A WiFi site survey is a set of measurements and observations that shows how wireless signals behave in a specific building and whether the network can support the people and devices that depend on it. It is the basis for designing a new network, fixing a poor one, or proving that an installation does what it was meant to do.
Radio signals do not respect floor plans. Concrete, brick, metal studs, elevator shafts, mirrored glass, stocked shelving and even people absorb or reflect WiFi signals in ways that are hard to predict from a drawing. Two buildings with identical layouts can behave very differently because of what the walls are made of or what sits on the racks.
A survey replaces assumptions with evidence. Instead of adding access points wherever people complain, you find out whether the problem is weak signal, interference, too many users on one access point, a poor channel plan or a configuration fault. Each of those has a different fix.
What a survey measures
A survey collects readings as a surveyor walks the space with a laptop or handheld running survey software. At ehZee we use AirMagnet Survey Pro. Typical measurements include:
- Signal strength from each access point, usually expressed in dBm. See RSSI, SNR and signal strength for what the numbers mean.
- Signal-to-noise ratio (SNR), the gap between the WiFi signal and the background noise. A strong signal in a noisy environment can still perform badly.
- Channel use and overlap, showing where several access points on the same channel compete with each other.
- Neighbouring networks from tenants and adjacent buildings that share the same airspace.
- Data rates, throughput and connection quality, when the survey connects to the network as a client.
The software turns those readings into colour-coded heat maps laid over the floor plan, which make problem areas easy to see. WiFi heat maps explained covers how to read them.
Types of WiFi survey
Predictive survey
A predictive survey is a computer model built from floor plans and assumed wall materials. It is useful for budgeting and early design, especially before a building exists, but it is only as accurate as its assumptions. Predictive vs on-site WiFi surveys compares the two approaches.
Passive survey
The survey device listens to every access point it can hear without connecting. This shows coverage, signal strength, SNR, channel overlap and neighbouring networks.
Active survey
The survey device connects to the network and measures how a real client performs: data rates, throughput, packet loss and how it roams between access points.
Access point on a stick (AP-on-a-stick)
For new designs or major changes, a surveyor temporarily mounts an access point at a proposed location and measures how far its signal reaches through the actual building. This validates or corrects a predictive design.
Spectrum analysis
A spectrum analyzer looks for non-WiFi sources of interference, such as microwave ovens, wireless cameras or industrial equipment, that ordinary WiFi tools cannot identify.
What else a good survey covers
Radio readings are only part of the picture. A survey that leads to a working network also records the physical and business details that shape the design. Our checklist covers:
- Objectives: number of users, density, applications and bandwidth needs
- Installation: cabling, ceiling type, mounting options and IDF/MDF space
- Security: authentication through RADIUS and Active Directory, and physical security of equipment
- Extras: guest WiFi, RFID and asset tracking
- Radio environment: metal structures, neighbouring networks and SNR
When you need a survey
- Before designing a new network or replacing an old one.
- When users report dead spots, dropped calls, slow connections or devices that lose their connection in certain areas.
- When the building changes: new walls, racking, a change of tenant or a big increase in users.
- When adding voice over WiFi, location tracking or other services with stricter requirements.
- After an installation, to confirm that the network meets the design targets.
Start with requirements. A survey is only meaningful when it is measured against something. Agree on the coverage and signal targets for each area, based on the applications people use, before the survey starts.
What the report should give you
A useful survey report goes beyond pictures. It should state the targets used, show heat maps for each floor and band, explain what the maps mean in plain language, and list specific recommendations: which access points to add, move or adjust, and what to change in the configuration. It should also be clear about what was not covered, such as areas without access.
How ehZee can help
We carry out passive, active and validation surveys with AirMagnet Survey Pro, starting with a conversation about why you need the network and what it must support. Our WiFi surveys service gives you heat maps, plain-language findings and a ranked list of fixes, and can lead into design and build if you want us to carry the work through.
Common questions
How is a survey different from a speed test?
A speed test measures one device at one spot at one moment, mostly reflecting the internet connection. A survey measures the wireless network across the whole space and shows why performance changes from place to place.
Do we need to provide floor plans?
Yes, scaled floor plans make the heat maps accurate and easy to read. If you do not have current plans, let us know before the survey so we can plan around it.
Can a survey be done while people are working?
Yes. Surveying during normal use is often better, because it shows the network under real conditions and with real interference.