A site survey is a study of a building or campus, done on site or with modeling software, to plan or verify how technology will be installed and how it will perform. In networking, the term most often refers to a wireless site survey that maps Wi-Fi coverage and decides where access points should go. It is also used for cellular coverage surveys, which judge whether a building needs signal improvement, and for physical surveys of cable paths, wiring closets, power and the point where carrier services enter the building. The common thread is that each replaces assumptions with measurements and drawings before money is committed.
At a glance
- Wireless surveys can be predictive (modeled from floor plans), passive or active (measured on site), or post-installation validation.
- Cellular surveys measure mobile carrier signals indoors to decide whether a booster or distributed antenna system is needed.
- Physical surveys check cable routes, closet space, power, cooling and building entry before installation.
- A good survey produces drawings and measurements that later bids and installs can be held to.
- Skipping a survey is a common reason for Wi-Fi dead spots, change orders and delayed installs.
What problem it solves
Buildings vary widely in how they affect signals and installations. Concrete, metal, glass, elevator shafts, shelving and even people absorb or reflect radio signals. Ceilings may be inaccessible, closets may be full and conduit may not exist where a drawing shows it. Designing a network from a floor plan alone can leave dead spots, too many or too few access points, or cabling that cannot be installed as planned.
A survey reduces that risk. It gives designers real data about coverage, interference and physical conditions, and it gives buyers a baseline to compare vendor proposals and to check that the finished installation meets the agreed design.
How it works
Predictive Wi-Fi design. A designer loads floor plans into modeling software, assigns wall and material types, and sets targets for coverage, capacity and roaming. The software suggests wireless access point locations and channel plans. Its accuracy depends on how well the model reflects the real building.
On-site wireless survey. A technician walks the space with measurement tools. A passive survey listens to existing networks and interference; an active survey connects to the network and measures throughput, latency and roaming. An “AP-on-a-stick” survey temporarily mounts an access point to test candidate locations in difficult spaces.
Validation survey. After installation, a measurement pass checks that the wireless LAN meets the design targets. This is the evidence to hold an installer to.
Cellular survey. Engineers measure signal from each mobile carrier across the building to decide whether a cellular signal booster or a distributed antenna system (DAS) is needed and where antennas should go.
Physical survey. Technicians check pathways, ceiling access, wiring closets, power and cooling, and the route from the carrier entry point to the equipment room. Findings feed the structured cabling design and carrier orders.
For planning building networks end to end, see our wired and wireless LAN infrastructure page.
When it matters for buyers
- New offices and fit-outs. Surveying before walls and ceilings close lets cabling and access point positions be built in.
- Persistent Wi-Fi complaints. A survey can show whether the problem is coverage, capacity, interference or client devices.
- Changes in use. New shelving, more users, new devices or a move to voice over Wi-Fi can make an old design inadequate.
- Poor indoor cell signal. Measure before buying a booster or DAS so the solution matches the actual problem.
- Comparing bids. If every bidder designs from the same survey, proposals are easier to compare.
Questions to ask vendors
- What type of survey will you perform: predictive, passive, active, validation, cellular or physical?
- What coverage, capacity and roaming targets will the design be built to?
- Which tools will you use, and what will the report include?
- Will you account for the devices we actually use, such as phones, scanners or laptops?
- Is a post-installation validation survey included, and what happens if targets are not met?
- Who owns the survey files, and can we share them with other bidders?
How it differs from a network assessment
A network assessment reviews an existing network’s design, devices, performance and risks, largely from configurations, monitoring data and interviews. A site survey focuses on the physical space: how signals behave in a building and where equipment and cabling can go. An assessment may recommend a site survey when it finds wireless or physical issues, and the two are often combined in larger refresh projects.