Question
What is link margin?
Answer Options
- A) The opposite of fade margin
- B) The difference between received power level and minimum required signal level at the input to the receiver
- C) Transmit power minus receiver sensitivity
- D) Receiver sensitivity plus 3 dB
Correct Answer: B
Explanation
Link margin is the final, crucial metric derived from a link budget calculation. It represents the system’s safety net—the cushion between the predicted performance and the minimum required performance.
Link margin is defined as the difference between the received power level (calculated via the link budget) and the minimum required signal level at the input to the receiver (known as receiver sensitivity). A positive link margin indicates a robust link that can tolerate degradation (like fading or rain loss), whereas a zero or negative margin indicates an unreliable or failed link.
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