a Speech Amplifier. Out of the Balanced Modulator, a Filter selects the desired sideband. This SSB signal is mixed with a Variable Frequency Oscillator (VFO) signal by a Mixer. Out of the Mixer, the SSB signal is now at the operating frequency and is taken through a LINEAR Power Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-5

In a single sideband transmitter, the output of the ___________ is connected to the balanced modulator.

Correct Answer
A.
speech amplifier
B.
filter
C.
variable frequency oscillator
D.
linear amplifier

B-3-6-5

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-6

In a single sideband transmitter, the output of the variable frequency oscillator is connected to the __________.

A.
linear amplifier
Correct Answer
B.
mixer
C.
antenna
D.
balanced modulator

B-3-6-6

The Mixer takes in the SSB signal and the VFO output to bring up the SSB signal at the operating frequency. The SSB Transmitter block diagram: The Balanced Modulator takes in two signals: fixed frequency from an RF Oscillator and the microphone signal after it has passed through a Speech Amplifier. Out of the Balanced Modulator, a Filter selects the desired sideband. This SSB signal is mixed with a Variable Frequency Oscillator (VFO) signal by a Mixer. Out of the Mixer, the SSB signal is now at the operating frequency and is taken through a LINEAR Power Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-7

In a single sideband transmitter, the output of the _________ is connected to the mixer.

A.
linear amplifier
B.
antenna
Correct Answer
C.
variable frequency oscillator
D.
radio frequency oscillator

B-3-6-7

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-8

In an single sideband transmitter, the ____________ is in between the mixer and the antenna.

A.
balanced modulator
B.
radio frequency oscillator
Correct Answer
C.
linear amplifier
D.
variable frequency oscillator

B-3-6-8

In SSB, the Power Amplifier must be linear because it amplifies an amplitude modulated signal. The SSB Transmitter block diagram: The Balanced Modulator takes in two signals: fixed frequency from an RF Oscillator and the microphone signal after it has passed through a Speech Amplifier. Out of the Balanced Modulator, a Filter selects the desired sideband. This SSB signal is mixed with a Variable Frequency Oscillator (VFO) signal by a Mixer. Out of the Mixer, the SSB signal is now at the operating frequency and is taken through a LINEAR Power Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-6-9

In a single sideband transmitter, the output of the linear amplifier is connected to the ______________.

A.
speech amplifier
Correct Answer
B.
antenna
C.
filter
D.
variable frequency oscillator

B-3-6-9

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-1

What does chirp mean?

Correct Answer
A.
A small change in a transmitter's frequency each time it is keyed
B.
A high-pitched tone which is received along with a CW signal
C.
A slow change in transmitter frequency as the circuit warms up
D.
An overload in a receiver's audio circuit whenever CW is received

B-3-11-1

"Chirp": Inadequate voltage regulation causes the Master Oscillator frequency to shift when the Telegraph Key is pressed. Perceived at the receive location as a change of pitch during each Morse element. Frequency 'drift' is a lack of stability in the Master Oscillator.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-2

What can be done to keep a CW transmitter from chirping?

A.
Add a low pass filter
Correct Answer
B.
Keep the power supply voltages very steady under transmit load
C.
Add a key-click filter
D.
Keep the power supply current very steady under transmit load

B-3-11-2

"Chirp": Inadequate voltage regulation causes the Master Oscillator frequency to shift when the Telegraph Key is pressed. Perceived at the receive location as a change of pitch during each Morse element. Current varies as demand varies in a transmitter. A Low-Pass filter reduces 'harmonics'.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-3

What circuit has a variable-frequency oscillator connected to a buffer/driver and a power amplifier?

A.
A single-sideband transmitter
B.
A digital radio transmitter
Correct Answer
C.
A VFO-controlled CW transmitter
D.
A crystal-controlled AM transmitter

B-3-11-3

key words: VFO, Variable Frequency Oscillator. The CW Transmitter block diagram: Master Oscillator, Driver/Buffer, Power Amplifier, Antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-4

What type of modulation system changes the amplitude of an RF wave for the purpose of conveying information?

A.
Phase modulation
B.
Amplitude-rectification modulation
C.
Frequency modulation
Correct Answer
D.
Amplitude modulation

B-3-11-4

key word: AMPLITUDE. The instantaneous voltage of an AC waveform. AM (Amplitude Modulation) impresses the message onto the RF carrier by varying its amplitude.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-5

In what emission type does the instantaneous amplitude (envelope) of the RF signal vary in accordance with the modulating audio?

Correct Answer
A.
Amplitude modulation
B.
Frequency modulation
C.
Pulse modulation
D.
Frequency shift keying

B-3-11-5

key word: AMPLITUDE. The instantaneous voltage of an AC waveform. AM (Amplitude Modulation) impresses the message onto the RF carrier by varying its amplitude.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-6

Morse code is usually transmitted by radio as:

A.
a series of key-clicks
B.
a continuous carrier
C.
a voice-modulated carrier
Correct Answer
D.
an interrupted carrier

B-3-11-6

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-7

A mismatched antenna or transmission line may present an incorrect load to the transmitter. The result may be:

Correct Answer
A.
full power will not be transferred to the antenna
B.
loss of modulation in the transmitted signal
C.
the driver stage will not deliver power to the final
D.
the output tank circuit breaks down

B-3-11-7

The 'Final' = the Power Amplifier. A serious impedance mismatch in the antenna system forces the Power Amplifier to operate in a load for which it was not designed. A significant mismatch causes high SWR (Standing Wave Ratio) which leads to voltage and current peaks which could damage the Power Amplifier.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-8

One result of a slight mismatch between the power amplifier of a transmitter and the antenna would be:

A.
smaller DC current drain
B.
lower modulation percentage
C.
radiated key-clicks
Correct Answer
D.
reduced antenna radiation

B-3-11-8

Impedance Match: maximum power transfer occurs when the impedance of the load matches the internal impedance of the source. A "slight mismatch" leads to reduced power being delivered to the antenna.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-9

An RF oscillator should be electrically and mechanically stable. This is to ensure that the oscillator does not:

Correct Answer
A.
drift in frequency
B.
become over modulated
C.
generate key-clicks
D.
cause undue distortion

B-3-11-9

key word: STABLE. Absence of frequency "drift". A good oscillator remains on frequency despite mechanical vibrations, voltage or temperature variations.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-10

The input power to the final stage of your transmitter is 200 watts and the output is 125 watts. What has happened to the remaining power?

A.
It has been used to provide greater efficiency
B.
It has been used to provide negative feedback
C.
It has been used to provide positive feedback
Correct Answer
D.
It has been dissipated as heat loss

B-3-11-10

Power Amplifiers have a certain 'efficiency', the ratio of DC power required to obtain an RF output. The difference goes up in heat. This is the reason for the 'heat sinks' on the back of transmitters.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-11-11

The difference between DC input power and RF output power of a transmitter RF amplifier:

A.
is due to oscillating
B.
radiates from the antenna
Correct Answer
C.
appears as heat dissipation
D.
is lost in the transmission line

B-3-11-11

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-1

What may happen if an SSB transmitter is operated with the microphone gain set too high?

A.
It may cause digital interference to computer equipment
Correct Answer
B.
It may cause splatter interference to other stations operating near its frequency
C.
It may cause interference to other stations operating on a higher frequency band
D.
It may cause atmospheric interference in the air around the antenna

B-3-12-1

key words: MICROPHONE GAIN SET TOO HIGH. This leads to 'overmodulation' evidenced by distorted speech plus using excessive bandwidth on the air (splatter) which interferes with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-2

What may happen if an SSB transmitter is operated with too much speech processing?

A.
It may cause digital interference to computer equipment
B.
It may cause atmospheric interference in the air around the antenna
C.
It may cause interference to other stations operating on a higher frequency band
Correct Answer
D.
It may cause audio distortion or splatter interference to other stations operating near its frequency

B-3-12-2

key words: TOO MUCH SPEECH PROCESSING. 'Speech processing' is raising the average amplitude of the audio input from the microphone closer to an acceptable peak value: i.e., make every passage of the spoken words equally loud. Too much speech processing leads to distortion and possibly driving the Linear Power Amplifier with too large a signal (overdriving). This leads to 'overmodulation' evidenced by distorted speech plus occupying excessive bandwidth on the air (splatter) which interferes with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-3

What is the term for the average power supplied to an antenna transmission line during one RF cycle, at the crest of the modulation envelope?

A.
Average radio-frequency power
B.
Peak transmitter power
Correct Answer
C.
Peak envelope power
D.
Peak output power

B-3-12-3

key word: ENVELOPE. PEP -- Peak Envelope Power ( a specification for SSB transmitters ): the average power at the output of a transmitter during one cycle at a modulation peak.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-4

What is the usual bandwidth of a single-sideband amateur signal?

A.
Between 3 and 6 kHz
Correct Answer
B.
Between 2 and 3 kHz
C.
1 kHz
D.
2 kHz

B-3-12-4

By transposing the voice signal into the radio spectrum, the SSB transmitter manages to only use the approximate bandwidth of the original modulation ( speech frequencies important for communications span 300 hertz to 3000 hertz, a bandwidth of 2700 hertz ). SSB uses half the bandwidth of AM.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-5

In a typical single-sideband phone transmitter, what circuit processes signals from the balanced modulator and sends signals to the mixer?

Correct Answer
A.
Filter
B.
IF amplifier
C.
RF amplifier
D.
Carrier oscillator

B-3-12-5

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-6

What is one advantage of carrier suppression in a double-sideband phone transmission?

A.
Only half the bandwidth is required for the same information content
B.
Greater modulation percentage is obtainable with lower distortion
C.
Simpler equipment can be used to receive a double-sideband suppressed-carrier signal
Correct Answer
D.
More power can be put into the sidebands for a given power amplifier capacity

B-3-12-6

Plain AM (Amplitude Modulation) produces a radio Carrier, an upper sideband and a lower sideband. The sidebands are the ever-changing sum and differences of the modulating frequency (follows voice) and the carrier frequency (set at the operating frequency). The carrier by itself does NOT convey information. The message is in the sidebands. Suppressing the carrier permits using the full capacity of the Power Amplifier for the sidebands. Note: Suppressing the carrier an one sideband yields Single Sideband.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-7

What happens to the signal of an overmodulated single-sideband or double-sideband phone transmitter?

Correct Answer
A.
It becomes distorted and occupies more bandwidth
B.
It becomes stronger with no other effects
C.
It occupies less bandwidth with poor high-frequency response
D.
It has higher fidelity and improved signal-to-noise ratio

B-3-12-7

key word: OVERMODULATED. 'Overmodulation' results in distorted speech plus using excessive bandwidth on the air (splatter) and interfering with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-8

How should the microphone gain control be adjusted on a single-sideband phone transmitter?

A.
For a dip in plate current
Correct Answer
B.
For slight movement of the ALC meter on modulation peaks
C.
For full deflection of the ALC meter on modulation peaks
D.
For 100% frequency deviation on modulation peaks

B-3-12-8

ALC -- Automatic Level Control: a feedback circuit from the Linear Power Amplifier to an earlier amplifier stage which seeks to avoid overdriving the transmitter with too much audio. When the ALC acts, it is a corrective action. An infrequent ALC action on modulation peaks indicates that there is no overdriving. If the ALC needed to intervene constantly, this would indicate that the operator is trying to feed too much audio through the transmitter.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-9

The purpose of a balanced modulator in an SSB transmitter is to:

A.
ensure that the percentage of modulation is kept constant
B.
make sure that the carrier and both sidebands are in phase
Correct Answer
C.
suppress the carrier and pass on the two sidebands
D.
make sure that the carrier and both sidebands are 180 degrees out of phase

B-3-12-9

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-10

In a SSB transmission, the carrier is:

A.
transmitted with one sideband
B.
inserted at the transmitter
C.
of no use at the receiver
Correct Answer
D.
reinserted at the receiver

B-3-12-10

In Amplitude Modulation, the position, along the radio spectrum, of a 'side frequency' within a sideband is the sum (or difference) of the modulating frequency and carrier frequency. The statement is also true with Single Sideband (SSB) where the carrier has been suppressed: the position of a 'side frequency' only has meaning in relation with the position of the phantom carrier. Suitable demodulation at the receiving end supposes that the "carrier is re-inserted" so that each side frequency (a great number of which form a sideband) can be rendered as an exact audio frequency.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-12-11

The automatic level control (ALC) in a SSB transmitter:

A.
increases the occupied bandwidth
B.
reduces the system noise
Correct Answer
C.
controls the peak audio input so that the power amplifier is not overdriven
D.
reduces transmitter audio feedback

B-3-12-11

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-1

What may happen if an FM transmitter is operated with the microphone gain or deviation control set too high?

Correct Answer
A.
It may cause interference to other stations operating near its frequency
B.
It may cause digital interference to computer equipment
C.
It may cause atmospheric interference in the air around the antenna
D.
It may cause interference to other stations operating on a higher frequency band

B-3-13-1

key words: MICROPHONE GAIN, DEVIATION TOO HIGH. 'Overdeviation (FM)' or 'Overmodulation (AM, SSB)' results in distorted speech plus using excessive bandwidth on the air (splatter) and interfering with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-2

What may your FM hand-held or mobile transceiver do if you shout into its microphone and the deviation adjustment is set too high?

A.
It may cause interference to other stations operating on a higher frequency band
Correct Answer
B.
It may cause interference to other stations operating near its frequency
C.
It may cause digital interference to computer equipment
D.
It may cause atmospheric interference in the air around the antenna

B-3-13-2

key word: SHOUT. 'Overdeviation (FM)' or 'Overmodulation (AM, SSB)' results in distorted speech plus using excessive bandwidth on the air (splatter) and interfering with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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B-3-13-3

What can you do if you are told your FM hand-held or mobile transceiver is overdeviating?

Correct Answer
A.
Talk farther away from the microphone
B.
Talk louder into the microphone
C.
Let the transceiver cool off
D.
Change to a higher power level

B-3-13-3

key word: OVERDEVIATION. 'Overdeviation (FM)' or 'Overmodulation (AM, SSB)' results in distorted speech plus using excessive bandwidth on the air (splatter) and interfering with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-4

What kind of emission would your FM transmitter produce if its microphone failed to work?

A.
A phase-modulated carrier
Correct Answer
B.
An unmodulated carrier
C.
A frequency-modulated carrier
D.
An amplitude-modulated carrier

B-3-13-4

The concept here is that IF NO AUDIO is fed in an FM transmitter, the carrier put out at the Power Amplifier has full amplitude anyway. A carrier which conveys no message is an 'unmodulated carrier'.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-5

Why is FM voice best for local VHF/UHF radio communications?

A.
Its RF carrier stays on frequency better than the AM modes
Correct Answer
B.
It provides good signal plus noise to noise ratio at low RF signal levels
C.
The carrier is not detectable
D.
It is more resistant to distortion caused by reflected signals

B-3-13-5

FM -- Frequency Modulation. As the process removes much of the ambient electrical noise, weak signals can be rendered with better 'signal plus noise' to 'noise' ratio. However, this comes at a price of more occupied bandwidth, 10 to 20 kilohertz in usual amateur communications.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-6

What is the usual bandwidth of a frequency-modulated amateur signal for +/- 5kHz deviation?

A.
Greater than 20 kHz
Correct Answer
B.
Between 10 and 20 kHz
C.
Less than 5 kHz
D.
Between 5 and 10 kHz

B-3-13-6

In order of bandwidth requirements: CW = about 100 Hz, RTTY = about 600 Hz, SSB = 2 to 3 kHz, FM = 10 to 20 kHz.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-7

What is the result of overdeviation in an FM transmitter?

A.
Poor carrier suppression
Correct Answer
B.
Out-of-channel emissions
C.
Increased transmitter power
D.
Increased transmitter range

B-3-13-7

'Overdeviation (FM)' or 'Overmodulation (AM, SSB)' results in distorted speech plus using excessive bandwidth on the air (splatter) and interfering with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-8

What emission is produced by a reactance modulator connected to an RF power amplifier?

A.
Pulse modulation
Correct Answer
B.
Phase modulation
C.
Multiplex modulation
D.
Amplitude modulation

B-3-13-8

Direct FM: Use a variable reactance element as one of the elements of an oscillator to cause frequency deviation. Indirect FM: apply the modulating voltage to a variable reactance element connected to a tuned circuit later in the transmit chain, where it will produce phase modulation rather than frequency modulation.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-9

Why isn't frequency modulated (FM) phone used below 28.0 MHz?

Correct Answer
A.
The bandwidth would exceed limits in the Regulations
B.
The transmitter efficiency for this mode is low
C.
Harmonics could not be attenuated to practical levels
D.
The frequency stability would not be adequate

B-3-13-9

The usual bandwidth of FM with 5 kHz deviation on amateur bands is between 10 to 20 kilohertz. On the 10 metre band (28.0 to 29.7 MHz), maximum permitted bandwidth is 20 kHz. "Radiotelephone signals in a frequency band below 29.50 MHz cannot be automatically retransmitted unless these signals are received from a station operated by a person qualified to transmit on frequencies below 29.50 MHz (RBR-4, formerly RIC-2)."

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-3-13-10

You are transmitting FM on the 2 metre band. Several stations advise you that your transmission is loud and distorted. A quick check with a frequency counter tells you that the transmitter is on the proper frequency. Which of the following is the most probable cause of the distortion?

A.
The power supply output voltage is low
B.
The repeater is reversing your sidebands
C.
The frequency counter is giving an incorrect reading and you are indeed off frequency
Correct Answer
D.
The frequency deviation of your transmitter is set too high

B-3-13-10

key word: DISTORTION. 'Overdeviation (FM)' or 'Overmodulation (AM, SSB)' results in distorted speech plus using excessive bandwidth on the air (splatter) and interfering with stations using adjacent frequencies ('out-of-channel emissions').

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

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