CWNA-109 CERTIFIED
WIRELESS NETWORK
ADMINISTRATOR
PRACTICE EXAM
Question 1: A WLAN transmitter is measured at 50 mW. Using the rule of 10s and 3s, approximately what is its power in dBm?
Choices:
1) 14 dBm 2) 17 dBm 3) 20 dBm 4) 23 dBm
Correct Answer: 17 dBm
Explanation: 50 mW is approximately 17 dBm. Starting at 100 mW = 20 dBm, halving the power to 50 mW subtracts 3 dB, giving 17 dBm.Page 1
Question 2: An access point transmits at 17 dBm through a cable with 2 dB of loss to an antenna with 5 dBi of gain. Ignoring other losses, what is the approximate EIRP?
Choices:
1) 20 dBm 2) 14 dBm 3) 17 dBm 4) 22 dBm
Correct Answer: 20 dBm
Explanation: EIRP is transmitter power minus cable loss plus antenna gain: 17 dBm - 2 dB + 5 dBi = 20 dBm.Question 3: At a client location the received signal is -62 dBm and the noise �oor is -92 dBm. What is the signal-to-noise ratio?
Choices:
1) 30 dB 2) 20 dB 3) -30 dB 4) 154 dB
Correct Answer: 30 dB
Explanation: SNR is the di�erence between received signal level and noise �oor: -62 dBm - (-92 dBm) = 30 dB.Page 2
Question 4: Two otherwise identical point-to-point links operate over the same
distance, one at 2.4 GHz and one at 5 GHz. In free space, which link has greater free-space path loss?
Choices:
1) The 2.4 GHz link 2) They have identical path loss 3) The 5 GHz link 4) Path loss depends only on transmit power
Correct Answer: The 5 GHz link
Explanation: Free-space path loss increases with frequency when distance is held constant, so the 5 GHz link experiences more FSPL than the 2.4 GHz link.Question 5: A client receives multiple delayed copies of the same RF transmission because the signal re�ects from walls and metal surfaces. What phenomenon is occurring?
Choices:
1) Absorption 2) Refraction 3) Ampli�cation 4) Multipath
Correct Answer: Multipath
Explanation: Multipath occurs when re�ected or otherwise redirected copies of the same signal arrive at a receiver over di�erent paths and at di�erent times.Page 3