One of the cool things about this business is construction. I love the smell of new construction and renovation; and it's just invigorating to make things new and old things improved. We've been busy doing site surveys and hashing out what's wrong with campus Wi-Fi networks that we've been reviewing: The technology picks are wrong, the methods of deployment are haphazard, and not understanding best I&M (Installation and Maintenance) practices are the common ailments.
Some assume that hanging the APs above the ceiling grid is the best place or method to conceal them. In our situation we decided against that, knowing the building and some working history. Other installers don't always have that luxury. So the tip is simple: before you hang APs above the ceiling grid, inspect the ceiling tiles. Do you see water stains? Are all floor penetrations fire-stopped and waterproofed?
We installed all the APs on walls below the ceiling tiles, and while this is more work concealing the cable, it doesn't mean degraded signal penetration. The transmitters emit "radio waves" and for you newbies, take note that radio waves bounce. In the old days, we'd use terms like "skip land" referring to bouncing our CB calls out across the ionosphere to see if radio operators could pick up our transmissions in other states. APs transmit bounce signals too, but how they bounce, where and how much signal strength varies from building to building. The factors include building materials, windows, and walls, and whether the wall cavities are filled (Doctors' offices are usually filled with dense sound bat) and then thickness of walls, door materials with penetrations and/or windows and ceiling heights are all factors in how the signal will bounce, as well as saturation.
So mounting APs on walls can present challenges too, but first make sure that wall isn't supporting cabinetry or plumbing (abandoned or existing), and don't mount APs into door swings--meaning when a door is opened or closed, will it use the AP as a doorstop?
Our site plan wasn't overly generous, to ensure that we provided adequate saturation for the practice. Because of the length of the building and its ends curving outward, we installed from one end first. We found where the signal dropped and then added our next AP and then re-measuring signal strength, we repeated the process. At the other end of the building that has a T-shaped end, we did not install an AP at the apex point of the T. Otherwise, because of the signal strength we achieved; we'd oversaturate the building. What I am suggesting is go light because we ended up pulling out one AP to avoid oversaturation. Generally speaking, you may get 1,500-2,500 square feet with just one AP, but that's in an open space, fabric cubicles and high ceilings, and still you may get less because it depends upon those variables. This particular building is about 6,500 square feet per floor and we used four 802.11n APs on just one floor.
For those folks that insist on installing long cable drops (I consider long as anything >150 feet) then I suggest you consider using Cat6 and use plenum regardless of the fire code requirement; meaning Teflon rated cable (CMP) stands up better to heat in ceilings; heat affects resistance thus packets.
Installing APs--if you use EZ anchors don't use the pan head (rounded top) screws that come with the EZ anchors. Replace the pan heads with drywall screws (flathead) of the same length; otherwise some of the mounting brackets will not seat into the AP because the pan head screw head is rounded and protrudes past the clips.
When installing the mounting brackets on drywall surfaces: use your mounting bracket's center and largest hole as a template. Before you chisel a hole for your cable, make sure your AP doesn't pop the ceiling tile when and if you need to remove the AP from the mounting bracket. Since most installers don't carry hammers and cordless routers, just take your dykes and a flathead screw driver and bang away using the hole in the bracket as your guide. Now for those not doing this every day, tap-tap-tap the drywall location before you notch out a hole for your cable and make sure you're not trying to notch into the vertical metal stud or any blocking you don't know about. Pop your head above the grid and look at the header. Most of this isn't revealed on a site survey plan, but you can look for telltale signs of blocking and plumbing.
Take a 6-8-inch piece of leftover ceiling tie or a piece of coat hanger, and bend a loop on it to form a hook. Use this to grab the cable inside the wall. Otherwise you will spend too much time mounting APs and fishing wire through a small hole. The mounting brackets on most APs leave little tolerance when mounted on drywall, and since most drywall isn't perfectly flat (you just can't see it) your tolerance level or patience drops over time because it will be tested.
Then, because it drives me a little crazy seeing dirty gear on installations--because drywall dust, dirt and grime and anything nasty in the ceiling grid or inside the walls is hard to avoid; just use a damp paper towel with water or spray some Windex on the paper towel and clean that AP.
For those that run drops (cabling) for APs, make sure you leave a service loop of 3-6 feet. This allows you to move the location of the AP and even before you mount the AP to the wall, grid or other location, you want to test your signal strength first. Those few extra feet can make a big difference of not having to return to the jobsite and run new cables because the AP location just didn't work out. The other reason is, what you can't see inside the walls can prevent you from concealing cabling because of unseen obstructions. Having that few extra feet in length can make a difference in where you can drop the cable into the wall successfully.
Next time, I'll cover those other ailments that we see not just on campus networks but in plenty of businesses that run amuck because someone can order Wi-Fi and throw it in without much thought.
