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General License Ham Radio > Sub Element G4: Amateur Radio Practices > Flashcards

Sub Element G4: Amateur Radio Practices Flashcards

1
Q

What is the purpose of the “notch filter” found on many HF transceivers?

A

To reduce interference from carriers in the receiver passband.

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2
Q

What is one advantage of selecting the opposite, or “reverse,” sideband when receiving CW signals on a typical HF transceiver?

A

It may be possible to reduce or eliminate interference from other signals

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3
Q

What is normally meant by operating a transceiver in “split” mode?

A

The transceiver is set to different transmit and receive frequencies

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4
Q

What reading on the plate current meter of a vacuum tube RF power amplifier indicates correct adjustment of the plate tuning control?

A

A pronounced dip

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5
Q

What is a reason to use Automatic Level Control (ALC) with an RF power amplifier?

A

To reduce distortion due to excessive drive

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6
Q

What type of device is often used to match transmitter output impedance to an impedance not equal to 50 ohms?

A

Antenna coupler or antenna tuner

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7
Q

What condition can lead to permanent damage to a solid-state RF power amplifier?

A

Excessive drive power

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8
Q

What is the correct adjustment for the load or coupling control of a vacuum tube RF power amplifier?

A

Maximum power output without exceeding maximum allowable plate current

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9
Q

Why is a time delay sometimes included in a transmitter keying circuit?

A

To allow time for transmit-receive changeover operations to complete properly before RF output is allowed

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10
Q

What is the purpose of an electronic keyer?

A

Automatic generation of strings of dots and dashes for CW operation

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11
Q

Which of the following is a use for the IF shift control on a receiver?

A

To avoid interference from stations very close to the receive frequency

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12
Q

Which of the following is a common use for the dual-VFO feature on a transceiver?

A

To permit monitoring of two different frequencies

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13
Q

What is one reason to use the attenuator function that is present on many HF transceivers?

A

To reduce signal overload due to strong incoming signals

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14
Q

What is likely to happen if a transceiver’s ALC system is not set properly when transmitting AFSK signals with the radio using single sideband mode?

A

Improper action of ALC distorts the signal and can cause spurious emissions

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15
Q

Which of the following can be a symptom of transmitted RF being picked up by an audio cable carrying AFSK data signals between a computer and a transceiver?

A

The VOX circuit does not un-key the transmitter

The transmitter signal is distorted

Frequent connection timeouts

All these choices are correct

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16
Q

How does a noise blanker work?

A

By reducing receiver gain during a noise pulse

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17
Q

What happens as the noise reduction control level in a receiver is increased?

A

Received signals may become distorted

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18
Q

What item of test equipment contains horizontal and vertical channel amplifiers?

A

An oscilloscope

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19
Q

Which of the following is an advantage of an oscilloscope versus a digital voltmeter?

A

Complex waveforms can be measured

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20
Q

Which of the following is the best instrument to use when checking the keying waveform of a CW transmitter?

A

An oscilloscope

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21
Q

What signal source is connected to the vertical input of an oscilloscope when checking the RF envelope pattern of a transmitted signal?

A

The attenuated RF output of the transmitter

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22
Q

Why is high input impedance desirable for a voltmeter?

A

It decreases the loading on circuits being measured

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23
Q

What is an advantage of a digital voltmeter as compared to an analog voltmeter?

A

Better precision for most uses

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24
Q

What signals are used to conduct a two-tone test?

A

Two non-harmonically related audio signals

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25
Q

Which of the following instruments may be used to monitor relative RF output when making antenna and transmitter adjustments?

A

A field strength meter

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26
Q

Which of the following can be determined with a field strength meter?

A

The radiation pattern of an antenna

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27
Q

Which of the following can be determined with a directional wattmeter?

A

Standing wave ratio

28
Q

Which of the following must be connected to an antenna analyzer when it is being used for SWR measurements?

A

Antenna and feed line

29
Q

What problem can occur when making measurements on an antenna system with an antenna analyzer?

A

Strong signals from nearby transmitters can affect the accuracy of measurements

30
Q

What is a use for an antenna analyzer other than measuring the SWR of an antenna system?

A

Determining the impedance of coaxial cable

31
Q

What is an instance in which the use of an instrument with analog readout may be preferred over an instrument with a digital readout?

A

When adjusting tuned circuits

32
Q

What type of transmitter performance does a two-tone test analyze?

A

Linearity

33
Q

Which of the following might be useful in reducing RF interference to audio frequency devices?

A

Bypass capacitor

34
Q

Which of the following could be a cause of interference covering a wide range of frequencies?

A

Arcing at a poor electrical connection

35
Q

What sound is heard from an audio device or telephone if there is interference from a nearby single sideband phone transmitter?

A

Distorted speech

36
Q

What is the effect on an audio device when there is interference from a nearby CW transmitter?

A

On-and-off humming or clicking

37
Q

What might be the problem if you receive an RF burn when touching your equipment while transmitting on an HF band, assuming the equipment is connected to a ground rod?

A

The ground wire has high impedance on that frequency

38
Q

What effect can be caused by a resonant ground connection?

A

High RF voltages on the enclosures of station equipment

39
Q

Why should soldered joints not be used with the wires that connect the base of a tower to a system of ground rods?

A

A soldered joint will likely be destroyed by the heat of a lightning strike

40
Q

Which of the following would reduce RF interference caused by common-mode current on an audio cable?

A

Placing a ferrite choke around the cable

41
Q

How can a ground loop be avoided?

A

Connect all ground conductors to a single point

42
Q

What could be a symptom of a ground loop somewhere in your station?

A

You receive reports of “hum” on your station’s transmitted signal

43
Q

What technique helps to minimize RF “hot spots” in an amateur station?

A

Bonding all equipment enclosures together

44
Q

Which of the following is an advantage of a receiver DSP IF filter as compared to an analog filter?

A

A wide range of filter bandwidths and shapes can be created

45
Q

Why must the metal enclosure of every item of station equipment be grounded?

A

It ensures that hazardous voltages cannot appear on the chassis

46
Q

What is the purpose of a speech processor as used in a modern transceiver?

A

Increase the intelligibility of transmitted phone signals during poor conditions

47
Q

Which of the following describes how a speech processor affects a transmitted single sideband phone signal?

A

It increases average power

48
Q

Which of the following can be the result of an incorrectly adjusted speech processor?

A

Distorted speech

Splatter

Excessive background pickup

All these choices are correct

49
Q

What does an S meter measure?

A

Received signal strength

50
Q

How does a signal that reads 20 dB over S9 compare to one that reads S9 on a receiver, assuming a properly calibrated S meter?

A

It is 100 times more powerful

51
Q

Where is an S meter found?

A

In a receiver

52
Q

How much must the power output of a transmitter be raised to change the S meter reading on a distant receiver from S8 to S9?

A

Approximately 4 times

53
Q

What frequency range is occupied by a 3 kHz LSB signal when the displayed carrier frequency is set to 7.178 MHz?

A

7.175 to 7.178 MHz

54
Q

What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?

A

14.347 to 14.350 MHz

55
Q

How close to the lower edge of the phone segment should your displayed carrier frequency be when using 3 kHz wide LSB?

A

At least 3 kHz above the edge of the segment

56
Q

How close to the upper edge of the phone segment should your displayed carrier frequency be when using 3 kHz wide USB?

A

At least 3 kHz below the edge of the band

57
Q

What is the purpose of a capacitance hat on a mobile antenna?

A

To electrically lengthen a physically short antenna

58
Q

What is the purpose of a corona ball on an HF mobile antenna?

A

To reduce RF voltage discharge from the tip of the antenna while transmitting

59
Q

Which of the following direct, fused power connections would be the best for a 100 watt HF mobile installation?

A

To the battery using heavy-gauge wire

60
Q

Why is it best NOT to draw the DC power for a 100 watt HF transceiver from a vehicle’s auxiliary power socket?

A

The socket’s wiring may be inadequate for the current drawn by the transceiver

61
Q

Which of the following most limits an HF mobile installation?

A

Efficiency of the electrically short antenna

62
Q

What is one disadvantage of using a shortened mobile antenna as opposed to a full- size antenna?

A

Operating bandwidth may be very limited

63
Q

Which of the following may cause receive interference in a radio installed in a vehicle?

A

The battery charging system
The fuel delivery system
The vehicle control computer
All these choices are correct

64
Q

What is the name of the process by which sunlight is changed directly into electricity?

A

Photovoltaic conversion

65
Q

What is the approximate open-circuit voltage from a fully illuminated silicon photovoltaic cell?

A

0.5 VDC

66
Q

What is the reason that a series diode is connected between a solar panel and a storage battery that is being charged by the panel?

A

The diode prevents self-discharge of the battery though the panel during times of low or no illumination

General License Ham Radio (10 decks)

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