350-401 · Question #576
If a client's radio device receives a signal strength of -67 dBm and the noise floor is -85 dBm, what is the SNR value?
The correct answer is C. 18 dB. SNR Calculation Explained Signal-to-Noise Ratio (SNR) is calculated by subtracting the noise floor from the received signal strength: SNR = Signal − Noise Floor = −67 dBm − (−85 dBm) = 18 dB, making C (18 dB) correct. Options A (15 dB) and B (16 dB) are simply incorrect arithmeti
Question
If a client's radio device receives a signal strength of -67 dBm and the noise floor is -85 dBm, what is the SNR value?
Options
- A15 dB
- B16 dB
- C18 dB
- D20 dB
How the community answered
(56 responses)- A7% (4)
- B4% (2)
- C71% (40)
- D18% (10)
Explanation
SNR Calculation Explained
Signal-to-Noise Ratio (SNR) is calculated by subtracting the noise floor from the received signal strength: SNR = Signal − Noise Floor = −67 dBm − (−85 dBm) = 18 dB, making C (18 dB) correct. Options A (15 dB) and B (16 dB) are simply incorrect arithmetic results that may result from miscalculating the subtraction of negative numbers. Option D (20 dB) is a common distractor, as it represents a "round number" that test-takers might guess, but it doesn't reflect the actual math.
Memory Tip: When subtracting a negative number, remember "minus a minus = plus" - so −67 − (−85) becomes −67 + 85 = 18. Think of it as: how far apart are the two values on the number line? Count the distance between −67 and −85, which is 18 units.
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