CWS CWS Site Survey Fundamentals 3 — Questions and Answers
Question 1: In Wi-Fi site surveys, what does the term 'roaming threshold' refer to?
- The maximum number of clients an AP can support simultaneously
- The RSSI level at which a client device begins scanning for a better AP (Correct answer)
- The distance limit between two APs before a new AP must be added
- The regulatory transmit power ceiling for a given country
Correct answer: The RSSI level at which a client device begins scanning for a better AP
The roaming threshold is the signal strength value at which a client starts scanning for a stronger AP, directly affecting seamless handoff between APs.
Question 2: A surveyor finds significant co-channel interference (CCI) in the 2.4 GHz band. Which is the BEST corrective action?
- Increase transmit power on all APs to overpower the interference
- Migrate affected devices to 5 GHz or 6 GHz bands with more non-overlapping channels (Correct answer)
- Switch all APs to use 40 MHz channel width in 2.4 GHz
- Reboot all APs simultaneously to reset their channel assignments
Correct answer: Migrate affected devices to 5 GHz or 6 GHz bands with more non-overlapping channels
The 2.4 GHz band offers only 3 non-overlapping 20 MHz channels, so migrating to 5 GHz or 6 GHz—which offer many more non-overlapping channels—is the most effective CCI mitigation.
Question 3: Which site survey tool feature allows a surveyor to capture and visualize RF signal strength overlaid on a floor plan?
- Packet capture (sniffer) mode
- Heatmap generation (Correct answer)
- SNMP polling dashboard
- Spectrum analyzer FFT plot
Correct answer: Heatmap generation
Heatmap generation in site survey software plots measured RSSI values at GPS/floor-plan coordinates, producing a color-coded coverage map.
Question 4: What is the significance of the 'free path loss' formula during a site survey?
- It calculates the maximum client association rate at a given distance
- It estimates how much RF signal attenuates over distance in open space (Correct answer)
- It determines the legal maximum EIRP for a given antenna gain
- It defines the minimum cable length between AP and switch
Correct answer: It estimates how much RF signal attenuates over distance in open space
Free-space path loss (FSPL) quantifies signal attenuation due to distance alone, giving surveyors a baseline before accounting for obstacles.
Question 5: During a site survey, a surveyor discovers a strong non-Wi-Fi interference source around 2.45 GHz. Which tool would BEST identify this interferer?
- Wi-Fi protocol analyzer
- Spectrum analyzer (Correct answer)
- Cable continuity tester
- SNMP network management system
Correct answer: Spectrum analyzer
A spectrum analyzer detects all RF energy in a band—including non-802.11 sources like microwaves or Bluetooth—whereas a Wi-Fi analyzer only sees 802.11 frames.
Question 6: Why is it important to conduct a site survey using the same client devices that will actually be used in production?
- All Wi-Fi clients are identical, so device choice has no impact on survey results
- Different client devices have varying antenna designs, receiver sensitivities, and roaming behaviors (Correct answer)
- Regulations require using end-user devices for all commercial site surveys
- Enterprise APs reject connections from survey laptops by default
Correct answer: Different client devices have varying antenna designs, receiver sensitivities, and roaming behaviors
Client device capability varies widely in antenna gain, MIMO chains, and roaming aggressiveness, meaning survey results with one device may not reflect real-world performance with another.
Question 7: What does EIRP stand for in the context of wireless site surveys?
- Effective Interference Reduction Protocol
- Equivalent Isotropically Radiated Power (Correct answer)
- External Interference RF Percentage
- Enhanced Integrated Radio Performance
Correct answer: Equivalent Isotropically Radiated Power
EIRP (Equivalent Isotropically Radiated Power) is the total power radiated by an antenna system, calculated as transmit power plus antenna gain minus cable losses.
CWS CWS Site Survey Fundamentals 3
In Wi-Fi site surveys, what does the term 'roaming threshold' refer to?