FCC G3B - 无线电波传播

#G3B01🔗

What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation?

通过短路径和长路径传播到达您所在位置的天波信号有什么特征？

Periodic fading approximately every 10 seconds

大约每 10 秒周期性衰落一次

Signal strength increased by 3 dB

信号强度增加 3 dB

The signal might be cancelled causing severe attenuation

信号可能被取消，导致严重衰减

A slightly delayed echo might be heard

可能会听到稍微延迟的回声

✓ 正确答案

#G3B02🔗

What factors affect the MUF?

影响MUF的因素有哪些？

Path distance and location

路径距离和位置

Time of day and season

一天中的时间和季节

Solar radiation and ionospheric disturbances

太阳辐射和电离层扰动

All these choices are correct

所有这些选项都是正确的

✓ 正确答案

#G3B03🔗

Which frequency will have the least attenuation for long-distance skip propagation?

对于长距离跳跃传播，哪个频率的衰减最小？

Just below the MUF

就在 MUF 下方

✓ 正确答案

Just above the LUF

就在 LUF 上方

Just below the critical frequency

刚好低于临界频率

Just above the critical frequency

刚好高于临界频率

#G3B04🔗

Which of the following is a way to determine current propagation on a desired band from your station?

以下哪一项是确定您的电台在所需频段上的当前传播的方法？

Use a network of automated receiving stations on the internet to see where your transmissions are being received

使用互联网上的自动接收站网络来查看您的传输在哪里被接收

✓ 正确答案

Check the A-index

检查A指数

Send a series of dots and listen for echoes

发送一系列点并聆听回声

All these choices are correct

所有这些选项都是正确的

#G3B05🔗

How does the ionosphere affect radio waves with frequencies below the MUF and above the LUF?

电离层如何影响频率低于 MUF 和高于 LUF 的无线电波？

They are refracted back to Earth

它们被折射回地球

✓ 正确答案

They pass through the ionosphere

它们穿过电离层

They are amplified by interaction with the ionosphere

它们通过与电离层的相互作用而被放大

They are refracted and trapped in the ionosphere to circle Earth

它们被折射并被困在电离层中绕地球运行

#G3B06🔗

What usually happens to radio waves with frequencies below the LUF?

频率低于 LUF 的无线电波通常会发生什么？

They are refracted back to Earth

它们被折射回地球

They pass through the ionosphere

它们穿过电离层

They are attenuated before reaching the destination

它们在到达目的地之前就被削弱了

✓ 正确答案

They are refracted and trapped in the ionosphere to circle Earth

它们被折射并被困在电离层中绕地球运行

#G3B07🔗

What does LUF stand for?

LUF 代表什么？

The Lowest Usable Frequency for communications between two specific points

两个特定点之间通信的最低可用频率

✓ 正确答案

Lowest Usable Frequency for communications to any point outside a 100-mile radius

与 100 英里半径以外任何点进行通信的最低可用频率

The Lowest Usable Frequency during a 24-hour period

24小时内最低可用频率

Lowest Usable Frequency during the past 60 minutes

过去 60 分钟内的最低可用频率

#G3B08🔗

What does MUF stand for?

MUF 代表什么？

The Minimum Usable Frequency for communications between two points

两点之间通信的最低可用频率

The Maximum Usable Frequency for communications between two points

两点之间通信的最大可用频率

✓ 正确答案

The Minimum Usable Frequency during a 24-hour period

24小时内的最低可用频率

The Maximum Usable Frequency during a 24-hour period

24小时内最大可用频率

#G3B09🔗

What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the F2 region?

使用 F2 区域一跳通常沿地球表面覆盖的最大距离大约是多少？

180 miles

180 英里

1,200 miles

1,200 英里

2 , 500 miles

2、500英里

✓ 正确答案

12,000 miles

12,000 英里

#G3B10🔗

What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the E region?

使用 E 区域一跳通常沿地球表面覆盖的最大距离大约是多少？

180 miles

180 英里

1 , 200 miles

1、200英里

✓ 正确答案

2,500 miles

2,500 英里

12,000 miles

12,000 英里

#G3B11🔗

What happens to HF propagation when the LUF exceeds the MUF?

当 LUF 超过 MUF 时，HF 传播会发生什么？

Propagation via ordinary skywave communications is not possible over that path

在该路径上不可能通过普通天波通信进行传播

✓ 正确答案

HF communications over the path are enhanced

路径上的高频通信得到增强

Double-hop propagation along the path is more common

沿路径的双跳传播更为常见

Propagation over the path on all HF frequencies is enhanced

所有 HF 频率路径上的传播均得到增强

#G3B12🔗

Which of the following is typical of the lower HF frequencies during the summer?

以下哪项是夏季典型的较低高频频率？

Poor propagation at any time of day

一天中任何时间传播效果不佳

World-wide propagation during daylight hours

白天在世界范围内传播

Heavy distortion on signals due to photon absorption

由于光子吸收导致信号严重失真

High levels of atmospheric noise or static

高水平的大气噪音或静电

✓ 正确答案

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FCC G3B - 无线电波传播

小节 G3B：无线电波传播