Question
Which is generally true for 160- and 80-meter receiving antennas?
Answer Options
- A) Atmospheric noise is so high that directivity is much more important than losses
- B) They must be erected at least 1/2 wavelength above the ground to attain good directivity
- C) Low loss coax transmission line is essential for good performance
- D) All these choices are correct
Correct Answer: A
Explanation
The 160-meter and 80-meter bands are in the MF and low HF region, where external noise sources—specifically atmospheric noise (static from thunderstorms worldwide) and man-made noise—are extremely high. In this noise-limited environment, the goal is often not to maximize gain, but to maximize the signal-to-noise ratio by eliminating localized noise.
Since the external noise floor is so high, maximizing the sensitivity of the receiver is less critical than rejecting noise from specific directions. Therefore, it is generally true that atmospheric noise is so high that directivity is much more important than losses. Low-loss transmission lines, for example, matter less than a directional receiving antenna (like a Beverage or a loop) that can null out local interference and unwanted noise.
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