Two scanners sit on the same access point with the same noise floor. One shows a received signal of -45 dBm and the other shows -75 dBm. Which statement is correct?
Select an answer to reveal the explanation.
Short Explanation
A less negative dBm reading is a stronger signal. Your scanner at -45 dBm is well above the one at -75 dBm, so it has more room above the same noise. Association only means both cleared the minimum, not that they are equal.
Full Explanation
Received signal in dBm is stronger as the number gets closer to zero. -45 dBm is 30 dB stronger than -75 dBm. With the same noise floor, the stronger scanner has a larger SNR and more fade margin. Both can be associated and still be nowhere near equal. Association means each scanner met the minimum the BSS requires. It does not flatten two readings that are 30 dB apart. A more negative dBm value is weaker, not stronger. Reading -75 as larger than -45 reverses the scale. The noise floor is a property of the channel at that spot, not a number that rises because a scanner is closer. The closer scanner should show a stronger signal, which is what -45 dBm is, and the question says the noise floor is the same. Exam caveat: margin still depends on the rate. A client that is fine at a low rate can fail a high mandatory rate even at -45 dBm if the noise is terrible, but here the noise is the same and the signals are not. Operational check: stand with both scanners, read signal and noise, and confirm the -45 dBm unit holds a higher rate.