CWS CWS Site Survey Fundamentals 2 — Questions and Answers
Question 1: During a passive wireless site survey, which action best describes what the surveyor does?
- Associates a client device to each AP and measures throughput
- Listens to existing RF traffic without transmitting probe frames (Correct answer)
- Deploys temporary APs and measures coverage overlap
- Sends ICMP pings to measure round-trip latency
Correct answer: Listens to existing RF traffic without transmitting probe frames
A passive survey involves only listening to existing RF transmissions without the survey device transmitting, allowing unobtrusive measurement of existing signal levels.
Question 2: What is the primary purpose of measuring the Signal-to-Noise Ratio (SNR) during a site survey?
- To calculate the exact transmit power of nearby APs
- To determine how well a signal can be distinguished from background RF noise (Correct answer)
- To count the number of client devices associated to each AP
- To verify the physical cable connections to each access point
Correct answer: To determine how well a signal can be distinguished from background RF noise
SNR quantifies the difference between the desired signal strength and the ambient noise floor, directly predicting data rate and connection reliability.
Question 3: A site surveyor notices the noise floor in a warehouse is -85 dBm. An AP signal reads -75 dBm. What is the SNR?
- 10 dB (Correct answer)
- 160 dB
- -160 dB
- -10 dB
Correct answer: 10 dB
SNR = Signal – Noise = -75 dBm – (-85 dBm) = 10 dB.
Question 4: Which document should a CWS candidate review BEFORE conducting an on-site survey to understand areas that may be off-limits or require escorts?
- The IEEE 802.11 amendment list
- A site security policy or facility access agreement (Correct answer)
- The manufacturer's AP datasheet
- The ISP service-level agreement
Correct answer: A site security policy or facility access agreement
A site security policy or facility access agreement identifies restricted zones, required escorts, and safety rules that must be followed during any physical survey.
Question 5: Which type of site survey uses software to model RF propagation before any hardware is installed?
- Active survey
- Passive survey
- Predictive (RF modeling) survey (Correct answer)
- Manual walk-test survey
Correct answer: Predictive (RF modeling) survey
A predictive survey uses floor plan data and propagation models in software to estimate coverage without deploying physical hardware.
Question 6: When performing a site survey in a building with multiple floors, what critical factor must be accounted for regarding RF propagation?
- Signals only travel horizontally and never penetrate floors
- Inter-floor signal bleed can cause co-channel interference between vertically adjacent APs (Correct answer)
- Each floor operates on a completely isolated RF spectrum by regulation
- Vertical signal propagation always doubles the path loss compared to horizontal
Correct answer: Inter-floor signal bleed can cause co-channel interference between vertically adjacent APs
RF signals pass through floors and ceilings, so APs on adjacent floors on the same channel can interfere with each other, requiring 3D channel planning.
Question 7: What is the recommended minimum RSSI value for basic Voice over Wi-Fi (VoWiFi) coverage in most enterprise deployments?
- -85 dBm
- -70 dBm (Correct answer)
- -55 dBm
- -40 dBm
Correct answer: -70 dBm
Voice applications typically require a minimum RSSI of -67 to -70 dBm to maintain adequate SNR and low packet loss for acceptable call quality.
CWS CWS Site Survey Fundamentals 2
During a passive wireless site survey, which action best describes what the surveyor does?