Exam 350-401 topic 1 question 224 discussion

There is obviously a typo here, you cant go to the + range.. Maximum achievable strength is -30dbm. The question should say -75, not 75.

The correct answer is: E: run away because the radio waves reach your device with a power of 31622 W. :D

A is correct SNR = (-75 dBm) - (-90 dBm) = -75 dBm + 90 dBm = 15 dB https://documentation.meraki.com/MR/Wi-Fi_Basics_and_Best_Practices/Signal-to-Noise_Ratio_(SNR)_and_Wireless_Signal_Strength

C: is correct https://www.omnicalculator.com/physics/signal-to-noise-ratio

To calculate the Signal-to-Noise Ratio (SNR), we need to convert the signal and noise power from dBm to linear scale (watts) and then use the SNR equation: SNR (dB) = 10 * log10(signal power / noise power) Given: Noise floor = -90 dBm Signal strength = 75 dBm First, let's convert the signal and noise power to watts: Signal Power (W) = 10^((Signal Strength (dBm) - 30) / 10) Signal Power (W) = 10^((75 - 30) / 10) Signal Power (W) = 10^4.5 Signal Power (W) = 31,622.7766 W Noise Power (W) = 10^((Noise Floor (dBm) - 30) / 10) Noise Power (W) = 10^((-90 - 30) / 10) Noise Power (W) = 10^-12 Noise Power (W) = 0.000000000001 W Now, let's calculate the SNR in dB: SNR (dB) = 10 * log10(signal power / noise power) SNR (dB) = 10 * log10(31,622.7766 / 0.000000000001) SNR (dB) = 10 * log10(31,622,776,600,000,000) SNR (dB) = 10 * 16.5 SNR (dB) = 165 Therefore, the SNR is 165 dB. The correct answer is C.

What is גˆ’ supposed to mean?

The example might be taken from this site: https://documentation.meraki.com/MR/Wi-Fi_Basics_and_Best_Practices/Signal-to-Noise_Ratio_(SNR)_and_Wireless_Signal_Strength "For example, if a client device's radio receives a signal at -75 dBm, and the noise floor is -90 dBm, then the effective SNR is 15 dB. This would then reflect as a signal strength of 15 dB for this wireless connection. "

There is typo coz the the answer shud be 165

Asymptote is wrong, A is correct answer

C SNR = signal strength in dBm - noise 75 - (-90) = 165 if a client device's radio receives a signal at -75 dBm, and the noise floor is -90 dBm, then the effective SNR is 15 dB. This would then reflect as a signal strength of 15 dB for this wireless connection. Reference: https://documentation.meraki.com/MR/Wi-Fi_Basics_and_Best_Practices/Signal-to-Noise_Ratio_(SNR)_and_Wireless_Signal_Strength#:~:text=if%20a%20client%20device%27s%20radio%20receives%20a%20signal%20at%20%2D75%20dBm%2C%20and%20the%20noise%20floor%20is%20%2D90%20dBm%2C%20then%20the%20effective%20SNR%20is%2015%20dB.%C2%A0This%20would%20then%20reflect%20as%20a%20signal%20strength%20of%2015%20dB%20for%20this%20wireless%20connection.%C2%A0

90-75=15