Each AP has a specific coverage radius, and placing them too closely can cause interference, while placing them too far apart can create coverage gaps. Aim for an even distribution to ensure seamless roaming and connectivity. Best regards, Tuan 12-13-2018. Here are a few reasons why: By placing your access points in the room, you can limit or avoid entirely both co-channel and adjacent channel interference associated with older, less efficient models. Room installation provides a natural buffer to the signal by using the walls to further reduce. The open ceiling is heavily installed with HVAC and the cable tray is the lowest point which provide the direct LoS between AP and the end users. RE: AP mounting underneath the cable tray Mounting under is definetly better than putting it in the cable tray. This is the power ratio in decibels (dB) of the measured power referenced. While there are many things that can affect wireless local area network (WLAN) operation, the placement of wireless access points (AP) can be one of the most significant factors in performance.