L1 - What is coastal effect? [ADF system]

Question

BlackTom AI · Accepted Answer

Question restatement: L1 - What is coastal effect? [ADF system]

Answer options:
1) ADF bearing information can only be received from in front of aircraft
2) Hard iron effects in aircraft result in ADF bearing errors
3) Errors introduced in the ADF signal because of p-static and electrical interference
4) Bending of the ADF signal when passing from land to water

Option 1 analysis: This statement claims ADF bearing information is only available from in front of the aircraft. In reality, an ADF system uses a loop antenna and senses a bearing to a non-directional beacon (NDB) from all directions around the aircraft. It is not limited to the front hemisphere. Therefore, this option is incorrect because it misstates how ADF bearing reception works.

Option 2 analysis: “Hard iron effects in aircraft result in ADF bearing errors.” While hard iron distortions can affect magnetic compasses by shifting the local field, ADF systems rely on RF reception and a loop antenna to determine bearing to the NDB. Although aircraft metal can influence radio signals in some ways, this statement more accurately describes compass errors or magnetometer effects, not the coastal effect. Thus, this option is incorrect in the context of coastal effect.

Option 3 analysis: “Errors introduced in the ADF signal because of p-static and electrical interference.” Precipitating p-static and general electrical interference can degrade radio navigation signals, but this describes broad RF noise/interference rather than the specific coastal effect phenomenon. Therefore, this option does not describe the coastal effect and is incorrect as the primary cause of coastal effect.

Option 4 analysis: “Bending of the ADF signal when passing from land to water.” This aligns with the recognized coastal effect: when the aircraft crosses the coastline, the contrast in conductivity and ground impedance between land and sea modifies the ADF signal path, causing the bearing indication to bend or deflect from its true line to the beacon. This option accurately captures the specific phenomenon described by coastal effect and is therefore correct.

Summary of reasoning across options: The first three statements describe general antenna reception, magnetic/iron-related errors, and RF interference—which are not the defined coastal effect. The fourth option explicitly identifies the characteristic coastal effect as the bending of the ADF signal at the land–water boundary, which matches standard aviation navigation explanations for this phenomenon.

L1 - What is coastal effect? [ADF system]多项选择题

类似问题

[Week 3 HF Advantages] - What is the primary advantage of using HF over VHF for communication?

[Week 2 VHF Range] - What is the maximum effective range of a typical VHF radio under ideal atmospheric conditions?

[Week 2 VHF Range] - What is the maximum effective range of a typical VHF radio under ideal atmospheric conditions?

关于VHF传播，以下正确的选项是：

What was the world's first widely adopted biodiversity policy?

The aim of the Paris Agreement is to ensure that the earth’s preindustrial temperature is not exceeded by more than º Celsius.

The IPCC's mission is to Blank ______.

Why have most international agreements for environmental protection been based on the honor system?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单