Deep Dive: G9C08
The correct answer is D: The direction of maximum radiated field strength from the antenna. What is meant by the 'main lobe' of a directive antenna is the direction of maximum radiated field strength from the antenna. The main lobe is where the antenna radiates most strongly. For amateur radio operators, this is the primary radiation direction. Understanding this helps when using directional antennas.
Why Other Answers Are Wrong
Option A: Incorrect. Main lobe isn't maximum vertical angle of radiation - it's the direction of maximum field strength, not just angle. Vertical angle isn't the definition. Option B: Incorrect. Main lobe isn't point of maximum current - current and radiation pattern are different. Maximum current isn't the main lobe. Option C: Incorrect. Main lobe isn't maximum voltage standing wave point - VSWR and radiation pattern are different. VSWR point isn't the main lobe.
Exam Tip
Main lobe = direction of maximum radiated field strength. Think 'M'ain 'L'obe = 'M'aximum 'L'ight (radiation) direction. The main lobe is where the antenna radiates most strongly. Not vertical angle, not maximum current, not VSWR point - just direction of maximum field strength.
Memory Aid
Main lobe = direction of maximum radiated field strength. Think 'M'ain 'L'obe = 'M'aximum 'L'ight direction. The main lobe is where the antenna radiates most strongly. Primary radiation direction of directive antennas.
Real-World Example
A directive antenna (like a Yagi): The main lobe is the direction where the antenna radiates most strongly (maximum field strength). For a Yagi pointing east, the main lobe is toward the east - that's where maximum radiation occurs. This is the primary radiation direction - the main lobe.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G9C
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 G9C topic.