Wireless Surveys

What this chapter covers

This chapter covers the work of measuring and modelling a place before and after you build a wireless network.

A design made only on paper often fails once real walls, people and neighbouring networks affect the signal. Surveys and analysis give you evidence, so that you can place access points and choose channels with confidence.

The chapter has two topics. One covers site surveys and their types. The other covers spectrum analysis and prediction software, which are the two tools that support a survey.

How the topics fit together

The tools work best in a sequence.

Prediction software gives a first layout from a floor plan. A spectrum analyser shows what is already in the air, including devices that are not Wi-Fi. The site survey measures the real signal in the real building, and a validation survey after installation proves that the design works.

• Site surveys explains the predictive, passive and active types, what to measure and what to record.
• Spectrum analysis and prediction software explains analyser views, common interference sources, heat maps and the limits of a model.

How to use these pages

Each topic page has the same shape, so you can skim for what you need.

• What it is: the idea in plain words.
• How it works: the mechanism, with diagrams and example commands.
• What to remember for the exam: the facts to memorise.
• Common mistakes: the classic traps.
• Check yourself: three questions to test your understanding.

Read the site survey page first, because it sets out the full process. Then read the analysis page to see how the other tools fit into that process.

If you can, run a scan or a spectral scan on a MikroTik radio and compare the results with the text. Write down which tool you would use for each kind of question, and check your list against the pages.