Question
Which of the following is typical of the lower HF frequencies during the summer?
Answer Options
- A) Poor propagation at any time of day
- B) World-wide propagation during daylight hours
- C) Heavy distortion on signals due to photon absorption
- D) High levels of atmospheric noise or static
Correct Answer: D
Explanation
The lower HF bands, such as 80 and 40 meters, are highly susceptible to atmospheric noise, or static, often referred to as QRN. During the summer months, electrical storm activity is much higher, and the resulting lightning discharges create broadband static pulses that severely degrade reception on these lower frequencies.
This phenomenon is characterized by high levels of atmospheric noise or static. While the lower bands are always affected by atmospheric noise, the summer season, with its increased thunderstorm activity, makes the lower frequencies particularly challenging for reliable communication.
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