Deep Dive: E3C03
The correct answer is B: Through the auroral oval. Which of the following signal paths is most likely to experience high levels of absorption when the A-index or K-index is elevated is through the auroral oval. Auroral paths experience high absorption during geomagnetic storms. For amateur radio operators, this is important for understanding propagation during storms. Understanding this helps when operating during disturbed conditions.
Why Other Answers Are Wrong
Option A (Transequatorial): Incorrect. Transequatorial paths don't experience high absorption - auroral oval paths do. Transequatorial isn't the path. Option C (Sporadic-E): Incorrect. Sporadic-E paths don't experience high absorption - auroral oval paths do. Sporadic-E isn't the path. Option D (NVIS): Incorrect. NVIS paths don't experience high absorption - auroral oval paths do. NVIS isn't the path.
Exam Tip
High absorption path when A/K elevated = through auroral oval. Think 'A'/'K' 'E'levated = 'A'uroral 'E'xtreme absorption. Auroral paths experience high absorption during geomagnetic storms. Not transequatorial, not sporadic-E, not NVIS - just auroral oval.
Memory Aid
High absorption path when A/K elevated = through auroral oval. Think 'A'/'K' 'E'levated = 'A'uroral absorption. Auroral paths experience high absorption during geomagnetic storms. Important for understanding propagation during storms.
Real-World Example
When A-index or K-index is elevated: Signal paths through the auroral oval experience high levels of absorption. The auroral oval is the region where aurora occurs, and during geomagnetic storms, this region has high ionization that absorbs signals. Other paths (transequatorial, sporadic-E, NVIS) don't experience this high absorption. This is the path - through the auroral oval.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E3C
Reference: 2024-2028 Question Pool · E3 - Radio Wave Propagation
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E3C topic.