Because of the flexibility and reporting capabilities built into most site survey applications, individuals can either knowingly, or accidentally, use these features to ‘Cheat’ and make survey data look different than it really is.
OK, I understand the word ‘Cheat’ is a pejorative, and connotes some sort of blatant attempt to break some rules or misrepresent. Many individuals just didn’t know any better when they applied these methods in their survey reporting. I’m not implying that these techniques suggest any malfeasance, only ignorance.
As a customer, the best protection against this type of deception is to request not only the paper or PDF report, but the actual data files so you can review and analyze the data directly.
Below are some of the techniques that allow one to modify and present survey data to reflect whatever you might desire.
Be wary of using any of these techniques on your own analysis or in reviewing data presented by other third parties.
Whether it’s on purpose, or merely an oversight, the use of any of these aforementioned methods may present site survey data in an inaccurate light.
Method 1 – Incorrect Signal Propagation Value
One of the easiest ways to save money and time in the data-gathering phase of an RF site survey is to minimize the number of actual data points collected.
Method 2 – Using ‘Auto Contrast’
One of the options in the Color Configuration is to set the ‘Auto Contrast Adjustment’ checkbox. Normally, the top of the color bar is always the same color, and the bottom is always its same color. Thus the middle is also always the same color. Thus a -65dBm is always represented by the same color on screen and in reports.
Method 3 – Use of ‘Banded’ Color Schemes
Another one of the many Color options typically available is ‘banded colors’. The use of this color option is sometimes applied to show what is ‘acceptable’ or not. Above a certain color band is approved, and below is unacceptable.
Method 4 – Access Points Where No Data Exists
It is easy and possible for accidents to take place and an access point is placed not where it is in real life, but where you’d like it to be. Or the opposite, one can place an access point where it is in the real world, but not have any data collection points near that location.
Method 5 – One-Sided Guesses
No ‘One Way Guesses’. This happens when you don’t capture on both sides of what you care about. If you take one data capture point on the inside perimeter of your building, and don’t also take one on the outside, then the site survey application doesn’t know anything about the ‘thickness’ (in RF Attenuation) of the exterior wall. It ‘learns’ this by having data captures on both sides of the wall.
Method 6 – Not Enough Data Points
If the SPA is set to 5m, then there needs to be a red dot or a blue dot every 5m. Simple. More dots is fine, but fewer dots than your SPA will result in white spaces showing up on the floor plan. Then you might be tempted to increase the SPA in order to ‘hide’ these white spots.
Method 7 – Uncalibrated Survey
When you start a new site survey project, you are given the option to enter the drawing’s dimensions (not the building’s dimensions, but the drawing’s dimensions). If you leave it blank, (normal) some survey applications, such as AirMagnet Survey, will calibrate your drawing to a square 150’ x 150’. This will be your telltale sign you have NOT calibrated yet.
Method 8 – PDF or JPEG Only
As a customer, you should request the PDF report, possibly the survey graphics in JPG format, but most importantly the actual survey files. This way you can do your own analysis. Another means of misrepresentation is to not include the walking paths and data collection points. This, coupled with a high SPA, can be a sign the presented survey data is far too optimistic.
Method 9 – Showing Only the Results for a Single SSID
When analyzing survey data, it is very sometimes appropriate to include ONLY a specific SSID in the data set. In fact, this is the preferred method when analyzing for a (STA’s) device’s specific design requirements.
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