Wireless problems we solve
Passive, Active, Predictive or AP-on-a-Stick: Choosing a Wireless Survey
Survey type follows the question you need answered — what the RF is, what a client experiences, what a design predicts, or whether a placement works.
Engineer’s questionDo I need a passive survey, active survey, AP-on-a-Stick survey or validation survey?
1 — Direct answer
The short answer
Choose the survey by the question, not by the budget. A predictive design answers 'where should APs go?' before anything is installed. An AP-on-a-Stick survey answers 'will this placement actually work in this construction?'. A passive survey answers 'what is the RF environment right now?'. An active survey answers 'what does a connected client actually experience while moving?'. A validation survey answers 'does the installed network meet our documented criteria?'.
Most real engagements combine them. A new build typically runs predictive design, AP-on-a-Stick verification in unusual construction, then a validation survey at handover. A performance complaint typically starts with a passive survey plus spectrum analysis, and adds active measurement where mobility is involved.
The wrong survey produces a report that does not answer the question — the most common example being a passive-only survey commissioned to diagnose a roaming or throughput complaint.
Likely causes, roughly in order of frequency
- Predictive design
- Modelled RF design from floor plans and material assumptions. Used before installation to determine AP count, placement, antenna and channel strategy.
- AP-on-a-Stick survey
- Physical testing of candidate AP locations with real hardware in the real building, used to confirm assumptions in difficult or unusual construction.
- Passive survey
- Measurement of the RF environment without associating: RSSI, SNR, noise floor, channel usage and AP overlap. Best for coverage and interference questions.
- Active survey
- Measurement as a connected client: throughput, loss, latency, roaming behaviour and data rates along real routes. Best for mobility and performance questions.
- Validation survey
- Measurement against documented acceptance criteria after deployment or remediation, producing pass/fail evidence.
2 — Symptoms
Symptoms and what they usually mean
| Symptom | What it usually indicates |
|---|---|
| You are designing a new building or refresh | Predictive design, with AP-on-a-Stick where construction is hard to model. |
| Users report dead zones | Passive survey against a written coverage requirement. |
| Mobile devices drop while moving | Active survey along the real routes, usually with packet capture. |
| Throughput is poor with good signal | Passive survey plus spectrum analysis and airtime measurement. |
| A project is completing and needs sign-off | Validation survey against documented criteria. |
| You suspect interference | Spectrum analysis, usually alongside a passive survey. |
3 — Do this first
Safe checks you can run yourself
These are non-disruptive checks a competent network engineer can complete with the controller or cloud dashboard already in place. Do them before changing configuration — they frequently identify the cause, and they always make an external investigation faster and cheaper.
- 1
Write down the question you need answered
If you cannot state it in one sentence, no survey type will produce a satisfying report.
- 2
Define the applications and their requirements
Scanning, voice, medical telemetry and general data imply different targets and therefore different measurement.
- 3
Establish whether devices are stationary or mobile
Mobility almost always requires active measurement, not passive alone.
- 4
Gather floor plans and an as-built AP inventory
These materially affect scope, cost and accuracy of any survey.
- 5
Identify constraints on site access
After-hours, cleanroom, clinical or secure-area restrictions shape how a survey can be performed.
4 — Watch out
Common mistakes and misleading indicators
“A predictive design is enough on its own”
It is a model. In unusual construction, and always at handover, measurement is what converts it to evidence.
“A passive survey diagnoses everything”
It cannot measure throughput, roaming behaviour or application experience, and it cannot see non-Wi-Fi interference.
“An app-based survey on a phone is equivalent”
Phone radios and APIs report limited, vendor-specific data; they are useful for a quick look, not for design or acceptance.
“One survey covers a multi-site estate”
Sample sites can inform a reference design, but each site's construction and layout produces different RF.
5 — Escalation point
When normal troubleshooting is no longer enough
- The result will justify significant spend or contractual acceptance.
- The environment is clinical, industrial, high-density or otherwise hard to model.
- You need an independent second opinion on someone else's design or survey.
- Multiple device types with different requirements must all be satisfied.
- Internal tooling or time is not available to survey to the standard the decision requires.
6 — Professional investigation
What a professional wireless investigation should measure
- Requirement definition
- Applications, client types, coverage and capacity targets documented before survey design.
- Survey design
- The right combination of predictive, AP-on-a-Stick, passive, active and spectrum work for the question asked.
- Professional measurement
- Enterprise survey platforms and spectrum hardware, with calibrated floor plans and documented methodology.
- Analysis
- Coverage, SNR, overlap, data rates, roaming, airtime and interference interpreted against the stated requirement.
- Reporting
- Findings, heatmaps, recommendations and, where applicable, pass/fail against criteria.
7 — Relevant service
Which NetRobin service applies
Wireless Site Surveys
The survey programme should be designed around the question you need answered. Passive, active and AP-on-a-Stick surveys each have a dedicated methodology page, and most engagements combine more than one.
8 — Deliverables
What you should expect to receive
- A survey scope matched to the question and the applications involved
- Measured heatmaps and data appropriate to the survey type
- Findings interpreted against documented requirements
- Design, remediation or acceptance recommendations
- Methodology documentation suitable for internal or third-party review
Direct answers
Frequently asked questions
- Do I need a passive survey, active survey, AP-on-a-Stick survey or validation survey?
- Passive for coverage and RF-environment questions, active for mobility and client-experience questions, AP-on-a-Stick to prove placements in difficult construction before cabling, predictive to design before anything is installed, and validation to prove a deployed network meets documented criteria. Many projects use several.
- What is the difference between a predictive design and a site survey?
- A predictive design is modelled from floor plans and material assumptions; a site survey measures the real environment. Prediction plans the deployment, measurement proves it.
- What information is needed to quote a wireless survey?
- Floor plans with dimensions or scale, the areas and square footage in scope, building type and construction, ceiling heights, the applications and device types that must be supported, existing AP inventory and platform if any, site access constraints, and the decision the survey needs to support.
- When should I hire a wireless consultant instead of continuing internal troubleshooting?
- When the problem needs measurement your team cannot take — spectrum analysis, over-the-air packet capture, calibrated survey data — when changes have produced inconsistent results, when business-critical applications are affected, or when a decision needs independent evidence rather than another configuration change.
10 — Next step
Request a Site Survey
Tell us the question you need answered and we will recommend the survey type — including when you do not need one.