When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?
The correct answer is D: It should be at least one wavelength long. When constructing a Beverage antenna, to achieve good performance at the desired frequency, it should be at least one wavelength long. Longer Beverage antennas generally perform better.
Beverage antennas are long-wire receiving antennas, typically several wavelengths long. They work best when they're at least one wavelength long, and longer is generally better. A Beverage antenna that's too short (less than 1/4 wavelength) won't work well. The antenna needs sufficient length to develop the traveling wave characteristics that make Beverages effective for low-angle reception. Typical Beverage antennas are 1 to 4 wavelengths long, with longer antennas providing better directivity and lower-angle response. The length is a critical design parameter for Beverage antenna performance.
Exam Tip
Beverage antenna length = At least one wavelength. Remember: A Beverage antenna should be at least one wavelength long for good performance. Longer is generally better for directivity and low-angle reception.
Memory Aid
"**B**everage **A**ntenna = **A**t **L**east **1**λ (think 'BA = AL1λ')"
Real-World Application
You're building a Beverage antenna for 160 meters (1.8 MHz). The wavelength is about 167 meters. You make your Beverage at least one wavelength long (maybe 200-300 meters). This length allows the antenna to develop proper traveling wave characteristics for effective low-angle reception. A shorter antenna wouldn't work as well.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. A Beverage antenna longer than 1/4 wavelength works better. The minimum is one wavelength, not a maximum of 1/4 wavelength.
Option B: Incorrect. Beverage antennas don't need to be mounted more than 1 wavelength above ground. They're typically mounted low (a few feet) above ground.
Option C: Incorrect. Beverage antennas are linear (wire) antennas, not four-sided loops. They're long wires, not loops.
题目解析
The correct answer is D: It should be at least one wavelength long. When constructing a Beverage antenna, to achieve good performance at the desired frequency, it should be at least one wavelength long. Longer Beverage antennas generally perform better. Beverage antennas are long-wire receiving antennas, typically several wavelengths long. They work best when they're at least one wavelength long, and longer is generally better. A Beverage antenna that's too short (less than 1/4 wavelength) won't work well. The antenna needs sufficient length to develop the traveling wave characteristics that make Beverages effective for low-angle reception. Typical Beverage antennas are 1 to 4 wavelengths long, with longer antennas providing better directivity and lower-angle response. The length is a critical design parameter for Beverage antenna performance.
考试技巧
Beverage antenna length = At least one wavelength. Remember: A Beverage antenna should be at least one wavelength long for good performance. Longer is generally better for directivity and low-angle reception.
记忆口诀
**B**everage **A**ntenna = **A**t **L**east **1**λ (think 'BA = AL1λ')
实际应用示例
You're building a Beverage antenna for 160 meters (1.8 MHz). The wavelength is about 167 meters. You make your Beverage at least one wavelength long (maybe 200-300 meters). This length allows the antenna to develop proper traveling wave characteristics for effective low-angle reception. A shorter antenna wouldn't work as well.
错误选项分析
Option A: Incorrect. A Beverage antenna longer than 1/4 wavelength works better. The minimum is one wavelength, not a maximum of 1/4 wavelength. Option B: Incorrect. Beverage antennas don't need to be mounted more than 1 wavelength above ground. They're typically mounted low (a few feet) above ground. Option C: Incorrect. Beverage antennas are linear (wire) antennas, not four-sided loops. They're long wires, not loops.
知识点
Beverage antenna, Antenna length, One wavelength, Receiving antenna
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.