In which direction is the maximum radiation from a VHF/UHF “halo” antenna?
The correct answer is C: Omnidirectional in the plane of the halo. The direction of maximum radiation from a VHF/UHF 'halo' antenna is omnidirectional in the plane of the halo. Halo antennas (circular loop) radiate equally in all directions in the plane of the loop. For amateur radio operators, this is ideal for omnidirectional coverage. Understanding this helps when using halo antennas.
Exam Tip
Halo antenna radiation = omnidirectional in plane of halo. Think 'H'alo = 'H'orizontal 'O'mnidirectional. Halo antennas (circular loop) radiate equally in all directions in the plane of the loop. Not broadside, not opposite feed point, not same side - just omnidirectional in plane.
Memory Aid
"Halo antenna radiation = omnidirectional in plane of halo. Think 'H'alo = 'O'mnidirectional. Halo antennas (circular loop) radiate equally in all directions in the plane of the loop. Ideal for omnidirectional coverage."
Real-World Application
A VHF/UHF halo antenna: The circular loop radiates equally in all directions in the plane of the halo (horizontal plane). Viewed from above, it's omnidirectional - ideal for making contacts in all directions without needing to rotate. This is the radiation pattern - omnidirectional in the plane of the halo.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Maximum radiation isn't broadside to the plane - halo radiates in the plane, not broadside. Broadside is wrong.
Option B: Incorrect. Maximum radiation isn't opposite the feed point - halo is omnidirectional in the plane, not directional. Opposite feed point is wrong.
Option D: Incorrect. Maximum radiation isn't on the same side as the feed point - halo is omnidirectional, not directional. Same side is wrong.
题目解析
The correct answer is C: Omnidirectional in the plane of the halo. The direction of maximum radiation from a VHF/UHF 'halo' antenna is omnidirectional in the plane of the halo. Halo antennas (circular loop) radiate equally in all directions in the plane of the loop. For amateur radio operators, this is ideal for omnidirectional coverage. Understanding this helps when using halo antennas.
考试技巧
Halo antenna radiation = omnidirectional in plane of halo. Think 'H'alo = 'H'orizontal 'O'mnidirectional. Halo antennas (circular loop) radiate equally in all directions in the plane of the loop. Not broadside, not opposite feed point, not same side - just omnidirectional in plane.
记忆口诀
Halo antenna radiation = omnidirectional in plane of halo. Think 'H'alo = 'O'mnidirectional. Halo antennas (circular loop) radiate equally in all directions in the plane of the loop. Ideal for omnidirectional coverage.
实际应用示例
A VHF/UHF halo antenna: The circular loop radiates equally in all directions in the plane of the halo (horizontal plane). Viewed from above, it's omnidirectional - ideal for making contacts in all directions without needing to rotate. This is the radiation pattern - omnidirectional in the plane of the halo.
错误选项分析
Option A: Incorrect. Maximum radiation isn't broadside to the plane - halo radiates in the plane, not broadside. Broadside is wrong. Option B: Incorrect. Maximum radiation isn't opposite the feed point - halo is omnidirectional in the plane, not directional. Opposite feed point is wrong. Option D: Incorrect. Maximum radiation isn't on the same side as the feed point - halo is omnidirectional, not directional. Same side is wrong.
知识点
Halo antenna, VHF/UHF, Omnidirectional, Plane of the halo
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.