Deep Dive: G9D03
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.
Why Other Answers 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.
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 Example
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.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G9D
Reference: 2023-2027 Question Pool · G9 - Antennas and Feed Lines
Key Concepts
Verified Content
Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G9D topic.