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FCC G4C - 业余无线电实践与电台操作

FCC 题库总览 > G级 (通用级 General) > G4 业余无线电实践与电台操作 > G4C

小节 G4C：业余无线电实践与电台操作

本小节共包含 12 道中英双语精校考题
#G4C01🔗
Which of the following might be useful in reducing RF interference to audio frequency circuits?
以下哪项可能有助于减少对音频电路的射频干扰？
A
Bypass inductor
旁路电感
B
Bypass capacitor
旁路电容
✓ 正确答案
C
Forward-biased diode
正向偏置二极管
D
Reverse-biased diode
反向偏置二极管
#G4C02🔗
Which of the following could be a cause of interference covering a wide range of frequencies?
以下哪项可能是造成大范围频率干扰的原因？
A
Not using a balun or line isolator to feed balanced antennas
不使用巴伦或线路隔离器为平衡天线供电
B
Lack of rectification of the transmitter’s signal in power conductors
电源导体中的发射器信号缺乏整流
C
Arcing at a poor electrical connection
电气连接不良时产生电弧
✓ 正确答案
D
Using a balun to feed an unbalanced antenna
使用巴伦为不平衡天线供电
#G4C03🔗
What sound is heard from an audio device experiencing RF interference from a single sideband phone transmitter?
受到单边带电话发射器射频干扰的音频设备会听到什么声音？
A
A steady hum whenever the transmitter is on the air
发射机在广播时发出稳定的嗡嗡声
B
On-and-off humming or clicking
断断续续的嗡嗡声或咔哒声
C
Distorted speech
言语扭曲
✓ 正确答案
D
Clearly audible speech
讲话清晰可闻
#G4C04🔗
What sound is heard from an audio device experiencing RF interference from a CW transmitter?
受到 CW 发射器射频干扰的音频设备会听到什么声音？
A
On-and-off humming or clicking
断断续续的嗡嗡声或咔哒声
✓ 正确答案
B
A CW signal at a nearly pure audio frequency
近乎纯音频的 CW 信号
C
A chirpy CW signal
啁啾的 CW 信号
D
Severely distorted audio
音频严重失真
#G4C05🔗
What is a possible cause of high voltages that produce RF burns?
产生射频烧伤的高电压可能是什么原因？
A
Flat braid rather than round wire has been used for the ground wire
地线采用扁编织线而非圆线
B
Insulated wire has been used for the ground wire
地线已使用绝缘线
C
The ground rod is resonant
接地棒谐振
D
The ground wire has high impedance on that frequency
地线在该频率上具有高阻抗
✓ 正确答案
#G4C06🔗
What is a possible effect of a resonant ground connection?
谐振接地连接可能产生什么影响？
A
Overheating of ground straps
接地带过热
B
Corrosion of the ground rod
接地棒腐蚀
C
High RF voltages on the enclosures of station equipment
车站设备外壳上的高射频电压
✓ 正确答案
D
A ground loop
接地环路
#G4C07🔗
Why should soldered joints not be used in lightning protection ground connections?
为什么防雷接地连接中不能使用焊接点？
A
A soldered joint will likely be destroyed by the heat of a lightning strike
焊接点可能会被雷击的热量破坏
✓ 正确答案
B
Solder flux will prevent a low conductivity connection
焊剂将防止低电导率连接
C
Solder has too high a dielectric constant to provide adequate lightning protection
焊料的介电常数太高，无法提供足够的防雷保护
D
All these choices are correct
所有这些选项都是正确的
#G4C08🔗
Which of the following would reduce RF interference caused by common-mode current on an audio cable?
以下哪一项可以减少音频电缆上共模电流引起的射频干扰？
A
Place a ferrite choke on the cable
在电缆上放置铁氧体扼流圈
✓ 正确答案
B
Connect the center conductor to the shield of all cables to short circuit the RFI signal
将中心导体连接到所有电缆的屏蔽层以短路 RFI 信号
C
Ground the center conductor of the audio cable causing the interference
将造成干扰的音频线中心导体接地
D
Add an additional insulating jacket to the cable
为电缆添加额外的绝缘护套
#G4C09🔗
How can the effects of ground loops be minimized?
如何最大限度地减少接地环路的影响？
A
Connect all ground conductors in series
将所有接地导体串联连接
B
Connect the AC neutral conductor to the ground wire
将交流中性线连接至地线
C
Avoid using lock washers and star washers when making ground connections
进行接地连接时避免使用锁紧垫圈和星形垫圈
D
Bond equipment enclosures together
将设备外壳粘合在一起
✓ 正确答案
#G4C10🔗
What could be a symptom caused by a ground loop in your station’s audio connections?
您电台的音频连接中的接地环路可能会导致什么症状？
A
You receive reports of “ hum ” on your station’s transmitted signal
您收到电台传输信号上的“嗡嗡声”报告
✓ 正确答案
B
The SWR reading for one or more antennas is suddenly very high
一根或多根天线的 SWR 读数突然非常高
C
An item of station equipment starts to draw excessive amounts of current
某站设备开始消耗过量电流
D
You receive reports of harmonic interference from your station
您收到来自您的电台的谐波干扰报告
#G4C11🔗
What technique helps to minimize RF “hot spots” in an amateur station?
什么技术有助于最大限度地减少业余电台中的射频“热点”？
A
Building all equipment in a metal enclosure
将所有设备构建在金属外壳中
B
Using surge suppressor power outlets
使用浪涌抑制器电源插座
C
Bonding all equipment enclosures together
将所有设备外壳粘合在一起
✓ 正确答案
D
Placing low-pass filters on all feed lines
在所有馈电线上放置低通滤波器
#G4C12🔗
Why must all metal enclosures of station equipment be grounded?
为什么车站设备的所有金属外壳必须接地？
A
It prevents a blown fuse in the event of an internal short circuit
它可以防止内部短路时保险丝熔断
B
It prevents signal overload
它可以防止信号过载
C
It ensures that the neutral wire is grounded
确保中性线接地
D
It ensures that hazardous voltages cannot appear on the chassis
确保机箱上不会出现危险电压
✓ 正确答案
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