Question
Which of the following digital modes is designed for EME communications?
Answer Options
- A) MSK144
- B) PACTOR III
- C) WSPR
- D) Q65
Correct Answer: D
Explanation
Earth-Moon-Earth (EME) or ‘moonbounce’ communications involves transmitting a signal that travels approximately 500,000 miles to the Moon and back, resulting in massive path loss. This mode is the pinnacle of weak-signal operation, often requiring high power, large antennas, and extremely sensitive receiving techniques. The contacts are usually characterized by long, precisely timed sequences of transmissions.
Q65 is a weak-signal digital mode developed by K1JT specifically to be robust against the challenging propagation characteristics of EME, such as deep fading, Faraday rotation, and high Doppler shift. It is optimized to extract data from signals buried far below the noise floor, offering superior performance compared to earlier EME modes like JT65.
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