E3: Radio Wave Propagation
Subelement E3 covers advanced radio wave propagation — the physical mechanisms that determine how and where amateur radio signals travel. This subelement addresses three groups: electromagnetic wave fundamentals and specialized propagation modes (EME, meteor scatter, tropospheric ducting, aurora, and circular polarization); advanced ionospheric propagation including transequatorial propagation, long-path, chordal hop, sporadic-E, and ground wave; and space weather effects on propagation including solar indices, the interplanetary magnetic field, and propagation prediction tools.
The Extra exam draws three questions from E3. Each group contributes one question. Mastering the specific conditions, distances, frequencies, and physical causes for each propagation mode is essential.
Study These Topics
E3A: Specialized Propagation
EME geometry and libration fading, electromagnetic wave structure, meteor scatter in the E region, tropospheric ducting over water, auroral propagation and CW, MUF and darkness, circular polarization.
Study E3AE3B: Advanced Propagation Modes
Transequatorial propagation (TEP) distance and timing, long-path on 40m/20m, ordinary and extraordinary waves, chordal-hop mechanics, sporadic-E at solstices, ground-wave polarization and frequency effects.
Study E3BE3C: Propagation Prediction and Space Weather
Solar flares and blackouts, A-index and K-index, Bz orientation, auroral oval absorption, VHF/UHF radio horizon, solar flare classes, geomagnetic storm scales, VOACAP, 304A solar parameter.
Study E3CE3A: Specialized Propagation →
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