In high-density environments like stadiums and convention centers, the presence of large crowds significantly impacts Wi-Fi signal propagation.Human bodies, composed mostly of water, absorb and attenuate radio frequency (RF) signals, especially in the 2.4 GHz and 5 GHz bands commonly used by Wi-Fi.This absorption leads to reduced signal strength and potential connectivity issues during events when the venue is filled with people.
Designing a WLAN for such environments requires careful consideration of crowd density and its impact on RF signals.Strategies may include increasing the number of access points (APs), using directional antennas to focus coverage, and conducting site surveys during events to assess real-world performance.
Reference: CWDP-305 Official Study and Reference Guide, Chapter on Designing for Specific Applications

Comprehensive and Detailed Explanation:
Installing antennas on a 70-foot tower involves working at significant heights, which presents safety risks and requires specialized skills. Therefore:
A: Hiring a certified tower installer:It is essential to employ professionals who are certified and trained in tower climbing and installation to ensure compliance with safety regulations and standards, such as those set by OSHA and ANSI.
B: Special antennas that avoid reflections on the tower poles:While antenna placement is important, standard antennas can be used with proper installation techniques to minimize reflections.
C: APs that are designed to operate above 70 feet:Access points are designed to operate within specific environmental conditions, but the height of installation does not typically necessitate special APs.
D: Special RF cables that will not create loss incurred by the metal tower construction:Standard RF cables are designed to function effectively in various installations; however, proper cable selection and installation practices are important to minimize signal loss.
Reference:CWDP-305 Study Guide, Chapter on Advanced Site Surveys - Safety Considerations for Outdoor Installations.