Deep Dive: G3A02
The correct answer is B: It disrupts signals on lower frequencies more than those on higher frequencies. The effect of a sudden ionospheric disturbance (SID) on daytime ionospheric propagation is that it disrupts signals on lower frequencies more than those on higher frequencies. SIDs are caused by solar flares that increase D-layer absorption, which affects lower frequencies more. For amateur radio operators, this means lower bands (160m, 80m, 40m) are more affected than higher bands. Understanding this helps explain SID effects.
Why Other Answers Are Wrong
Option A: Incorrect. SIDs don't enhance propagation - they disrupt it. SIDs cause increased absorption, not enhancement. Option C: Incorrect. SIDs don't disrupt satellite communications more - they affect ionospheric propagation, not satellite paths. Satellite communications use different paths. Option D: Incorrect. SIDs affect daytime propagation, not just night side - they're caused by solar flares that affect the sunlit side of Earth.
Exam Tip
SID effect = disrupts lower frequencies more than higher. Think 'S'ID = 'S'olar 'I'onospheric 'D'isturbance disrupts 'L'ower frequencies 'M'ore. D-layer absorption from solar flares affects lower frequencies more severely. Not enhancement, not satellites, not just night side.
Memory Aid
SID effect = disrupts lower frequencies more than higher. Think 'S'ID = 'S'olar 'I'onospheric 'D'isturbance disrupts 'L'ower frequencies. D-layer absorption from solar flares affects lower frequencies more. Key SID characteristic.
Real-World Example
A solar flare causes a sudden ionospheric disturbance. The D-layer absorption increases, disrupting propagation. Lower bands (80m, 40m) are severely affected, while higher bands (20m, 15m) may still work. The increased absorption affects lower frequencies more because they're more dependent on ionospheric propagation.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G3A
Reference: 2023-2027 Question Pool · G3 - Radio Wave Propagation
Key Concepts
Verified Content
Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G3A topic.