T3C04: Sporadic E: Of the following types of propagation is

Q: Which of the following types of propagation is most commonly associated with occasional strong signals on the 10, 6, and 2 meter bands from beyond the radio horizon?

The correct answer is B: Sporadic E. The correct answer is B: Sporadic E. Sporadic E (Es) is the propagation mode most commonly associated with occasional strong signals on the 10, 6, and 2 meter bands from beyond the radio horizon. Sporadic E creates temporary 'clouds' of intense ionization in the E layer of the ionosphere that can refract VHF signals. Sporadic E is most common during summer months and can provide contacts on 10 meters, 6 meters, and sometimes even 2 meters over distances of 500-1500 miles. The 'sporadic' name comes from its unpredictable nature - it appears and disappears without much warning. When sporadic E is active, these bands can 'open up' and provide excellent long-distance contacts that aren't normally possible on VHF.

Updated: Dec 9, 2025 | Source: 2022-2026 Question Pool | Topic: T3C

T3C04T3C

Which of the following types of propagation is most commonly associated with occasional strong signals on the 10, 6, and 2 meter bands from beyond the radio horizon?

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Deep Dive: T3C04

The correct answer is B: Sporadic E. Sporadic E (Es) is the propagation mode most commonly associated with occasional strong signals on the 10, 6, and 2 meter bands from beyond the radio horizon. Sporadic E creates temporary 'clouds' of intense ionization in the E layer of the ionosphere that can refract VHF signals. Sporadic E is most common during summer months and can provide contacts on 10 meters, 6 meters, and sometimes even 2 meters over distances of 500-1500 miles. The 'sporadic' name comes from its unpredictable nature - it appears and disappears without much warning. When sporadic E is active, these bands can 'open up' and provide excellent long-distance contacts that aren't normally possible on VHF.

Why Other Answers Are Wrong

Option A: Incorrect. Backscatter is less common and typically provides shorter distances than sporadic E on these bands. Option C: Incorrect. D region absorption actually prevents propagation, it doesn't enable long-distance contacts. Option D: Incorrect. Gray-line propagation is more relevant to HF bands, not the primary mode for 10/6/2 meter long-distance contacts.

Exam Tip

10/6/2 meter long-distance = Sporadic E. Remember: Sporadic E is the most common propagation mode that provides strong signals on 10, 6, and 2 meters from beyond the radio horizon.

Memory Aid

**S**poradic **E** = **S**trong **E**xtended range (think 'SE = SE' = Strong Extended range)

Real-World Example

During a summer afternoon, you're monitoring 6 meters and suddenly hear stations from 800 miles away coming in strong. This is sporadic E - temporary intense ionization in the E layer is refracting 6-meter signals, allowing contacts far beyond normal range. The opening might last minutes or hours, then disappear. This is the 'magic' of 6 meters and why it's called the 'magic band' - sporadic E can make the impossible possible.

Source & Coverage

Question Pool: 2022-2026 Question Pool

Subelement: T3C

Reference: FCC Part 97.3

Key Concepts

Sporadic E VHF propagation 10/6/2 meters Beyond horizon

Verified Content

Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T3C topic.