Question
Which of the following is a method for establishing EME contacts?
Answer Options
- A) Time-synchronous transmissions alternating between stations
- B) Storing and forwarding digital messages
- C) Judging optimum transmission times by monitoring beacons reflected from the moon
- D) High-speed CW identification to avoid fading
Correct Answer: A
Explanation
Earth-Moon-Earth (EME) communication is highly sensitive to the timing of transmissions due to the extreme path length and the nature of the available digital modes (like JT65 and Q65). The time delay for the signal to travel to the moon and return is approximately 2.5 seconds, requiring rigid timing coordination between the two stations.
The standard method for establishing an EME contact is time-synchronous transmissions alternating between stations. The operating procedure (known as a schedule) divides a contact period into alternating time slots (e.g., 60 seconds each). One station transmits during the first slot, and the other transmits during the second slot, ensuring their weak signals are not constantly jamming each other.
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