There are those that think site surveys are a waste of time, and that Predictive Surveys alone (they are not surveys by-the-way) are enough to get the job done. Sometimes, if the building is new construction, or a very open floorpan, etc. you'll get lucky and things work out. But, as the Tweet above shows, just because a wall looks like it’s regular old drywall, doesn’t mean it is. Site surveys save a lot of heartache by taking as much guess-work as possible out of the equation.
I'm not saying that a full "AP-On-A-Stick" type survey needs to be done throughout the entire facility, but I am saying that you should collect as much data as possible. We do “Predictive Models” here at CommunicaONE for most of our designs. However, we take as much guessing out as we can by performing a site survey at the location we’re designing for.
Things you really want to know: attenuation/loss through walls, glass, tile (is this REALLY just drywall, or is or merely a facade over BRICK?) ; is there RF interference that may cause issues, are there fixtures, appliances, building materials that cause unexpected RF attenuation, reflections, refraction (oh, the 200 gallon fish tank wasn't in the floor plans?), scattering, etc. These are things that can only be known by a site survey.
The moral here is when designing a WLAN you should get as much information as possible to about the environment you are designing for. Knowing what your building materials are, and what their RF characteristics are, will help go a long way in making WLAN designs as accurate, and successful as possible.
Not everyone has the time, nor can afford the tools needed to properly perform a survey. CommunicaONE can help by performing site surveys, spectrum analysis, and valuable data collection about your existing infrastructure, device types and capabilities, applications, and more, to help make sure that we have as much information as possible to design the best WLAN for your organization.
Hey, it’s a corporate blog, did you not expect a sales pitch? 😏
For a good overview of how to properly determine and document wall attenuation see Devin Akin's blogpost here.