What is Site Survey?

Understanding Site Survey

A site survey is an on-site assessment of a physical location to gather the data needed to design, secure, or audit infrastructure, most commonly wireless networks and physical security controls. It documents the layout, RF coverage and interference, access points, entry points, and existing safeguards so deployments perform well and vulnerabilities are identified.

For wireless, surveys come in three forms: a predictive survey models coverage from floor plans and materials before installation; a passive survey listens to existing RF to map signal strength, channel use, and rogue access points; and an active survey associates with the network to measure real throughput, retransmissions, and roaming. Tools like Ekahau or NetSpot produce heat maps that guide AP placement, channel planning, and power levels. Physical security surveys instead inventory doors, locks, cameras, lighting, and access-control coverage.

This matters for security as well as performance. A poorly surveyed wireless deployment can leak signal far beyond the building's walls, letting an attacker in the parking lot capture traffic or attempt association, while coverage gaps invite users onto rogue or evil-twin access points. Passive surveys also detect unauthorized APs and interference. On the physical side, surveys reveal unmonitored doors, camera blind spots, and tailgating risks that controls must address before they can be relied upon.

For example, before deploying Wi-Fi in a new clinic handling patient data, an engineer runs a predictive survey, then validates with a passive and active walk-through using a heat-mapping tool. The results show signal bleeding into the public lobby and a coverage dead zone in the records room. The team lowers AP transmit power near exterior walls, adds a directional AP for the records area, and confirms no rogue SSIDs are present before going live.